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Avian Pathology Seminar Monday 11 & Tuesday 12 June 2012

Monday 11 June 2012 09.25 Welcome and opening remarks 09.30 Introduction and scope of the seminar. CAHFS labs and its mission. Principles of disease diagnoses 10.00 An overview of Avian Anatomy 10.45 Refreshments 11.05 Anatomy (continued) and Avian inflammation 11.50 Poultry Pathology based on aetiologies 12.30 Lunch 13.30 Poultry Pathology 15.00 Refreshments 15.20 Poultry Pathology 16.30 Q&A 16.45 Finish

Tuesday 12 June 2012 09.25 Welcome to Day 2 09.30 Pathology of Pet and Exotic birds based on etiologies; PDD/Avian Bornavirus and Chlamydiosis 10.45 Refreshments 11.05 Pet and Exotic Bird Pathology 13.00 Lunch 14.00 Pet and Exotic Bird Pathology 15.15 Refreshments 15.35 Interesting and Challenging Cases of Pet/Exotic and Wild Birds 16.30 Q&A 16.45 Finish

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Participants List

Baird Pauline Margaret (AFBI Omagh) Beard Philippa Mary (University of Edinburgh, Midlothian) Blundell Richard (School of Veterinary Science, Liverpool) Cooper John Eric (School of Veterinary Medicine, University of Cambridge) Cserep Tibor (Cambridge) Debyser Isolde (Belgium) Deuchande Rita (AHVLA Sutton Bonnington, Leicestershire) Done Stanley Herbert (North Yorkshire) Erles Kerstin (The Royal Veterinary College, Hatfield) Errington Helen (AHVLA Penrith, Cumbria) Fernandez -Gutierrez Africa (Newbridge) Garcia-Rueda Cristina (AHVLA-Lasswade Midlothian) Gaudie Catriona (AHVLA Thirsk, North Yorkshire) Hargreaves Judith (Abbey Veterinary Newton Abbot) Harrison Robert (Sci-Tech Laboratories Ltd) Irvine Richard (Animal Health & Veterinary Laboratories) Jahns Hanne (School of Veterinary Medicine, Dublin) Jeckel Sonja (RVC-AHVLA Surveillance Centre, North Mymms) Knott Chris (Finn Pathologists, Norfolk) Mackinrosh Adrienne (AHVLA Carmarthen) Otter Arthur (AHVLA Shrewsbury) Patterson Ivan Antony Paul (Down) Pocknell Annabella Marie (Finn Pathologists, Norfolk) Regenhard Petra (Lohmann Animal Health, Cuxhaven) Salvatori Daniela (Netherlands) Shivaprasad H (University of California) Smith Sionagh (Veterinary Pathology Unit, Midlothian) Spencer Stephen (MSD Animal Health, Milton Keynes) Thorp Barry (Carlops, MID) Van der Heyden Sara (Brussels) Vrijenhoek Mieke (MSD Animal Health, Boxmeer) Welchman David (AHVLA Winchester, Winchester) Wessels Julie (AHVLA Preston) Wight Alan (AHVLA Winchester) Wilson Margaret Mary (Pathology, Belfast) Wood Alisdair (AHVLA Lasswade)

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Biography H. L. Shivaprasad Is a Professor of Avian Pathology with the California Animal Health and Food Safety Laboratory System (CAHFS), University of California, Davis since 1989. He obtained his BVSc from India, PhD from The Ohio State University, USA in 1977 and residency training in Veterinary Pathology from Purdue University, USA 1978-1980. He was a faculty member in Veterinary Pathology at University of Illinois (5 years) and in Avian Pathology at Cornell University (4 years) before joining CAHFS. He is board certified by the American College of Poultry Veterinarians. He has been involved in avian diagnostics, teaching and research for more than 32 years. His primary research interests are to identify novel etiologies and diseases of both infectious and noninfectious nature and study their pathogenesis in avian species. He has published extensively in journals, books and proceedings and has presented numerous papers in national and international conferences. He is a member of many professional organizations, serves on the editorial board of two journals and is an ad-hoc reviewer of a number of other journals. He has traveled to more than 35 countries on invitation primarily for teaching.

H. L. Shivaprasad California Animal Health and Food Safety Laboratory System, Tulare Branch School of Veterinary Medicine, University of California, Davis 18830 Road 112. Tulare, CA 93274 Tele: 559-688-7543, Fax: 559-686-4231 E-mail: hlshivaprasad@ucdavis.edu

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CAHFS Mission, Laboratories,

Services Offered and Principles

of Disease Diagnoses

H. L. Shivaprasad

California Animal Health and Food Safety

Laboratory System, Tulare Branch

University of California, Davis

School of Veterinary Medicine

University of California, Davis

To provide the citizens of California with the highest quality diagnostic laboratory support for:

California Animal Health & Food Safety

Laboratory System

Mission

CAHFS Mission

Public Health

New Knowledge

Health

Management

Equine Health

Food SafetyDisease Control

California Animal

Health

& Food Safety

Laboratory System

Davis

Turlock - Avian

Tulare

San Bernardino

Broilers

Turkeys

Layers

2001 CAHFS

Services offered at each laboratory

Davis Turlock TulareSan

Bernardino

Bacteriology

Immunology

Biotechnology

Path/Histo

EM

Toxicology

Avian Virology

Mamml. Virology

Each of four laboratories offer services to match the needs of the animal

populations located within the immediate vicinity of that laboratory

California Animal Health & Food Safety

Laboratory System - Organization

Dean

School of Veterinary Medicine

Secretary

California Department of

Food and Agriculture

Veterinary Diagnostic

Laboratory Board

Director

Administrative

Council

John E. Thurman, Jr.

Veterinary Diagnostic Lab

Turlock TulareSan

Bernardino

Kenneth L. Maddy

Equine Analytical Chemistry Lab

Davis

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Avian Taxonomy

Phylum: Chordata

Class: Aves

Orders: 27

Families: 160

Genera: 1800

Species: 8600

Subspecies: >22,000

Major Categories of Birds

Domestic poultry (Egg laying and broiler

chickens, turkeys and ducks)

Game birds (Pheasant, Quail, Chukar)

Pet and exotic birds

Ratites (ostrich, emu, rhea)

Birds of Prey

Free flying birds

Birds in captivity (Zoos)

Segments of Poultry Industry (Broilers, turkeys, egg layers)

Breeding – genetics

– breeder replacements

Hatchery/custom hatching

Nutrition (feed/feed mills)

Housing – brooding/grow out (meat type)

Vaccines and vaccination

Egg production , processing (meat/eggs)

Transportation

Poultry Industry US/California

Eggs (Pullets/layers) – WLH, BLH, NH

Broilers/Fryers & Roasters (meat-type )

White Plymouth Rock, White Cornish

Turkeys (Large White - Toms/Hens)

Ducks (Pekin/Muscovy/Mullard)

Pheasants (Ring necks: 18 - 20 weeks)

Squabs (500 g - 4 weeks)

Quail (meat/eggs), others?

Components of a Poultry House

Litter

Temperature (brooders, heaters, foggers)

– ventilation - fans, windows, curtains

Lighting (programs)

Water/drinkers

Feed/feeders

Mortality, pick up of dead birds

Manure disposal, fly and rodent control

Cages, pens, nest boxes, AI (turkeys)

Records, records, records, re….

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Poultry production in US/Cal

2006-2007

Industry United States CaliforniaCal. Rank

#

Broiler** 49.2 bill. Lbs. 4.4 bill. Lbs. 10

Turkey 262 mil. 15.8 mil. 6

Egg 344 mil. 18.4 mil. 4

Per Capita Consumption (lbs.) of

Meat in US

Year Chicken Turkey Beef Pork Fish Lamb

1975 25.2 6.7 83.2 38.5 12.1 1.3

1985 35.2 9.2 74.7 48.1 15.1 1.1

1995 48.5 14.1 64.0 49.1 14.9 0.9

2000 57.7 14.1 62.4 48.3 14.5 0.8

2006 87.0 16.9 65.8 49.4 16.5 0.8

Per Capita Consumption (lbs.)

of Eggs in US

Year # Eggs

1945 402.0

1991 233.5

1996 238.0

1999 255.0

2000 252.0

2006 255.0

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California Animal

Health

& Food Safety

Laboratory System

Davis

Turlock - Avian

Tulare

San Bernardino

Broilers

Turkeys

Layers

Poultry Industry in

US/CaliforniaEggs

Broilers/Friers (meat chickens)

Turkeys

Ducks

Pheasants

Squabs

Quail, others?

Pet Bird Industry in US

Value not known, one to three billion dollars?

–Includes sale of birds, supplies, feed, veterinary

care, etc.

45 – 55 (20 – 80) million birds in US?

–15 to 17 million households

One million birds purchased each year?

Wildlife conservation act of 1992

Smuggling of birds?

California – has many outdoor aviaries

Florida, Texas, Georgia, Arizona

Why use a Laboratory ?

To find out why bird/s sick or dead

To control diseases or outbreaks

To diagnose zoonotic disease

To diagnose/monitor Foreign Animal

Diseases (ex; Bird Flu, END, etc.)

To gain knowledge on new disease/s

Surveillance/trends/conservation

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Causes of Disease

M: Malformation, Metabolic

I : Infectious, Immunologic

N: Neoplasia, Nutritional

T: Toxic, Trauma

Note: in commercial poultry infectious, nutritional and toxic causes are most important

Infectious

Bacteria

Viruses

Fungi

Parasites

Rickettsia

Tests Essential for Disease

Diagnosis

History

Clinical signs

Necropsy (autopsy)

Serology (ELISA, HA/HI, AGID, etc.)

Immunology (FA, etc.)

Bacteriology/Mycology

Biotechnology

Tests Essential for Disease

Diagnosis Histopathology

Immunohistochemistry

Parasitology

Toxicology/Nutritional analysis

Electron microscopy (DEM/TEM/SEM)

Virology (egg embryos, cell culture)

Hematology, chemistry, cytology

Pathogenicity tests

Biotechnology

PCR (RT-PCR)

–AI , NDV, vv/IBDV, IBV, WNV, ILT, Reo, Rota,

Astro, Herpes, Adeno, Polyoma, PBFDV

–Bacteria (MG, MS, S. Enteritidis,

Avibacterium), protozoa, fungi

RAPD – MG (fingerprinting), RFLP - ILT

5.8S, 16S and 23S rRNA gene for bacteria

Sequencing - IBV

Microarrays (Virochip) – Bornavirus (PDD)

Standardization and validation?

Approach to Disease

Diagnosis

Obtain proper and complete history

Develop differential diagnoses

Do complete necropsy

Follow protocols for submitting samples (AAVLD/OIE - ISO - QA/QC)

Send preliminary report

Collate all test results

Develop a final report

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Specimens Necessary for

Diagnosis

Diagnosis is as good as the specimens submitted

Sampling (representative) of birds –most important especially in poultry

Bird(s), live or dead

Tissues (fresh, frozen, fixed)

Swabs, blood, feces

Feed, water, egg/s, soil, etc.

Diagnostic Protocol

Turn around time: Reporting

Significant (and routine) findings reported same day

Serology, bacteriology, biotechnology, Direct EM, histopathology – 24 to 72 hours

Toxicology - 3 to 5 days

Mycoplasma - 2 weeks

Virology - 3 to 6 weeks

Others - variable

Disease Diagnoses – Philosophy

Quality: Accuracy of results

Rapid turn around time

Thorough diagnostic work up

Communication with the clients

•Use of friendly, common and

understandable language

Disease Diagnoses – Philosophy

Quality of service depends on the

‘quality and quantity of effort’ by

the diagnostician

sometimes it is difficult to find the

cause

Client Confidentiality important

Submission of specimens to

CAHFS

Submission form – available @ CAHFS website, http.//cahfs.ucdavis.edu

Provide detailed history such as age, species, symptoms, how long, number of birds involved, mortality, treatment, etc.

Provide name, address, telephone #, FAX #, E-mail, cell phone #, etc.

Information on type of tests done, cost, specimens to be submitted, laboratory to use, etc., refer to the CAHFS website

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Pathology of Birds – An Overview Introduction Similar to other animals, birds are susceptible to a variety of diseases. Knowledge about the type of birds, their anatomy and how they are managed helps to understand the type and kind of diseases different birds are susceptible to. Because some types of birds are raised for egg production or meat, such as commercial poultry, infectious diseases can spread rapidly among birds raised in a confined space. Poultry can also be raised in small numbers as backyard flocks. Often poultry raised in such conditions are more often exposed to natural elements and are often not vaccinated; poor nutrition and lax biosecurity can lead to frequent viral, bacterial, parasitic and nutritional diseases. Pet and exotic birds such as psittacines and passerines are raised in small or large aviaries, sold in pet shops and kept as pets. These birds have their own unique diseases that can be influenced by management. There are also free flying birds that face ever shrinking habitats and ecosystems as well as undergoing changes. Therefore, diseases in such birds are greatly influenced by environmental factors. Numerous birds raised or kept in captivity as in zoos have a different and unique environment. Regardless of whatever management practices are used, genetics and nutrition play a significant role in the initiation and outcome of a disease.

This handout on the pathology of birds is an outline and is by no means complete. There are a large number of miscellaneous diseases or pathological conditions that have not been included in this outline. Those who are interested in learning more are advised to review the references provided at the end of this outline. Taxonomy There are over 22,000 subspecies and 9300 species of birds classified in 166 families, 27 orders in the class Aves. Order Passeriformes contains the largest number with 5243 species of birds, and the Order Struthioniformes contains only one species (ostrich). The number of species in each order, along with representative species, is listed in the following table. The list starts with orders believed to be the most primitive and continuing to the most advanced.

Order

Species # Species

Struthioniformes ostrich 1 Rheiformes rheas 2 Casuariiformes emus, cassowary 4 Apterygiformes kiwis 3 Tinamiformes tinamous 40 Sphenisciformes penguins 17 Gaviiformes loons 4 Podicipediformes grebes 18 Procellariformes albatrosses, fulmars 86 Peliconiformes pelicans, cormorants, frigate, boobies 55 Ciconiiformes herons, egrets, storks, ibises, spoonbills, flamingos,

bitterns. 116

Anseriformes Ducks, geese, swans 145

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Falconiformes vultures, eagles, hawks, harriers, kites, osprey, falcons, buzzards

272

Galliformes chickens, turkeys, quail, pheasant, partridge, Guinea fowl, peafowl, grouse, chachalaca, guan, currasow, capercaille, ptarmigan, megapods

252

Gruiformes cranes, coots, rails, trumpeters, seriemas, bustards, bustard quails

199

Charadiformes gulls, murres, terns, avocets, puffins, woodcock, oystercatchers, sandpipers, plovers, surfbirds, snipes, skimmers

334

Columbiformes pigeons, doves and sand grouse 289 Pscittaciformes parakeets, Budgerigar, cockatiels, cockatoos, macaws,

parrots, lories, lorikeets, love birds 317

Cuciliformes turacos, cuckoos, roadrunners 147 Strigiformes owls 134 Apodiformes hummingbirds 398 Trogoniformes quetzal, trogons 34 Coliiformes mousebirds 6 Caprimulgiformes Oilbird, frogmouths, potoos, goatsuckers, nightjars Coraciformes toucans, barbets, woodpeckers, jacamars 379 Piciformes kingfishers, hornbills, hoopoes, rollers 199 Passeriformes Perching birds; finches, canaries, crows, ravens,

magpies, jays, American robins, mockingbirds, bulbuls, sparrows, starlings, mynahs, blackbirds, cardinals, chickadees, thrushes, tits, grosbeaks, buntings, tanagers, orioles, birds of paradise, larks, wrens, waxwings, waxbills, weavers, swallows, manakins, martins, antbirds, shrikes, etc., etc.

5243

Anatomy and Physiology Birds have a close evolutionary relationship with reptiles especially crocodiles. Their unique anatomy has helped the birds to adapt well to the environment. Even though there are numerous different species of birds, their anatomy shows a greater uniformity of structure than many single orders of fishes, amphibians, reptiles and mammals (King and McLelland, 1984). But there are anatomical differences between species of birds. A few salient features on the anatomy and physiology of birds are given below. Birds skin lack glands except for the uropygeal gland or preen gland present at the base of the tail and glands in the external ear. The uropygial gland is not found in all birds. Various appendages such as comb, wattles, ear lobes, snood, caruncles, beard, spurs, claws, scales are present in a variety of birds. Birds have pneumonic bones and air sacs extend in to the proximal humerus, vertebrae and pelvic girdle. Vertebrae are articulating and thoracic to sacral vertebrae are fused except for T-4 (previously T-6). Laying hens form medullary bone in response to estrogen, which serves as a source of calcium during laying. Trachea has complete rings and can overlap and syrinx is present. Syrinx is large in male waterfowl. Lungs are attached to the body wall. From trachea the primary bronchi passes through the lungs giving

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rise to many secondary bronchi before entering the abdominal air sacs. The secondary bronchi give rise to tertiary or parabronchioles and from there to atria and air capillaries where air exchange takes place. Lungs are of ‘paleopulmo’ (unidirectional movement of air) and ‘neopulmo’ (bi-directional) types. Cervical (paired), clavicular (single), anterior and posterior thoracic (paired) and abdominal (paired) air sacs are present. Birds have no diaphragm and they have eight coelomic cavities. Birds have four-chambered heart and the right atrioventricular valve is a muscular flap. Birds have beak, lack teeth, have mucus glands in the oral cavity and most birds have a food storage organ called crop. Salivary glands are present in tongue, etc. Proventriculus is the primary glandular stomach and the muscular stomach; gizzard is well developed in seed eating birds. It is lined by mucoproteinaceous material or koilin. Duodenum in the form of a loop encloses pancreas, a long jejunum and a small ileum comprises the small intestine. Ceca are paired and their presence varies among different species of birds. It is well developed in gallinaceous birds and ratites but appear as small knobs in columbiformes, passeriformes and absent in psittacines. Colon is longer than the entire small intestine in ostrich. Cloaca is compartmentalized and is the common opening for digestive, urinary and genital systems. Liver is composed of right and left lobes, which join cranially, and gall bladder is present. Some birds such as most pigeons, ostriches, and many parrots lack gall bladder and in some birds such as toucans, woodpeckers and barbets it is exceptionally long. Birds have no lymph nodes; thymus and bursa are the primary lymphoid organs. Thymus, seven pairs in chickens are located along the jugular vein. Bursa of Fabricius is pale and round in most birds elongated in ducks and is located dorsal to the cloaca. Bursa in chickens is present at hatch reaches maximum size between 6-12 weeks and undergoes involution between 18-22 weeks of age. Spleen is a secondary lymphoid organ and is round to oval in gallinaceous birds, ducks and psittacines but elongated in charadiiformes and passeriformes. Gland of Harder (Harderian gland) is another secondary lymphoid organ and is situated medially and dorsally on the posterior surface of the eye and it contains numerous plasma cells. Ceca have well developed lymphoid tissue, ‘cecal tonsils’ at the junction of ceca and colon. Cecal tonsils as well as Payer’s patches and gut associated lymphoid tissue occur as annular bands in waterfowl. Duodenum has well developed Payer’s patches. Paired lymph node-like structures present in duck and goose, one at the thoracic inlet near the thyroids and the second pair at the lumbar region. Lymphatics are present but not well developed. Kidneys are lobulated have no capsule and lack renal pelvis and have both mammalian and reptilian nephrons. Renal portal circulation present, venous blood from the legs, pelvic region and hindgut is carried to the kidneys. Avian excretory system is uricotelic; uric acid is the end product. Urinary bladder is absent. Most avian species have only left ovary and oviduct. Oviduct has five parts, infundibulum, magnum (albumen secreting), isthmus (shell membranes), uterus (shell formation) and vagina. Testes are paired and located at the cranial poles of the kidneys. Testes can enlarge greatly during breeding season. Seminal vesicle, prostate, bulbourethral glands are absent. Ratites, ducks, geese, swan have intromittent (protruding) phallus. Thyroids are oval fleshy organs located in association with the common carotid artery at the thoracic inlet. Parathyroids and ultimobronchial bodies (have C cells) are separate and are located posterior to the thyroids. Adrenals are located at the anterior poles of the kidneys. Adrenals lack a distinct cortex (pale staining cells with vacuoles in cytoplasm) and medulla (basophilic cells) but are ‘scrambled’. Pituitary is present in sella turcica posterior to the optic chiasm. There is no intermediate lobe in the

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pituitary. Most of the islets are located in the splenic lobe of the pancreas at least in chickens and turkeys. Brain lacks sulci and gyri but cerebellum has folia. Optic lobes are well developed, prominent and lie beside the corpora. Spinal cord has ‘glycogen body’ in the rhomboid sinus of lumbar segment. Eyes have pecten, scleral ossicles, single and multiple foveas. Extra orbital nasal or salt glands are present in the nasal septum, well developed in marine birds.

Ears lack external pinna and have a well-developed sound conducting structure in the middle ear called columella. External ears have glands.

Inflammation Reaction is rapid in birds, 36 hours Leakage of fibrin and fibrinogen common in early exudate Intense granulomatous reaction (12 hours)

– Coagulum of eosinophilic debris, degranulating heterophils, macrophages and giant cells Macrophages, heterophils and thrombocytes are active phagocytes Pus is caseous but liquefaction can occur Birds respond with granulomatous inflammation to many insults Acute inflammatory reaction in birds involve edema, congestion and vascular changes mediated by

basophils and mast cells – 1-3 hours: basophils, heterophils and monocytes – 2-6 hours: basophils degranulate and die – 6-12 hours: lymphocytes, monocytes, macrophages – 12-36 hours: lymphocytes, macrophages, giant cells

Acute reaction peak by 12 hours (when giant cells appear) – 36-72 hours: regeneration and repair

Fibroblasts, secondary lymphoid follicles, plasma cells Chronic reaction with caseation, macrophages, giant cells, granuloma formation

Cells involved in inflammation – Heterophils: have lance-shaped granules, lack myeloperoxidase and alkaline phosphatase, have

-glucuronidase and acid phosphatase Very phagocytic Granules tend to round up in tissues, difficult to identify

– Eosinophils: have spherical granules Function is not known, delayed type IV hypersensitivity? Associated with eosinophilic enteritis in turkeys due to ascarids

Basophils: contain histamine, involved in acute inflammation Thrombocytes: small round to oval cells with clear cytoplasm and small round nucleus (looks

like small lymphocyte), are phagocytic Monocytes: precursors to cells of Mononuclear Phagocytic System (MPS), phagocytic, can fuse

to form multinucleated giant cells. Make monokines; IL-1, IL-2, (IL-4?), IL-6, IL-8, (IL-10?), (IL-12?), IL-15, IL-16, IL-17, IL-18,

TNF, G-CSF, gamma interferon Lymphocytes: various morphologies involved in subacute inflammation including plasma cells

Coagulation Extrinsic system active and efficient but intrinsic system relatively weak Tissue thromboplastin (III) and platelets play important role

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Has a vitamin K dependent factor similar to mammalian factor IX – Plasma thromboplastin and Hageman factor may be lacking – Low levels or absence of factors V and VII

Fibrinogen (I), prothrombin (II), antihemophiliac factor (VIII) and Stuart factor (X) are present Clot retraction is very slow in birds

– Has thrombolytic mechanism and t-PA activation for fibrinolysis

Complement Not well understood Classical complement (CCP) and alternate complement pathways (ACP) are present A few components have been identified such as C1, C3, B

– may lack C2 and C4. Factor B in chickens may play a dual role in ACP and substituting for C2 in CCP Differences in C components may exist among avian species Bacterial Diseases Disease caused by E. coli, Salmonella, Chlamydophila, Clostridia, Mycobacteria, Mycoplasma, Pasteurella

multocida, Ornithobacterium rhinotracheale, Erysipelas, Bordetella, Avibacterium (previously Haemophilus and Pasteurella), Yersinia pseudotuberculosis, Riemerella anatipestifer, Staphylococcus, Streptococcus, Coxiella, Pseudomonas and other miscellaneous bacteria

Colibacillosis Disease of great economic significance in poultry Any one of the syndromes in poultry caused by E. coli

– Colisepticemia, air sac disease (CRD), peritonitis, coligranuloma, salpingitis, omphalitis/yolk sac infection, cellulitis, osteomyelitis/synovitis, swollen head syndrome and panophthalmitis

Enteritis with AEEC, eae gene present – Ceca most commonly involved – Common in turkeys, others; chickens, pigeons, quail, partridges, pheasants, ducks, ostriches,

psittacines, passerines, etc. Septicemia and enteritis in other birds? Salmonellosis Large group of acute, subacute or chronic diseases caused by one or more members of bacterial

genus Salmonella – Pullorum Disease in poultry, S. Pullorum – Fowl Typhoid in poultry, S. Gallinarum – Paratyphoid in poultry, ducks, pigeons, wild birds, psittacines, passerines, etc. – 10-20 species: S. Typhimurium, S. Enteritidis, S. Heidelberg, S. Anatum, S. Derby, S. Bredeney,

etc. Arizonosis in turkey poults, S. arizonae

– Also in chicks, ducklings, psittacines, passerines, etc. Lesions

– Pullorum/Typhoid In chicks: Septicemic lesions of omphalitis, hepatitis, peritonitis, necrotic typhlitis,

pericarditis, splenitis, pneumonia, synovitis, nephritis, ophthalmitis, etc. Pale yellow nodules in myocardium (histiocytes), intestine and gizzard in chronic cases

In adults: oophoritis, salpingitis, peritonitis, orchitis – Paratyphoid

S. Typhimurium most important

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In different species of birds: similar to acute septicemic lesions of pullorum and typhoid, In pigeons: brain, bone, and gonads often involved S. Enteritidis can cause septicemic lesions in chicks

Important in egg-associated food poisoning – Arizonosis, in turkey poults

Septicemic lesions, omphalitis, typhlitis, meningitis, Ophthalmitis, hepatitis, etc. Chlamydiosis Naturally occurring contagious systemic disease of various species of birds Chlamydophila psittaci, many serotypes (A, B, C, D, E, F, G*, E/B, others). C. abortus has also been

associated with disease in psittacines. G* in Red tail hawks – not published yet. Diagnosed in more than 400 avian species, 15 orders and 30 families Psittacines, 25% of the reported host species, others; pigeons, passerines, wild and feral birds,

rheas, turkeys, pheasants, etc. – Chickens relatively resistant

Clinical signs: vary greatly, species and age of bird, and strain of Chlamydia – Respiratory signs, oculonasal discharge, diarrhea often greenish colored, swelling above eye

(turkeys), conjunctivitis (pigeons), etc. Lesions: airsacculitis, pericarditis, pneumonia, hepatitis, splenitis, enteritis, conjunctivitis, nasal

adenitis (turkeys), synovitis, encephalitis, nephritis, etc. – Can also infect endothelial cells

Chlamydia pneumoniae has been associated with atherosclerosis in humans Chlamydia-taxonomy Order: Chlamydiales

Family: Chlamydiaceae Genus: Chlamydophila

Species: C. psittaci C. pneumoniae C. pecorum C. felis C. caviae C. abortus

Genus: Chlamydia Species: C. trachomatis C. suis C. muridarum

Chlamydophila psittaci – Obligate nonmotile, coccoid intracellular bacteria – Depends on host cells for ATP metabolites – Multiply within membrane-bound inclusions, in the cytoplasm of host cells – Have a non-synchronous multimorphic developmental cycle:

Spore-like, non-vegetative elementary body (EB), uniformly spherical particle of 300 nm diameter

Ingestion by host cell, fusion of bacterial endosome with host lysosomes? EB undergoes conversion to metabolically active reticulate body (RB), 800-1200 nm RB replicate by binary fission, within a membrane bound vacuole, the chlamydial inclusion Intermediate bodies (IB) can also be seen Mature to infectious EB’s which infect other cells by lysis of host cells or by extrusion of

chlamydial inclusion

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Clostridial diseases C. perfringens (type A most common) - necrotic enteritis in poultry, ratites, psittacines, etc. C. colinum - ulcerative enteritis in poultry, especially in quail (‘quail disease’), toucans, ratites,

chickens, psittacines, etc. C. colinum has also been associated with focal duodenal necrosis in chickens. – C. perfringens can also cause ulcerative enteritis in quail and turkeys

C. difficile - entero/typhlocolitis in ratites (ostrich) C. sordelli - enterocolitis in ratites (ostrich), omphalitis in baby chickens, ulcerative enteritis and

hepatitis in quail (similar to Quail Disease) C. chauvoei - enteritis in ostriches Liver may have foci of necrosis and inflammation with the above clostridial diseases C. septicum - gangrenous dermatitis in poultry, especially in turkeys, also in chickens (C. perfringens

can also cause similar lesions). C. botulinum - limberneck in poultry. One of the most important causes (others; lead and

Pasteurella multocida) of mortality in wild waterfowl. Clostridium piliformis (Tyzzer’s disease) - hepatic necrosis in psittacines C. tertium – associated with enteritis in Lorikeets Mycobacteriosis Chronic progressive disease of a variety of species of birds with unthriftiness, loss of weight,

diarrhea, etc. – M. avium - wide host spectrum, poultry, pigeons, raptors, ratites, wild birds, psittacines,

passerines, etc. – M. avium subspecies hominissuis associated with hepatic crirrhosis in a Blue Front Amazon. – M. genavense – most common mycobacteria of psittacines and probably passerines such as

canaries and finches. – M. tuberculosis - psittacines, others? – M. bovis – pigeons, psittacine, others? – M. peregrinum – granulomatous hepatitis in Gouldian finches and parrots – M. intermedium – granulomatous pneumonia in Oropendola – M. celatum - granulomatous pneumonia, hepatitis, splenitis, nephritis, osteomyelitis in white-

tailed Trogon – M. avium subspecies paratuberculosis associated with granulomatous hepatitis in a Diamant

sparrow – M. simiae complex associated with histiocytic hepatitis in Micronesian kingfishers

Lesions – Poultry, pigeons, raptors, ratites; grossly pale yellow or grey nodules in liver, spleen, intestine,

bone marrow, lung, heart, etc. micro: caseous necrosis surrounded by multinucleated giant cells and fibrosis

– Psittacines, passerines, turacos; grossly pale mottling or diffuse enlargement of liver, spleen, intestine, lung, heart, eyelid, skin, etc. micro: diffuse or focal infiltration of foamy macrophages with myriads of acid fast bacilli in

the cytoplasm. Lymphocytes and necrosis is not common. Mycoplasmosis Important economic diseases of poultry caused by

– M. gallisepticum

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– M. synoviae – M. meleagridis – M. iowae

14-20 or more Mycoplasma sp. are known – Isolated from chickens, turkeys, pigeons, raptors, ratites, wild birds, psittacines, passerines, etc. – Pathogenic significance? – M. imitans can cause conjunctivitis and sinusitis in red-legged partridges – M. sturni has been associated with conjunctivitis in a European starling, Blue Jays and

Mockingbirds M. gallisepticum (MG) – Disease called chronic respiratory disease (CRD) in chickens and infectious

sinusitis in turkeys. Other birds susceptible include, quail, pheasants, partridges, peafowl, finches, etc. – Egg transmitted – Respiratory disease with swollen infraorbital sinus, tracheitis, airsacculitis, conjunctivitis, etc. – Primarily lymphocytic inflammation – MG can cause decreased egg production in layers – Some strains of MG can cause neurological signs in turkeys due to vasculitis in the brain – MG has caused conjunctivitis in wild finches in the East, Midwest and Western regions of the US.

MG can cause amyloid arthropathy in Brown Leghorn chickens M. synoviae (MS) - in chickens, turkeys, geese, quail, partridge, ducks, etc.

– Egg transmitted – Subclinical infection of respiratory disease, sinusitis, tracheitis, air sacculitis, conjunctivitis – It can cause severe synovitis, ulceration – Lymphocytic inflammation, proliferation of synovial cells – Some strains of MS can cause neurological signs in turkeys, and chickens due to vasculitis in the

brain – Disseminated vasculitis in synovium, eye, kidney, skeletal muscle, heart, lung, etc., can be seen

in turkeys – Has also been associated with amyloid arthropathy in Brown Leghorn chickens

M. meleagridis - affects turkeys – Egg transmitted – Airsacculitis in day-old poults – Decreased hatchability, swelling of hock joint (chondrodystrophy), bowing of tarsometatarsus

(TS-65 syndrome), deformation of cervical vertebrae (wry neck) M. iowae - affects turkeys

– Egg transmitted – Causes decreased hatchability and embryo mortality – Chondrodystrophy has been described

Turkey Coryza (Bordetellosis) Caused by Bordetella avium

– Upper respiratory tract infection primarily of young turkey poults; swollen sinus, collapsed trachea, watery eyes Tracheitis: deciliation, squamous metaplasia, and lymphoplasmacytic inflammation

Decrease of GAGS (?) in the cartilage, effect of toxin? B. avium can be a significant pathogen in young broiler chickens, ratites, passerines and psittacines Infectious Coryza Disease primarily of young chickens caused by Avibacterium (previously Haemophilus)

paragallinarum

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– Pheasants and guinea fowl are also susceptible Upper respiratory tract infection; swollen sinus (sinusitis/rhinitis), facial edema, conjunctivitis Occasionally tracheitis, bronchitis and airsacculitis Fowl Cholera Also called avian cholera, pasteurellosis Septicemic disease of birds with high mortality and morbidity Etiology: P. multocida Most common in turkeys, chickens, wild waterfowl Other birds such as geese, quail, pheasants, raptors, psittacines, passerines, zoo birds, etc., are

susceptible Lesions

– Acute: petechiae on viscera, consolidated lungs (common in turkeys), enlarged liver with foci of necrosis, pericarditis, airsacculitis, cellulitis, endocarditis, etc. Mucoid enteritis in waterfowl Peritonitis and oophoritis in breeders

– Chronic: swollen wattles, synovitis, otitis, osteomyelitis of cranial bones, sinusitis, conjunctivitis, etc. Esophageal abscesses in raptors

Ornithobacterium rhinotracheale Gram negative bacillus associated with respiratory disease in poultry, primarily turkeys and broiler

chickens It has been isolated from layer-type chickens, pheasants, partridges, pigeons, psittacines, etc. Consolidated lungs (can be similar to fowl cholera in turkeys), tracheitis, airsacculitis, sinusitis,

peritonitis, hepatic necrosis, etc. Erysipelas Acute septicemic disease of primarily turkeys Etiology: Erysipelothrix rhusiopathiae Chickens, emus, pheasants, ducks, grebes, geese, chukars, raptors, psittacines, zoo birds, etc. Lesions

– Acute cases: hemorrhages over epicardium, abdominal fat, skin, muscle, congested and enlarged spleen, foci of hepatic necrosis

– Chronic cases: vegetative endocarditis and arthritis Pseudotuberculosis Chronic contagious disease of psittacines, canaries, finches, doves, poultry, raptors, wild birds, etc. Yersinia pseudotuberculosis Birds often found dead, loss of weight, digestive and respiratory signs can be seen Lesions

– Pale yellow nodules of caseous granulomas in liver, spleen, intestine, lung, air sacs, bone, muscle, etc.

– Gross lesions can be confused with mycobacteriosis or coligranuloma – Necrosis and inflammation associated with large numbers of Gram negative bacteria

Riemerella anatipestifer Previously classified as Pasteurella anatipestifer

– Disease called new duck disease, goose influenza Disease of young domestic ducks, geese and turkeys Respiratory signs, ocular discharge, diarrhea, neurological signs, as much as 10% mortality Fibrinosuppurative airsacculitis, pericarditis, perihepatitis, meningitis, uveitis, etc.

– Skin and joints may be involved

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Staphylococcosis Systemic infection of birds caused by S. aureus

– Less commonly by S. epidermidis and S. hyicus S. aureus most common in turkeys and broiler chickens, but has been isolated from a variety of

other bird species Lesions: omphalitis, pneumonia, synovitis, arthritis, osteomyelitis, green liver, gangrenous

dermatitis, cellulitis, endocarditis, abscesses (bumblefoot), etc. – Lesions in lungs can be similar to aspergillosis in turkeys

Streptococcosis Systemic infection of a variety of birds caused by species of genus Streptococcus

– S. zooepidemicus, septicemia in chickens, turkeys, pigeons, wild birds, etc. Valvular endocarditis with secondary infarcts in heart, liver, spleen, etc. Others: osteomyelitis, arthritis, tenosynovitis, salpingitis

– Streptococcus gallolyticus subsp. gallolyticus (previously S. bovis), septicemia in chickens, turkeys, pigeons, goslings, etc.

– S. faecium, septicemia in ducklings, goslings, chickens, etc. – Enterococcus hirae, encephalomalacia with vascular thrombosis and meningitis in broiler chicks – Enterococcus faecalis, associated with amyloid arthropathy in chickens (Brown Leghorns) – Enterococcus cecorum, associated with spondylitis, osteomyelitis and septicemia in chickens

Coxiella

Described in various species of Psittacines and a Toucan Severe hepatitis, splenitis, pneumonia, nephritis, encephalitis, etc. Small basophilic coccoid organisms in the cytoplasm of macrophages 96 – 97 % relationship to Coxiella burnetii

Miscellaneous bacteria a. Gallibacterium anatis biovar hemolytica (previously Pasteurella hemolytica) – has been associated

with septicemia including peritonitis and salpingitis in chickens, respiratory and other diseases in turkeys and other species of birds..

b. Pseudomonas aeruginosa, Klebsiella pneumoniae - can cause localized or systemic infection in poultry and other birds.

c. Burkholderia (Pseudomonas) pseudomallei has been associated with septicemia in psittacines. d. Bordetella hinzii has been associated with tracheitis in chickens and turkeys. e. Long segmented filamentous bacteria (LSFO) – associated (?) with enteritis in turkeys, chickens,

quail, psittacines, etc. f. Bacillus anthracis - been reported in ostriches as a cause of septicemia g. Listeria monocytogenes - can cause septicemia, myocarditis and encephalitis in chickens, septicemia

in psittacines and canaries but brain and heart not involved h. Aeromonas hydrophila can cause septicemia in poultry, ostriches, etc. i. Campylobacter jejuni - been associated with enteritis and hepatic necrosis in ostriches j. Lawsonia intracellulare - associated with enteritis in ratites k. Eubacterium tortuosum - granulomas in liver and spleen, broiler chickens and turkeys l. Nocardiforms – been associated with pectenitis in Lorikeets m. Neisseria-like bacteria have been associated with respiratory disease in turkeys, chickens, ostriches.. n. Sarcina – are Gram positive bacteria in the family Micrococcacae, found in pairs or tetrads

commonly in the ceca of poultry, significance unknown. Has been associated with abomasal bloat in ruminants and gastroenteritis in humans.

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o. Simonsiella (Alysiella) – belongs to Neisseriaceae family, gram negative bacteria with unique morphology; filamentous with transverse striations, commonly found in the oral cavity of chickens, significance unknown. In mammals has been associated with oral ulcers

p. Spirochetosis: Borrelia anserina, septicemia in poultry (ducks, geese, chickens, turkeys, pheasants) and canaries Borrelia related to B. hirmsii associated with hepatitis, splenitis and encephalitis in Northern Spotted

Owl. Borrelia sp. associated with relapsing fever in African penguins. Serpulina hyodysenteriae associated with typhlitis in rheas, in poultry? Serpulina piloscholi in ceca of pheasants, disease? Brachispira pilosicoli in ceca of chickens, game birds, turkeys, etc.

Fungal diseases a. Aspergillosis One of the most common fungal diseases of poultry, water fowl, psittacines, passerines, ratites,

raptors, zoo birds (penguins), etc. Aspergillus fumigatus and A. flavus most common

– Others: A. niger, A. terreus, A. glaucus, etc. A. niger is a black mold that can produce oxalic acid which can be seen in the tissues

especially in the walls of the blood vessels like in lungs. Respiratory signs (brooder pneumonia in poultry), unthrifty, diarrhea, neurological signs, ocular

involvement, sudden death, etc. Lesions

– Pale yellow nodules in lungs, air sac, syrinx, sinus, liver, brain, cloudy cornea, heart, etc. – White plaques with fuzzy green or grey or blue material (conidiophores- ‘fruity’ bodies) on air

sacs, pleura, etc. – Fibrinosuppurative or granulomatous pneumonia, airsacculitis, syringitis, sinusitis, encephalitis,

ophthalmitis, vasculitis, aortitis (aortic rupture), hepatitis, osteomyelitis, pericarditis, myocarditis, blepharoconjunctivitis, nephritis, etc.

b. Candidiasis Common mycosis of the upper digestive tract

– Also called thrush, crop mycosis, moniliasis – Young birds most susceptible

Candida albicans most common etiology Poultry especially in turkeys, psittacines, passerines, ratites, raptors, pigeons, water fowl, etc. Oral cavity, esophagus and crop involved with white proliferative plaques

– Proventriculus, gizzard, intestine less often involved – Systemic and ocular candidiasis have been described

Candida glabrata (Torulopsis) – Associated with hyperkeratosis of the skin in various species of birds

c. Zygomycosis In ostriches, psittacines, water fowl, canaries involving proventriculus and gizzard and air sacs in a

pigeon – Mucor sp, Absidia sp. and Rhizopus sp. isolated – necrotizing lesions with granulomatous reaction

d. Favus (avian ringworm) Due to Microsporum gallinae, dermatophyte of chickens with white powdery material on head, face

and eyelids

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Acanthosis, hyperkeratosis, dermatitis, folliculitis, etc. e. Ochroconis (Previously Dactylariosis) Due to O. gallopava in turkeys and quail Fibrinosuppurative encephalitis and ophthalmitis f. Cryptococcosis Due to C. neoformans in psittacines, pigeons, pheasant, kiwis and experimental infection in chickens Other species, Crytpococcus bacillosporus, C. neoformans var. gattii and C. neoformans var. grubii Sinusitis, laryngitis, tracheitis, encephalitis, hepatitis, pneumonia, dermatitis, stomatitis, retrobulbar

space, etc. g. Macrorhabdus ornithogaster (previously known as Megabacteria) an ascomycetous yeast. Been associated with proventriculitis in psittacines, passerines, ostriches, poultry, etc. h. Others fungal diseases Pythiosis

– Pythium insidiosum, associated with cutaneous ulcerative lesions in a White-faced Ibis – Multifocal necrotizing eosinophilic granulomatous inflammation

Malassezia – Malassezia sp. has been associated with dermatitis and follicultis in pet and exotic birds

Rhodotorula – R. mucilaginosa and R. glutens have been associated with ulcerative dermatitis in chickens

Histoplasmosis - due to H. encapsulatum – Granulomatous iridocyclitis in experimental infection of chickens

Penicillium – Penicillium griseofulvum, systemic infection in a toucanet – P. cyclopium, beak infection in a macaw – Penicillium sp. isolated from lungs of turkeys with granuloma’s resembling aspergillosis

Trichosporon – Trichosporon beigelii, granulomatous pneumonia, myocarditis, hepatitis in a macaw

Curvularia – Curvularia geniculata, mycetoma in a parrot

Scedosporium – Scedosporium prolificans isolated from feet of an ostrich with severe hyperkeratosis

Geotrichum and Paecilomyces – Geotrichum candidum and Paecilomyces variota have been isolated with disease

Viral diseases Diseases caused by herpesvirus, retrovirus, coronavirus, paramyxovirus, orthomyxovirus, picornavirus,

poxvirus, birnavirus, parvovirus, adenovirus, reovirus, enterovirus, astrovirus, circovirus, papovavirus, arbovirus, Bunyavirus, Bornavirus and other miscellaneous viruses

a. Marek’s Disease One of the most common and well studied diseases of young chickens

– Quail and turkeys are also susceptible – Etiology: cell-associated alpha herpesvirus

Pathogenesis: virus replicates in feather follicle epithelium, infection through respiratory route, viremia infection of B cells cytolysis infection of activated T cells cytolysis immunosuppression infection of other organs like nerves (paralysis) & blindness latency transformation of T cells (CD4) lymphoma

Lesions

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– Gross: bursal and thymic atrophy, swollen peripheral nerves, enlarged organs with pale white tumors in liver, spleen, kidney, lung, proventriculus, intestine, heart, gonads, thymus, irregular/gray iris, prominent feather follicles, etc.

– Microscopic: lymphoid necrosis and depletion in bursa, and thymus, neuritis, encephalomyelitis, pleomorphic to uniform T cell lymphocytic lymphoma in various organs Intranuclear inclusion bodies in feather epithelium Intranuclear inclusions also in other cells such as macrophages, reticular cells, lymphocytes;

bursa of Fabricius, eye, spleen, proventriculus, duodenums, colon, kidney, thymus, etc. Atherosclerosis can be produced with MD virus

b. Leukosis/Sarcoma Group Genus, ALV- related viruses of family Retrovirus

– Six subgroups; A, B, C and D (exogenous viruses), E (endogenous) & J (recombinant) A, B and J are common in the field, C and D are rare

– Various oncogenes have been identified (see table 1) They can produce a variety of neoplasms in chickens Influenced by strain of virus, dose, route of inoculation, age of host, genotype and sex of host Neoplasms: sarcoma’s (fibro, osteochondro, myxo, histio, lympho, hemangio), meningioma,

mesothelioma, erythroblastosis, myeloblastosis, nephroblastoma, granulosa cell tumor, hepatocellular carcinoma, glioma, (osteopetrosis), etc.

Multicentric histiocytosis or histiosarcoma in broiler chickens has been associated with J virus infected at hatch but not in immunotolorized chickens (different mechanism- see transmission below in LL)

Lymphoid Leukosis (LL) – Disease of semi mature and mature chickens – Etiology: retrovirus of leukosis/sarcoma group

Exogenous viruses, subgroups A, B, C and D – Transmission

Horizontal, transient viremia, immunity, LL rare Egg transmission, chronic viremia, immune tolerance, LL common

– B cell lymphoma in various organs, bursa of Fabricius, liver, spleen, kidney, gonads, etc. – Osteopetrosis – thickening of long bones

Effect of virus on osteoblasts Myelocytomatosis

– Neoplastic disease primarily of broiler breeders and broilers – Etiology: retrovirus, subgroup J (leukosis/sarcoma group) – Lesions: liver, spleen, kidney, sternum, etc., with nodules made up immature granulocytes – Hemangiosarcoma, histiocytoma, myxoma, carcinoma in liver, fibrosarcoma, lymphoma,

ganglioneuroma, renal tumors, etc., have also been associated with subgroup J virus Reticuloendotheliosis

– Includes runting syndrome, chronic lymphoma and acute reticulum cell sarcoma – Primarily in chickens and turkeys but neoplasia associated with REV has been observed in quail,

ducks, pheasants, geese and peafowl – Etiology: retrovirus of REV group, distinctly different from leukosis/sarcoma group, more closely

related to murine leukemia virus – Other viruses in REV group include chick syncytial virus, duck infectious anemia virus, spleen

necrosis virus and others

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– Lesions In runting syndrome: thymic and bursal atrophy, neuritis, lymphoma (similar to Marek’s

disease) In chronic lymphoma: bursal and visceral lymphoma (similar to Lymphoid Leukosis) In acute reticulum cell sarcoma: enlarged liver, spleen, kidney, heart, gonads, etc.

c. Infectious laryngotracheitis (ILT) Acute viral respiratory disease of primarily chickens

– Pheasants and peafowl are also susceptible Etiology: Gallid herpesvirus 1. Lesions: oculonasal discharge, trachea with hemorrhage and/or fibrinous exudate

– Conjunctivitis, tracheitis, bronchitis and sinusitis with intranuclear inclusions. Syncytia formation with intranuclear inclusion bodies is characteristic.

d. Infectious Bronchitis Highly contagious viral respiratory disease of young chickens

– Drop in egg production and poor egg quality (poor shell and thin albumen) in layers Etiology: coronavirus, many serotypes, and great antigenic variation among strains of virus Lesions: catarrhal tracheitis, conjunctivitis, bronchitis, and airsacculitis

– Fibrinosuppurative inflammation in cases complicated with E. coli – Interstitial nephritis with nephrotropic strains

e. Avian Paramyxoviruses Based on antigenic relatedness (HI test) avian paramyxoviruses are classified into nine groups

Groups Primary Host Other Hosts

APMV-1/Newcastle Disease Virus

numerous many

APMV-2/Yukaipa Passerines, turkeys Chickens, psittacines, rail APMV-3/Turkeys Turkeys None (chickens?) APMV-3/Psittacines Psittacine Passerines APMV-4/Duck Ducks Geese, rails APMV-5/Budgerigar Budgerigar none APMV-6/Duck Ducks, geese Turkeys APMV-7/Dove Pigeons, dove none APMV-8/Goose Ducks, geese none APMV-9/Duck Ducks none

Newcastle Disease

– Acute viral disease of chickens, turkeys, pigeons, doves, pheasants, ratites, psittacines, cormorants, etc. 236 species of birds comprising 27 orders

– Etiology: avian paramyxovirus - 1, isolates vary greatly in pathogenicity to chickens Lentogenic: mild or inapparent infection in chickens Mesogenic: cause disease and mortality in young chickens Velogenic (viscerotropic and neurotropic): lethal infection of chickens of all ages Present OIE classification based on chick intra-cerebral pathogenicity index (ICPI)

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ICPI of > 0.7 is Newcastle disease virus (formerly Velogenic and mesogenic) ICPI of < 0.7 is Avian Paramyxovirus –1 (formerly Lentogenic)

– Clinical signs Vary with strain, respiratory, digestive, ocular, neurological, sudden death In mature chickens, egg production and quality problems (mesogenic strain)

– Lesions In pigeons: enteritis, pancreatitis, nephritis, encephalitis, otitis interna, respiratory system

rarely involved In chickens; tracheitis, pneumonia, enteritis, conjunctivitis, encephalitis, myocarditis,

lymphoid necrosis Velogenic; hemorrhages in conjunctiva, trachea, oral cavity, esophagus, proventriculus,

ceca, rectum Disseminated vasculitis, lymphoid necrosis and depletion, mucosal necrosis and ulceration Inclusions are rare but both intranuclear and intracytoplasmic inclusions have been

described In one case, discrete eosinophilic intranuclear and intracytoplasmic inclusions in conjunctiva,

esophagus, lung, brain, adrenal ganglia of a pheasant and in the brain of a chicken with NDV Eosinophilic intranuclear inclusions in hepatocytes in doves associated with lentogenic type

of NDV

Other Avian Paramyxoviruses – APMV - 2 (Yucaipa):

Respiratory disease in young turkeys and drop in egg production in layers, chickens are susceptible

– APMV - 3, two strains, turkey and psittacine Turkey: egg production drop in turkeys Psittacine; neurological and digestive problems in psittacines and passerines Encephalitis with intranuclear and intracytoplasmic inclusion bodies in neurons and glial

cells Myocarditis, pancreatitis with intranuclear inclusions

– APMV -5 (Kunitachi): Enteritis and mortality in budgerigars and lorikeets

f. Avian metapneumovirus – Cause of Turkey Rhino Tracheitis (TRT) of turkeys, Swollen Head Syndrome (SHS) of chickens,

highly contagious respiratory diseases – Etiology: pneumovirus (Paramyxoviridae) – Lesions: swollen sinuses, sinusitis, tracheitis, rhinitis, conjunctivitis

g. Avian Influenza

Acute viral disease of poultry; turkeys and chickens and psittacines, passerines, ratites, etc. – It has been isolated from many species of birds – Waterfowl and shore birds serve as reservoirs Etiology: type A influenza virus of family Orthomyxoviridae – Numerous subtypes based on surface antigens, hemagglutinin (16) and neuraminidase (9)

Viruses of H5 (H5N2) and H7 (H7N1) subtypes are considered highly pathogenic. Low pathogenic H5 and H7 subtypes do exist but have the potential to change to highly pathogenic subtypes

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H1N1 (swine flu) and novel H1N1 in turkeys – drop in egg production H4N8, H4N6, H3N8 in exotic birds H5N1 (bird flu); gallinaceous birds including chickens, turkeys, quail, pheasants, partridges,

Guinea fowl are highly susceptible Humans are susceptible Numerous other bird species are also susceptible; Bar headed geese and other geese,

ducks, swan, flamingos, gulls, egrets, herons, pigeons, crows, sparrows, starlings, magpies, finches, emus, budgerigars, ostriches, etc.

H5N1 first identified in Hong Kong in 1997 but was present in China in 1996 Since 2002 outbreaks in Asia, Europe and Africa

Clinical signs: varies greatly with pathogenicity; none to respiratory, digestive, ocular, neurological, sudden death, etc. – Drop in egg production in layers Lesions: vary greatly in pathogenicity – Mildly pathogenic: catarrhal tracheitis, sinusitis, airsacculitis, conjunctivitis, pneumonia,

peritonitis, oophoritis, salpingitis, etc. – Highly pathogenic: hemorrhagic lesions in skin of face, comb & shanks and GI tract, interstitial

pneumonia & nephritis, encephalitis, conjunctivitis, myocarditis, adrenalitis, pancreatitis, myositis, lymphoid necrosis, vasculitis and thrombosis, etc.

h. Avian Encephalomyelitis Viral disease of young (1-3 weeks) chickens, turkeys, pheasants and coturnix quail – Neurological signs (epidemic tremor) – Drop in egg production in layers – Egg transmitted – Etiology: Picornavirus (genus: Tremovirus) Lesions: neuronal swelling, central chromatolysis, lymphocytic perivascular cuffing, gliosis in brain and lymphocytic foci in muscular layer of proventriculus and gizzard, pancreatitis, myocarditis, myositis, peripheral neuritis, etc. – A few survivors can develop cataracts later

i. Avian Pox

Slow spreading viral disease of chickens, turkeys, quail, pigeons, canaries, raptors, psittacines, ostrich, peacock, waterfowl, etc.

– 60 species of wild birds Etiology: poxvirus of genus Avipoxvirus, many strains – Fowl pox, turkey pox, pigeon pox, canary pox, quail, mynah, psittacine, junco, sparrow, starling,

etc. Signs: cutaneous, respiratory, digestive, ocular – Septicemic form in canaries, 70 - 90% mortality Lesions – Gross:

Dry pox or cutaneous form: proliferative skin lesions on face, eyelids, beak, feet, legs, vent, etc.

Wet pox or diphtheritic form: yellow raised plaques in sinus, trachea, oral cavity esophagus/crop, conjunctiva, etc.

– Micro:

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Proliferation of epithelial cells, ballooning degeneration with eosinophilic intracytoplasmic inclusion bodies (pathognomonic)

Pneumonia in canaries. Others: spleen, bone marrow, thymus, bursa, air sacs, dermis, etc. Some avipoxviruses are oncogenic, wart-like growth

j. Infectious Bursal disease (IBD) Acute viral disease of young chickens (1-6 weeks) and secondary immunosuppression Turkeys and ducks, subclinical infection Etiology: birnavirus Lesions: enlarged and edematous bursa of Fabricius some times with hemorrhages and atrophy in

later stages, hemorrhages in skeletal muscle, thymic atrophy with virulent IBD, hemorrhages most of the times in the bursa with very virulent (vv) IBDV – Lymphoid necrosis and depletion – May or may not be hemorrhages with vv IBDV – Secondary infections with inclusion body hepatitis, gangrenous dermatitis, bursal

cryptosporidiosis, etc. k. Chicken Infectious Anemia (CIAV) Viral disease of young chickens characterized by aplastic anemia and immunosuppression Chicks 1-3

weeks of age most susceptible Vertically transmitted Etiology: a circovirus, genus Gyrovirus, family Circoviridae Hematology: anemia, hematocrit less than 27% (N 35%), leukopenia, thrombocytopenia

– Due to cytotoxic effect of virus on bone marrow precursor cells Lesions: pale bone marrow, severe thymic atrophy, atrophy of bursa, hemorrhages in skeletal

muscles Lymphoid necrosis and depletion, bone marrow hypoplasia

– Gangrenous dermatitis, colibacillosis, aspergillosis, viral infection, etc. Eosinophilic (red) intranuclear inclusions in mononuclear inflammatory cells (macrophages?) of

thymus, spleen, bone marrow, bursa, lung, etc. in some cases – True nature of these inclusions is not known

l. Duck Viral Enteritis (DVE) Acute viral disease of primarily adult ducks, geese and swans characterized by high mortality Etiology: herpesvirus Lesions: hemorrhages on heart, liver, gizzard, fibrinonecrotic lesions in esophagus, rectum, cloaca,

bursa, annular band of hemorrhage and necrosis in intestine, ceca, and thymic atrophy – Necrosis, inflammation and intranuclear inclusions in liver, intestine, thymus, gland of Harder,

conjunctiva, etc. – Esophagitis and bursal necrosis with intranuclear and intracytoplasmic inclusions in mucosal

cells

m. Duck virus hepatitis (DVH) Peracute viral infection of ducklings (< 5 weeks) characterized by high mortality Etiology:

– DVH - 1, picornavirus (DVHA) – DVH - 2, astrovirus – DVH - 3, astrovirus

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Lesions: petechiae or ecchymotic hemorrhages and necrosis in liver, minimal inflammation

n. Parvovirus Infections Goose parvovirus (Derzsy’s disease): highly contagious disease of young geese and Muscovy ducks

– Serofibrinous pericarditis and perihepatitis – Myocarditis with intranuclear inclusions

Muscovy duck parvovirus – Serologically related to goose parvovirus – Causes locomotor problems with high mortality in 1-3 weeks-old ducks, loss of weight , pale leg

muscles, serofibrinous pericarditis and perihepatitis Myositis, myocarditis, encephalomyelitis, neuritis, etc.

– Ascites, round hearts in ducks recovered from infection

o. Avian Reoviruses Causes disease in chickens, turkeys, ducks, geese, psittacines, etc. - Chickens and turkeys: arthritis and proliferative tenosynovitis, enteritis, myocarditis, thymic and

bursal atrophy. Encephalitis in chickens. - Ducks and geese: tenosynovitis, pericarditis, myocarditis, bursal and thymic atrophy - Psittacines: hepatitis and splenitis.

p. Avian Adenoviruses Three groups:

– Group I - quail bronchitis, inclusion body hepatitis and hydropericardium syndrome in chickens, also disease in turkeys, pigeons, psittacines, raptors, etc.

– Group II - hemorrhagic enteritis virus of turkeys (HEV), marble spleen disease of pheasants (MSD) and splenomegaly of chickens

– Group III - egg drop syndrome of chickens with no apparent lesions but caused tracheitis and bronchitis in goslings

Quail bronchitis – High mortality in young bobwhite quail associated with bronchopneumonia, tracheitis, hepatitis,

pancreatitis, bursal necrosis, intranuclear inclusions Inclusion body hepatitis of chickens, also in turkeys, guinea fowl, pigeons, psittacines, etc.

– In chickens usually secondary to immunosuppression caused by IBDV, CIAV – Liver enlarged and mottled red/pale, foci of necrosis, inflammation and intranuclear inclusion

bodies, also pancreatitis – Similar lesions seen in turkey poults, guinea fowl, pigeons – Hepatitis, enteritis, bronchitis, pancreatitis, nephritis, encephalitis, etc., associated with

intranuclear inclusions in psittacines Hemorrhagic enteritis virus (HEV) of turkeys and Marble spleen disease (MSD) of pheasants

– Caused by group II adenovirus – Guinea fowl, psittacines, (partridge) susceptible – Young turkeys (4-12 weeks) and pheasants (3-8 months) – With HEV, intestinal hemorrhage and enlarged mottled white spleen and immunosuppression

Intranuclear inclusions in mononuclear cells of spleen and intestine, renal epithelial cells in HEV

– In pheasants mottled white enlarged spleen, MPS cell hyperplasia, intranuclear inclusions – Splenomegaly in chickens

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q. Enteritis Poult enteritis Disease of young turkeys, multiple etiologies such as viruses, bacteria, protozoa Viruses include coronavirus (blue comb disease), enterovirus, rotavirus, astrovirus, reovirus, etc.

AEEC can play significant role Diarrhea, loss of weight, small intestine and ceca distended with watery or frothy contents Mortality 1 - 55%, caseous exudate in bursa with coronavirus infection and AEEC infection Increased cellularity of lamina propria, necrosis of cells in lamina propria and enterocytes, villus

atrophy, lymphoid necrosis in thymus and bursa (virus?) Runting Stunting Syndrome in (RSS) chickens

– Failure to gain weight or thrive normally in chicks – Clinical signs, pathology, etiologies (rotavirus, astrovirus, reovirus) very similar to poult enteritis – Cystic enteritis; crypt necrosis and dilation, increased cellularity of the lamina propria, atrophy

of villi have been observed in 1 to 3 week-old chicks Enteritis associated with rotavirus and enterovirus has also been described in young pheasants,

quail, chukars, etc.

r. Herpesviruses (Marek’s disease, see page 16) Psittacine Herpesvirus

– Diverse group of viruses which infect a variety of psittacines – Four genotypes (Psittacid Herpesvirus 1, 2, 3 and 4) and three serotypes are known – More than four genotypes may exist such as Bourke’s Parakeet Herpesvirus – According to one classification three diseases are known but this may change

PACHECO’S DISEASE Acute viral disease of a variety of psittacines (common in 1980’s in US) Lesions:

Enlarged liver occasionally with petechiae, enlarged spleen, fluid filled intestine, diphteritic membrane in oral cavity, esophagus, etc.

liver necrosis with or without inflammation, enteritis, stomatitis, esophagitis, pancreatitis, conjunctivitis, splenic and bursal necrosis, nephritis with intranuclear inclusion bodies

syncytia formation with inclusions in liver AMAZON TRACHEITIS, disease characterized by tracheitis, bronchitis, rhinitis, laryngitis with

syncytia formation and intranuclear inclusions Virus has some cross reactivity with ILT virus of chickens Similar lesions such as in Amazon tracheitis has been observed in Rosy Bourke parakeets

associated with a novel herpesvirus BUDGERIGAR HERPESVIRUS, rare disease associated with decreased hatchability and “feather

duster” plumage Herpesvirus in cutaneous tissue (with intranuclear inclusions) has been identified in

psittacines Herpesvirus sequences have been demonstrated in cloacal Papilloma’s of psittacines

Miscellaneous Herpesviruses – GOOSE HERPESVIRUS

Lesions like in Duck viral enteritis with intranuclear inclusion bodies and high mortality in goslings

– PIGEON HERPESVIRUS (COLUMBID HERPESVIRUS – 1)

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Common in young squabs characterized by hepatitis, pancreatitis, esophagitis associated with intranuclear inclusions

Conjunctivitis, enteritis, myocarditis, encephalitis, laryngitis, splenitis, etc. can also be seen Raptors and budgies are susceptible

– FINCH HERPESVIRUS Disease of primarily Gouldian finches characterized by high mortality, conjunctivitis,

tracheitis, bronchitis, associated with cytomegalic cells and intranuclear inclusions – OTHERS HERPES VIRUSES OF OWLS, FALCONS, EAGLES, CRANES, etc.

Hepatitis associated with intranuclear inclusion bodies Viruses not well characterized

- Herpesvirus sequences have been identified in cloacal papillomas of psittacines - Herpesvirus has been identified in an Indian Gyps Vulture

s. Psittacine Beak and Feather Disease Viral disease of many species of psittacines characterized by chronic feather and beak dystrophy

– Acute immunosuppression and sudden death in young birds due to secondary bacterial septicemia and fungal infections

Etiology: Psittacine circovirus, genus circovirus, family Circoviridae – Psttacine circovirus 2 in Lorikeets

Other genotypes exist Clinical signs: dystrophic feathers first noticed of the powder down, progress to contour feathers,

followed by primary, secondary tail and crest feathers, almost symmetrical – Dystrophy of the beak

Lesions – Gross: abnormal and loss of feathers, sloughing of claws, beak necrosis, necrosis of oral mucosa,

liver, bursa, thymus, etc. – Microscopic: pterylitis and pulpitis associated with botryoid inclusions in macrophages, also in

bursa, bone marrow, thymus, beak, claws, liver, pancreas, thyroid, testes, etc. Intranuclear inclusions in feather epithelium, intestine, esophagus, hepatocytes

– Liver necrosis and inclusions in bursa of Fabricius in African Grays Pigeons and doves

– Etiology: Pigeon circovirus, genus circovirus – Feather dystrophy, exudate in bursa (due to bacterial infection), pterylitis, bursal lymphoid

depletion and intracytoplasmic circovirus inclusions in macrophages of bursa of Fabricius, spleen, thymus, cecal tonsil, etc.

– secondary bacterial, parasitic, fungal and other concurrent viral infections common Canaries and Finches

– Etiologies: Canary and Finch circoviruses, genus circovirus, family Circoviridae – Feather dystrophy and characteristic circovirus inclusions in bursa of Fabricius in finches – In canaries intracytoplasmic inclusions in smooth cells of the muscular layer of the intestine,

arteries of spleen and pancreas Gulls, Geese, Ducks, Ravens, Starlings, Pheasants are also susceptible to circovirus

– Circovirus inclusions in the bursa of Fabricius in gulls, geese – Feather abnormalities in ducks and ravens

t. Papovavirus Two genera are known to cause disease in psittacines and passerines

– Papillomavirus

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– Polyomavirus Papillomavirus

– It has been associated with cutaneous papillomas in wild finches (Fringilla) and in African Grey Parrots

– Herpesvirus sequences have been associated with cloaca papillomas in psittacines Polyomavirus Three groups, A, B and C

– Causes BUDGERIGAR FLEDGLING DISEASE (BFD) One of the most common diseases of psittacines (disease of 90’s?) and passerines Antibodies to BFDV been detected in chickens, but chickens are resistant to infection

Etiology: polyomavirus, different strains such as psittacine, passerine, etc., may exist Variety of psittacines and passerines (finches, canaries, seed crackers and blue bills). Buzzards, Aracaris and Falcons are also susceptible Young psittacines are highly susceptible with very high mortality (30 - 100%) but adults

are also susceptible Feather dystrophy in budgerigars, acute death, digestive, neurological, respiratory signs,

etc. Lesions Gross: variation among psittacines and also passerines

In most of psittacines feather dystrophy, hemorrhages in skin, subcutis, skeletal muscle, heart, and intestine, liver enlarged and mottled red or with white foci, splenomegaly, pale kidneys, ascites, lung congestion, pale carcass, etc.

In passerines, liver enlarged and mottled white, serosal or subserosal hemorrhage of intestine, pale myocardium, etc.

Microscopic: hemorrhages in various organs, necrosis in spleen, bursa, thymus and bone marrow, mid zonal or random necrosis in liver, myocarditis, enteritis, nephritis, membranous glomerulopathy, pancreatitis, conjunctivitis, encephalomyelitis, ganglionitis (spinal), etc.

Bluish karyomegalic inclusions in various tissues; epidermis, feather follicle epithelium, esophagus, kidney, macro/lympho of spleen, bursa, thymus, bone marrow, liver, etc., hepatocytes, myocytes, endothelial cells, glial cells, Purkinje cells, etc.

– Goose hemorrhagic polyomavirus: causes high mortality in 4-10 week old geese, 100 % mortality in one week-old geese subcutaneous edema, ascites, hemorrhagic enteritis, nephritis and lymphoid necrosis in

bursa of Fabricius

u. Proventricular Dilatation Disease (PDD) A common primarily a chronic disease of psittacines (>80 species) known since 1970’s. Been called

by many names. Budgerigars may be resistant and chickens and ducks are not susceptible. – Dilation of the proventriculus (not always), anorexia, regurgitation, passing of undigested seeds

in feces, diarrhea, neurological signs, loss of weight, etc. PDD has also been reported in a Peregrine Falcon, Red Tail Hawk, Golden Eagle, Canada geese*,

Trumpeter Swans*, Ostriches*, Toucan, Finches, Canaries*, Bearded Barbet, Spoon Bill, Honey Creeper, Long-wattled umbrella bird, Mouse bird, etc.

* Species in which ABV has been demonstrated. Etiology: Avian Bornavirus (ABV), many genotypes; ABV1 to ABV6. Canary and C. geese distinctly

different from known ABV’s.

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– Falcon, Hawk, Eagle, Toucan and Mouse bird with PDD-like lesions have been negative for ABV by PCR.

– ABV is distinct from Borna Disease virus (BDV) of ungulates, 65 % homology – ABV can also be found in non-neural tissues and also in non-symptomatic birds

Lesions – Gross: dilated thin proventriculus in 70% of cases, distended duodenum, emaciation, etc. – Microscopic: lymphoplasmacytic ganglioneuritis of splanchnic nerves of crop/esophagus,

proventriculus, gizzard, intestine, adrenalitis, myocarditis, neuritis, encephalomyelitis, choroiditis, retinitis, etc. (see table 2)

– Unusual lesions of lymphoid foci or nodules in visceral organs has also been reported

v. Miscellaneous Viral Diseases Turkey viral hepatitis

– Disease of young turkeys – Etiology: 25 - 30 nm virus (Novel Picornavirus) – Liver and pancreas with foci of necrosis and inflammation, syncytia in liver

Avian nephritis – Highly contagious disease of chickens – Etiology: Astrovirus – Pale and enlarged kidneys with increased urates – Nephritis and secondary visceral urate deposition

Hepadna virus (hepatitis B virus) – Common in ducks, but no significant clinical disease or lesions – Also in swans and geese, no associated clinical disease

Avian Hepatitis E virus

– Hepevirus - Hepeviridae – Has been associated with hepatitis-splenomegaly syndrome in mature chickens – Disease is called big liver and spleen disease (BLSD) in Australia – Drop in egg production and increased mortality – Periportal hepatitis, vasculitis, necrosis and hemorrhage in liver. Spleen with increased number

of MPS cells with amyloidosis frequently Chicken Proventricular Necrosis Virus (CPNV)

– Novel birnavirus (different from IBD virus) – Has been associated with transmissible proventriculitis primarily in young broiler chickens – Necrosis of glandular epithelium, lymphocytic inflammation in the glands and mucosa, ductular

hyperplasia and lymphoid nodule formations Louping ill virus

– Red grouse are susceptible Arboviruses

– WEST NILE VIRUS Etiology: Flavivirus First appeared in people in the US in NY city in 1999, flu-like symptoms, 7/61 died

Spread to West coast in 2003 and is endemic now in US

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Over 14 orders and over 325 species of birds are susceptible but most severe in crows, blue jays, geese, herons, raptors (owls, hawks), etc.

Others; pigeons, kestrels, gulls, storks, geese, magpie, bald eagles, ducks, flamingos, rosella, lorikeets, Australian parakeets, cockatoo, conures, cockatiel, etc.

Among psittacines Rosella’s and other Australian Parakeets and Lorikeets are most susceptible

Chickens and turkeys are resistant to infection except for a report in a wild turkey Clinical signs vary from sudden death to depression, weight loss, ataxia, tremors,

opisthotonus, impaired vision, etc. Gross: variable depending on the species affected. Hemorrhages in brain in some corvids,

pale areas in the myocardium especially in raptors , enlarged liver and spleen, nephritis, hemorrhage and necrosis in the intestine

Histo: variable, primarily nonsuppurative encephalitis and myocarditis in corvids and raptors. Others include hepatitis, splenitis, pancreatitis, enteritis, nephritis, adrenalitis, feather folliculitis (pterylitis) and pulmonary hemorrhage. Some birds may not have any lesions especially in acute stages.

Virus widespread in many tissues but kidney and brain are good for virus isolation – USUTU VIRUS (Flavivirus)

Encephalitis, myocarditis, hepatic necrosis in Eurasian Black birds (Austria). Great grey owls and Barn swallows are also susceptible.

– EASTERN EQUINE ENCEPHALOMYELITIS VIRUS (TOGAVIRUS) Causes neurological signs and encephalitis in pheasants, partridges, finches, raptors and

turkeys In young turkeys and chickens, myocarditis, lymphoid necrosis in bursa and thymus Hemorrhagic enteritis and splenic necrosis in emus Been associated with serositis, epicarditis and myocarditis, interstitial pneumonia, hepatic

necrosis, lymphocytic proventriculitis, etc., in psittacines – WESTERN EQUINE ENCEPHALOMYELITIS VIRUS (TOGAVIRUS)

Encephalitis, myocarditis, hemorrhagic leiomyositis of intestine associated with vasculitis in emus

Encephalitis in pigeon and neurological signs in turkeys – HIGHLAND J VIRUS (TOGAVIRUS)

Encephalitis and myocarditis in partridges and young turkeys Associated with precipitous drop in egg production in turkeys

– BUGGY CREEK VIRUS (TOGAVIRUS) Encephalitis, myocarditis, myositis in nestling sparrows

– ISRAEL TURKEY MENINGOENCEPHALITIS VIRUS (TOGAVIRUS) Encephalitis and myocardial necrosis in 10-12 week-old turkeys

– BUNYA VIRUS (Turlock-like): Associated with encephalomyelitis and myocarditis in an ostrich chick

Parasitic diseases

Protozoa: coccidia, histomonas, cryptosporidia, sarcocystis, toxoplasma, atoxoplasma, amoeba, microsporidia, trichomonas, leucocytozoon, malaria, haemoproteus, parahaemoproteus, giardia, cochlosoma, spironucleus (Hexamita), balantidium, trypanosomes, hemosporozoa, besnoitia, chilomastix, caryospora, etc.

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Blastocystis is classified as protista (commonly found in the ceca of gallinaceous birds, significance unknown.

Nematodes: Ascarids, Capillaria, Syngamus, Tetrameres, Heterakis, Baylisascaris, etc. Cestodes: Raillietina, Davainea, Hymenolepis, etc. Trematodes: Prosthogonimus, Schistosomes, Sphaeridiotrema, etc. Arthropods: mites, fleas, lice, etc.

Protozoa a. COCCIDIOSIS Common disease of many species of birds caused by species of genera primarily Eimeria and

Isospora and are quite host specific Chickens: disease of universal importance

– Eimeria tenella (ceca), E. acervulina (upper small intestine), E. maxima and E. necatrix (mid small intestine)

– Hemorrhagic, mucoid, necrotic, proliferative enteritis – Numerous coccidia in different stages of development

Turkeys: common, lesions less severe than in chickens – E. adenoides (ceca), E. meleagrimitis (mid small intestine) – Mucoid enteritis, sometimes hemorrhagic and necrotic enteritis

Geese: E. truncata occurs in kidney – Nephritis and urate deposits – E. anseris causes enteritis

Ducks: renal coccidia due to E. boschadis, E. truncata, etc. – Intestinal Coccidiosis is not common in commercial ducks

Quail, partridges, and pheasants: various species of Eimeria causes enteritis – In quail coccidiosis is commonly associated with ulcerative enteritis caused by Clostridium

colinum Pigeons: E. labbeana causes enteritis Psittacines:

– Species of Eimeria, E. dunsingi and Isospora can cause enteritis in budgerigars, lories, parakeets, parrots, etc.

Passerines: – Finches: Isospora lacazei has been associated with enteritis

Cranes: – E. gruis and E. reichenowi causes granulomatous enteritis, hepatitis, splenitis, pneumonia,

myocarditis, etc. in whooping and sandhill cranes

b. HISTOMONIASIS Also called black head, a common protozoal disease of turkeys and partridges

– Also in chickens, peafowl, quail, pheasants, rhea, etc. Etiology: Histomonas meleagridis

– Cecal worm, Heterakis gallinarum and earth worms can act as accessory hosts Lesions: saucer shaped depressions (subacute to chronic lesions) or pale white foci (acute lesions) in

liver and fibrinonecrotic mucosa and thickened wall of ceca – Pale white nodules in the liver can resemble lymphoma sometimes – Granulomatous hepatitis and typhlitis associated with spherical protozoa, 8 - 21 um in diameter

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– Splenitis, nephritis, bursitis (bursa of Fabricius), pneumonia proventriculitis and ingluvitiis. Peritonitis secondary to perforating typhlitis can be seen in turkeys

– Protozoa have been demonstrated by IHC in various organs including brain

c. CRYPTOSPORIDIOSIS Common protozoa of various species of birds

– Chickens, turkeys, quail, ratites, ducks, pheasants, peafowl, psittacines, passerines, falcons, etc. C. baileyi, C. meleagridis, C. galli, C. parvum and probably others Infect various body systems

– Cloaca, bursa of Fabricius and trachea most common – Nasal cavity, sinus, bronchus, air sac, conjunctiva – Intestine, ducts of pancreas, salivary and esophageal glands and bile duct – Ureters, collecting tubules of kidney, middle ear – Proventriculus – C. galli in passerines

Inflammation and hyperplasia of epithelium

d. SARCOCYSTOSIS Systemic protozoal disease of psittacines caused by S. falcatula and others

– Opossum is the definitive host, cowbirds and grackles are intermediate hosts – Old World psittacines highly susceptible – Young new world psittacines, canaries, finches, pigeons are also susceptible – Gallinaceous birds and anseriformes are resistant

Sarcocystis with encephalitis has been described in a golden eagle, capercailles and chickens S. riley causes sarcocystosis in skeletal muscle (rice breast) of ducks, an innocuous incidental finding Lesions

– Pulmonary edema, congestion, liver may be enlarged and mottled white, splenomegaly – Lymphoplasmacytic interstitial pneumonia, edema and schizonts in capillaries – Myocarditis, hepatitis, splenitis, nephritis, encephalomyelitis, neuritis, myositis, uveitis, etc.,

associated with schizonts – Mature cysts in the heart and skeletal muscle

Generally no reaction to cysts in muscles Sarcocystis calchesi associated with severe meningoencephalitis and myositis associated with or

without cysts of Sarcocystis has been reported in pigeons in Germany and in N. Aemrica. Northern goshawk has been identified as the definitive host of S. calchesi.

e. TOXOPLASMOSIS Sporadic disease of various species of birds

– It has been described in passerines (canaries), chickens, psittacines, pigeons, ducks, penguin, Japanese quail, chukar partridges, etc.

– Turkeys, chickens, pheasants, Bob White quail, owls, house sparrows resistant Etiology: T. gondii Lesions: encephalomyelitis, ophthalmitis, pneumonia, myocarditis, hepatitis, splenitis, neuritis,

myositis, enteritis, adrenalitis, etc. associated with zoites and cysts – Optic nerve; may be enlarged and yellow with necrotizing and granulomatous neuritis in

chickens

f. ATOXOPLASMOSIS Common coccidian infection of canaries and finches, (previously called Lankesterella)

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– Also in mynah’s, sparrows, grosbeaks, thrush, cowbirds, raptors and many birds of order Passeriformes

Etiology: A. serini (Isospora serini), A. adiei and probably others. Taxonomy not clear. Lesions

– Liver enlarged with white foci, splenomegaly – Enteritis, hepatitis, myocarditis with arteritis, splenitis, myositis, dermatitis, pneumonia, etc.

Lesions resemble lymphoproliferative (positive for CD3) disease and an association with lymphoma has been proposed,

– Schizonts in cytoplasm of macrophages Lankesterella-like coccidia associated with pneumonia in a Northern Cardinal

g. MICROSPORIDIOSIS It can be a significant disease of psittacines It has been reported in a variety of lovebirds, budgerigars, parrots, cockatiels, etc.

– Also reported in ostrich and Hummingbirds – Encephalitozoon hellum, others?

Lesions: granulomatous nephritis, necrosis and inflammation in liver, enteritis, pneumonia, conjunctivitis, etc. associated with Gram-positive organisms

h. TRICHOMONIASIS A common infection of pigeons and raptors

– Also in canaries, finches, doves, psittacines, ducks, poultry, wild birds, etc. Etiology: Trichomonas gallinae

Tetratrichomonas anatis has been associated with sinusitis/rhintiis, tracheitis and enteritis and Tetratrichomonas gallinarum has been associated with typhlohepatitis in ducks Tetratrichomonas gallinarum in a mocking bird Tri/tetratrichomonas gallinarum are common in the ceca of chickens and turkeys - diarrhea

Lesions of Trichomonas gallinae – Granulomatous stomatitis, pharyngitis, esophagitis, ingluvitis, and enteritis – Hepatitis, pericarditis, airsacculitis, tracheitis, pneumonia, meningoencephalitis – Sinusitis, rhinitis, episcleritis – Salpingitis in ducks

i. LEUCOCYTOZOONOSIS Disease of anseriformes, turkeys, raptors, wild birds and columbiformes

– Black flies (Simuliidae) are vectors Etiology: L. simondi in anseriformes, L. smithi in turkeys, L. marchouxi in columbiformes, L. toddi in

falconiformes, L. ziemanni in owls – Infect both white and red blood cells

Lesions – Disseminated characteristic megaloschizonts in endothelial cells of liver, spleen, heart, brain,

eye with hepatitis, myocarditis, encephalitis, etc. L. caulleryi, which causes severe disease in young chickens in south and eastern Asia, is classified as

Akiba caulleryi – Vectors are biting midges of genus Culicoides – Lesions are similar to ducks

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Leucocytozoon-like infection has been described in budgerigars, parakeets, Nankeen kestrels and a buzzard – Myositis, myocarditis, encephalitis and hemorrhages in skin, pericardium, pancreas,

hepatosplenomegaly, etc. – Granulomatous meningoencephalomyelitis, pectenitis and proliferative arteritis associated with

endothelial parasitic cysts in Nankeen Kestrels

j. AVIAN MALARIA Hemoprotozoal infection of canaries, penguins and raptors caused by species of Plasmodium

– Ducks, pigeons, chickens, grouse, pheasants, sparrows, blackbirds, robin, canary, tern, etc. are susceptible

– Three species of Culicoides are vectors Etiology: P. relictum, P. elongatum, P. circumflexum, etc.

– Infect red blood cells and cells of MPS Lesions: anemia, interstitial pneumonia, hepatitis, splenitis, encephalitis, etc.

– Brown-black pigment (malaria pigment) of RBC’s in MPS cells

k. HAEMOPROTEUS Hemoprotozoa of some significance primarily in columbiformes

– Common in raptors, water fowl, passerines, etc. – Also seen in psittacines

Etiology: H. columbae in pigeons and doves – Biting flies of hippoboscids and Culicoides are vectors – Infects red blood cells and endothelial cells

Lesions: anemia, hepatitis, splenitis, myositis, pneumonia, etc. – Schizonts and megaloschizonts can be seen

Hepatic hemorrhage, hemocoelom and sudden death due to Haemoproteus infection in passerine birds – In oropendola, different species of tanagers, cardinal, birds of paradise – Hepatocellular necrosis associated with megaloschizonts

Disseminated myositis, myocarditis, splenitis, hepatitis, encephalitis, etc., associated with protozoa of Parahaemoproteus lophortyx is common in quail in California – Anemia and other organs can also be involved

l. GIARDIA, SPIRONUCLEUS (HEXAMITA) Giardia psittaci cause of enteric disease in budgerigars

– Others: cockatiels, lovebirds, parrots, conures, many wild birds, herons, egrets, sparrows, etc. Hexamita meleagridis an enteric protozoa of turkeys

– Others: pheasants, pigeons, quail, partridge, ostrich, peafowl, etc. Lesions

– Emaciation, fluid filled intestine, catarrhal enteritis

m. OTHER ENTERIC PROTOZOA Cochlosoma anatis/ Cochlosoma. sp., a flagellate enteric protozoon of small intestine is associated

with catarrhal enteritis in turkeys, ducks, geese and finches Entamoeba gallinarum common in large intestine of turkeys, significance? Others: Balantidium spp. in ostriches, Wenyonella philiplevinei in ducks, etc.

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n. MISCELLANEOUS PROTOZOA Amoeba of undetermined spp. associated with meningoencephalitis in a cockatiel Besnoitia: Cyst stages of Besnoitia-like protozoa causes arteritis and endarteritis in shore birds like

knots with severe mortality. Caryopsora: coccidia with raptor-mouse cycle. Cysts found in the intestine, and other organs.

Disease? Chilomastix: cyst forming flagellate seen in the intestine of chickens, turkeys, ducks, geese and

bustards. Disease? Babesia shortii: causes anemia in Kestrels Others: trypanosomes, aegyptianella, etc. Others: i. Rhinosporidiosis (Protista – Mesomycetozoea. Parasites of fish and amphibians) Due to R. seeberi in swans and ducks Granulomatous conjunctivitis and cutaneous lesions j. Blastocystis (Chromista/Protista)

Commonly found in the intestine (ceca) of chickens, turkeys, geese, ducks, pheasants, partridges, peafowl, ostriches, etc. Vary in size from 3 to 200 um and exist in various forms (vacuolar, granular, cystic, etc.) Significance in causing disease is unknown. Blastocystis hominis has been associated with gastrointestinal disease in humans.

Nematodes a. ASCARIASIS Common intestinal parasitism of many birds

– Chickens, turkeys, pigeons, partridges, raptors, psittacines (Australian parakeets), passerines, etc.

Etiology: Ascaridia galli (chicken), A. dissimilis (turkey), A. columbae, A. hermaphrodita, species of Porrocaecum and Contracaecum, etc.

Lesions: loss of weight, intussusception, mild enteritis if in large numbers – Eosinophilic enteritis in turkeys – Granulomas and or necrosis in livers due to larval migration in turkeys, psittacines, etc. – Bile duct hyperplasia and pericholangitis associated with larvae in bile ducts in parakeets

CAPILLARIASIS

Significant disease primarily of upper digestive tract in many species of birds – Quail, pheasants, partridges, guinea fowl, turkeys, pigeons, chickens, raptors, ducks, psittacines,

etc. Etiology: C. contorta, C. annulata, etc. Lesions: hyperplastic mucosa, fibrinonecrotic esophagitis, ingluvitis, etc. C. obsignata, C. caudinflata may cause enteritis in galliformes and columbiformes

CEREBROSPINAL NEMATODIASIS

Common condition in a variety of birds Chickens, emus, ostriches, psittacines, raptors, quail, partridges, wild birds, etc. Etiology: Baylisascaris procyonis (raccoon) most common, occasionally B. columnaris (skunk) and

badger

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Lesions: non-suppurative encephalitis associated with or with out larva/e. Brain stem most commonly involved

Larvae of Chandlerella quiscali, a filarid nematode of grackle has been associated with encephalitis in emu SYNGAMUS

Common tracheal worm (gape worm) of pheasants – Others: turkeys, geese, quail, peafowl, chickens

Etiology: Syngamus trachea Lesions: granulomatous tracheitis and occasionally bronchitis Cyathostoma bronchialis can cause bronchitis and pneumonia in geese

– Also been associated with tracheitis in emus

NEMATODES OF PROVENTRICULUS AND GIZZARD Dispharynx nasuta, Cyrnea colini, Tetrameres americana, Cheilospirura hamulosa and species of

Acuaria, Synhimantis, Habronemia, Amidostomum, Hadjelia, etc. – Occur in pigeons, chickens, quail, ducks, turkeys, pheasants, psittacines, passerines, etc. – Lesions: proventriculitis and ventriculitis – Geopetitia aspiculata (Habronemia) causes severe proventriculitis in passeriformes and others

Libyostrongylus douglassii causes severe proventriculitis in ostriches Eustrongylides ignotus causes severe proventriculitis and peritonitis in fish eating birds such as

herons, egrets and mergansers. MISCELLANEOUS NEMATODES

Heterakis isolonche: granulomatous typhlitis in pheasants Trichostrongylus tenuis: enteritis in young grouse and geese Oxispirura mansoni: conjunctivitis in galliformes Thelazia sp. have been associated with conjunctivitis in psittacines Pelecitus calamiformis (filarid): tenosynovitis associated with adult nematodes in parrots Microfilariae are common in psittacines, especially cockatoos, not pathogenic Microfilariae associated with severe pneumonia in magpies Serratospiculoides amaculata, parasite of air sacs and airways in raptors. Associated with

airsacculitis, peritonitis and necrotizing myelitis in a Prairie Falcon Serratospiculum sp. nine species known in raptors, some associated with airsacculitis and

pneumonia Paronchocerca ciconarum (filarid): myocardial degeneration with adult nematodes in a Marabou

Stork Cardiofilaria - heart worm in psittacines Cestodes Common intestinal tapeworms of many species of birds

– Chickens, turkeys, ducks, geese, pigeons, psittacines, passerines, wild birds, etc. Etiology and lesions:

– Davainea proglottina (smallest); enteritis in chickens – Raillietina echinobothridia: granulomatous enteritis in chickens – Species of Raillietina, Hymenolepis, Amoebotaenia, etc. are common in psittacines and finches

Pathogenic in large numbers, obstruction, enteritis, etc.

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Trematodes Schistosomiasis: common in waterfowl

– Dendritobilharzia sp. – Medial hypertrophy of vessels in the intestinal wall – Rarely hepatitis, encephalitis, nephritis, enteritis – Encephalitis common in swans

Dicroceliidae: been associated with dilated bile ducts and severe cholangiohepatitis in cockatoos and an amazon parrot

Gigantobilharzia sp. associated with hemorrhagic ulcerative colitis and cloacitis in a nanday conure Sphaeridiotrema globulus: causes severe ulcerative hemorrhagic enteritis in swans and cygnet and

chickens (experimental) Philophthalmus gralli: associated with conjunctivitis in ostriches Collyriclum faba cause cysts in the skin of poultry, wild birds including robins Prosthogonimus sp. oviduct fluke of poultry Tanaisia bragai in collecting tubules of kidney in poultry, pigeons, etc. Cathaemasia hians in the upper esophagus of storks Athesmia heterolecithodes causes severe hepatitis in guinea fowls Arthropods MITES Most common ectoparasites of a variety of species of birds

– Chickens, canaries, finches, psittacines, pigeons, turkeys, pheasants, wild birds, etc. Etiology (see table 3): species of Dermanyssus, Ornithonyssus, Knemidocoptes, Sternostoma, etc.

Numerous other species known. Lesions

– Anemia – Hyperkeratosis, acanthosis, epidermitis, dermatitis – Blockage, granulomatous tracheitis, airsacculitis, pneumonia – Cysts in skin, poor feather growth, loss of feathers, etc.

LICE

o Most common in poultry; chicken body louse (Menacanthus stramineus) and shaft louse (Menopon gallinae). Female lice glue their eggs (nits) to host feathers but pathology is minimal.

FLEAS

o In poultry, stick tight flea also known as tropical chicken flea (Echidnophaga gallinaceae) can cause dermatitis.

TICKS

o Fowl tick, Argus persicus can cause anemia. May transmit bacterial and rickettsial diseases. Toxicosis a. Mycotoxins Generally ducklings, turkey poults and pheasants are more susceptible Aflatoxins (B1, B2, G1 and G2): B1 most toxic, liver has congestion, necrosis, fatty change,

karyomegaly, numerous mitotic figures, bile duct hyperplasia, fibrosis, etc. – Immunosuppression, myocardial, kidney degeneration, impaired blood coagulation, etc.

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– Turkey X disease due to aflatoxin B1 + cyclopiazonic acid – Model for hepatocarcinogenesis

Citrinin, Ochratoxin, Oosporein: renal tubular necrosis and visceral urate deposition – In addition vacuoles, bile duct hyperplasia, etc. in liver associated with citrinin and ochratoxin – Ochratoxin can cause glycogen storage disease in chickens – Ochratoxin is embryocidal at low levels

Trichothecenes (T2, DAS, Vomitoxin = DON): radiomimetic effect, oral, proventricular and gizzard erosions, lymphoid necrosis and depletion, hepatic necrosis, etc.

Fumonisins: poultry are relatively resistant, hepatic necrosis, biliary hyperplasia, widening of growth plates, myodegeneration, etc.

Moniliformin: Cardiomegaly in broilers, myocardial degeneration, hepatic necrosis Fusarochromanone: tibial dyschondroplasia Cyclopiazonic acid: skeletal muscle, heart, liver, GI degeneration Zearalenone: mycotoxin with estrogen activity

– Cystic oviduct with inflammation, cysts in vent, etc. Ergotism: beak and toe necrosis b. Heavy metals Lead: one of the most commonly reported toxic compounds of waterfowl and companion birds

– Lesions: anemia, hemorrhagic enteritis, myocardial degeneration, hyalinosis of cerebral vessels with hemorrhage, nephrosis, demyelination of nerves, etc.

– Acid fast intranuclear inclusions in renal tubular epithelial cells Zinc: common in companion birds, waterfowl

– Lesions: gizzard erosion, pancreatic acinar necrosis, enteritis, nephrosis Iron: seen in a variety of birds

– Lesions: hepatic necrosis, hemolysis of RBC, hemosiderosis (in Lorikeets) c. Ionophore toxicity Ionophores widely used as anticoccidials in poultry

– Toxicity most common in turkeys and chickens – Also described in quail, guinea fowl, etc.

Monensin, Lasalocid, Salinomycin, Narasin – Various compounds including antibiotics interact and influence toxicity

Lesions: degeneration of skeletal muscles (pectoral muscles not affected) and occasionally heart (in chickens). Sartorius, adductor, semimembranous, semitendinosis, intercostal muscles most commonly affected – In addition demyelination and axonal degeneration of peripheral nerves and spinal cord have

been associated with lasalocid toxicity d. Selenium, salt, calcium Selenium: hepatopathy, alopecia of the scalp and dorsal cervical midline, broken or lost digit nails,

necrosis of the tip of the beak in ducks – pulmonary congestion and edema in an ostrich chick

Salt: Low to moderate levels causes right heart hypertrophy, dilation and ascites in turkey poults and broiler chicks and occasionally encephalomalacia – Water high in salinity causes conjunctivitis, myocardial degeneration, hyperemia of brain,

hyperplasia or atrophy of salt glands, cataracts (reversible if not severe) in wild waterfowl – Cystic testes in poultry – Symmetrical encephalomalacia in young turkey poults and occasionally in chicks

Calcium: nephrosis in young poultry e. Vitamins

42

Vitamin D: common in psittacines – Soft tissue mineralization, proventriculus, heart, air sacs, etc.

Vitamin A: conjunctivitis and rickets in chickens – Hepatic degeneration, Ito-cell hyperplasia?

f. Gases; PTFE, Ammonia, CO Polytetrafluoroethylene (PTFE): Teflon coated pans when overheated release toxic gases

– Seen in companion birds, also in free flying birds – In poultry from PTFE-coated light bulbs – Pulmonary congestion and edema

Carbon monoxide: pulmonary congestion and edema, bright red colored blood Ammonia: conjunctivitis, corneal erosions and ulcers and sinusitis and tracheitis in poultry Oxygen: in budgerigars, edema and interstitial pneumonia g. Rodenticides Diphacinone, Brodifoucum, Bromodiolone: blood in abdominal cavity, hemorrhage in liver Zinc phosphide: hydropericardium, pulmonary edema, congestion and hemorrhage in liver,

congestion in kidney h. Antibiotics Gentamicin, Amikacin - nephrosis Sulfa drugs - disseminated hemorrhages, nephrosis Tetracyclines - nephrosis Furazolidone - round heart, hepatocellular vacuoles Polymyxin E-1. in ostriches, congestion of meningeal vessels, vacuolization of the plexus of

Auerbach, edema in the heart and intestinal serosa i. Plants Avocado and oleander: myocardial degeneration Oak: nephrosis Green acorns (pyrogallol): gastroenteritis, congestion and edema of organs Coffee senna: degeneration of muscles Gossypol: hepatic necrosis, biliary hyperplasia, perivascular inflammation Spring Parsley (Cymopterus watsonii), celery: photosensitization, dermatitis Blue green algae (Microcystin): Hepatic necrosis Onion: hemosiderosis in liver in White Chinese geese. Yew: no significant lesions j. Others Organophosphates - acute and delayed neurotoxicity

– Acute, inhibition of acetyl cholinesterase, no lesions – Delayed, axonal degeneration in peripheral nerves and spinal cord, adult chicken is the (test)

animal model, young birds are resistant Nitrate, Nitrite: Brown mucus membranes, methemoglobinuria Arsenilic acid, nitro-phenyl-arsenic acid: demyelination of peripheral nerves Sodium Sesquicarbonate: nephrosis, visceral gout, fluid in intestine Quaternary Ammonium: erosions and ulcers in upper GI tract Domoic acid (marine neurotoxin):

– In pelicans and cormorants – Hemorrhage and necrosis in skeletal muscles

Diclofenac (NSAID) – caused high mortality (due to 2O poisoning) in vultures in the Indian subcontinent. Nephrosis and visceral urate deposits

Avian vacuolar myelinopathy

43

– Cause: toxicity due to Cyanotoxins (metabolites of cyanobacteria – blue green algae) is suspected

– In bald eagles, coots, geese, owls and others – Spongy degeneration of the white matter of CNS but most prominent in optic lobes and swollen

axons in spinal cord. Optic nerve also affected. Metabolic diseases a. Goiter In male mature buff Cochin chickens (Dr. D. Webb, IL) Severely enlarged cystic thyroid glands with follicles lined by flattened epithelial cells Genetics suspected b. Hemochromatosis Abnormal accumulation of iron in tissues associated with tissue disturbance such as cirrhosis Most common in mynahs, toucans, crows, starlings, ducks, fruit doves, horn bills, psittacines

(Lorikeets), etc. Hepatic degeneration, fibrosis, myocardial degeneration, ascites, etc. Genetics, nutrition (iron), hemorrhagic syndromes, starvation, etc. c. Diabetes mellitus Poorly understood It has been described in psittacines, toco toucans and a red-tailed hawk Glucagon is the major glucose - regulating hormone in granivorous birds Carnivorous birds are similar to mammals Lesions

– Hyperplasia of islet cells Decrease in insulin secreting cells (by IHC)

– Enlarged islets with eosinophilic cytoplasm in toco toucans – Islet cell tumor

d. Amyloidosis Most common in ducks and finches Also in other water fowl, game birds, turkeys, chickens, psittacines, ratites, canaries, flamingos,

touracos, pigeons, doves, etc. Can be associated with chronic infections Genetics probably plays a major role in its occurrence in commercial ducks, as young as 3-4 week-

old ducklings may have severe amyloidosis in the spleen with out apparent co-infections. Accumulation of amorphous eosinophilic material in various tissues Liver, spleen, intestine, adrenal, kidney, synovium, heart, pancreas, thyroid, skin, brain, lung,

proventriculus, etc. Lesions

– Gross: ascites (water belly) in commercial ducks, firm enlarged and waxy liver sometimes with nodules, enlarged mottled white spleen, pale or brownish kidneys, etc.

– Microscopic: interstitial accumulation of amyloid in liver with hepatocellular atrophy in severe cases, kidney, adrenal, thyroid, pancreas, spleen, in the lamina propria of intestine and proventriculus, in subepithelium of synovium, bronchus, in myocardium, brain, skin, vessels, etc. Severe hepatic capsular fibrosis and nodules made up of hyperplastic hepatocytes

Amyloid arthropathy in Brown Leghorn chickens o Cause: Enterococcus faecalis, Mycoplasma synoviae, M. gallisepticum, S. aurues and others o Lesions: Orange colored exudate in the synovium

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o Amyloid associated with Hepatitis-splenomegaly syndrome in mature broiler and laying-type chickens

o Cause: Hepatitis E virus o Lesions: enlarged mottled pale spleen and enlarged and hemorrhagic liver. Amyloid

primarily in the spleen e. Gout (visceral and articular urate deposits) Uric acid is the end product of protein and purine metabolism (uricotelic) in birds, where as in

mammals’ urea is the end product (ureotelic) Birds lack the enzyme carbamyl phosphate synthetase to dispose of ammonia and the enzyme

uricase to decarboxylate uric acid to allantoin Gout is a metabolic condition where abnormal accumulation of white chalky or white semifluid-like

urates in soft tissues of various organs in the body Gout occurs as two distinct syndromes, visceral and articular gout urate deposits

– The term “gout” has been replaced with the term “urate deposits” These two syndromes differ in age of onset, frequency, sex predilection, gross and microscopic

lesions, pathogenesis and causes Great deal of confusion exists between the two syndromes because urate deposition takes place in

joints in visceral urate deposits (gout) also See table 4 to help clarify differences between the two syndromes f. Hepatic Lipidosis Common in some psittacines; budgerigars, amazons, rose breasted cockatoos, shell parakeets,

lorikeets, etc. Diet, environment, toxicities, hormones, genetics (shell parakeets) influence lipidosis Lesions: obesity, hepatic lipidosis, and lipidosis in liver and other organs in shell parakeets g. Hemorrhagic fatty liver syndrome (chickens) Condition of obese layer-type chickens Fat in abdominal cavity, fatty livers, hemorrhagic or ruptured livers h. Atherosclerosis Very common in psittacines especially in amazons and African Greys Others: ducks, geese, chickens, turkeys, ostriches, flamingoes, herons, vultures, falcons, pigeons,

etc. Etiology: diet, environment, genetics, virus, age, etc.

– Marek’s disease virus (herpesvirus) can induce atherosclerosis in chickens – White Carneaux pigeon used as model

Lesions – Thickened walls or plaques in brachiocephalic, carotid, abdominal aorta, etc., coronary arteries

and other arteries are rarely involved, myocardial degeneration and fibrosis – Thickening of intima and media with lipid laden cells

i. Mucopolysaccharidosis type IIIB (emu) Also called Sanfilippo B syndrome First description in any animal

Deficiency of N-acetyl--D-glucosaminidase Probably inherited as a autosomal recessive trait Signs and lesions

– Sudden death, neurological signs – Ruptured liver or subcutaneous hemorrhages – Accumulation of membrane bound substance in neurons of nervous tissue and visceral organs

j. Storage disease in Costa’s Hummingbirds

45

Neurologic signs; flying backwards, swaying, head tilt, flying in circles, head tremors Vacuoles in swollen neurons, cells of bone marrow, spleen, gland of Harder, uropygeal gland and

inner nuclear layer of retina k. Inherited Muscular dystrophy in chicken Seen in New Hampshire breed and similar dystrophy-like myopathy has been described in Cornish

breed Clin. signs: unable to elevate wings beyond horizontal plane and unable to right themselves when

placed on their backs Lesions: grossly enlargement of pectoral muscles initially and later atrophy, microscopically variation

in fiber size, increased nuclei, vacuoles, necrosis, fragmentation and replacement by adipose tissue l. Myotonic dystrophy in mutant (LWC strain) Japanese Quails As early as 28 days of age generalized myotonia, muscle stiffness, muscle weakness Lesions: ring fibers, sarcoplasmic masses, internal migration of sarcolemmal nuclei, variation in fiber

size, replacement by fat cells and lenticular cataracts m. Type II Glycogen storage disease in Japanese Quail Acid maltase deficiency n. Aortic aneurysm/rupture Most common in male turkeys but also seen in ostriches and emus

– Most common in the abdominal aorta at the origin of the celiac artery – Longitudinal slit in the posterior abdominal aorta or rarely at the origin of aorta – Medial degeneration and loss of elastic fibers, subintimal thickening, displacement of elastic

lamina, increased amount of collagen, necrosis, rupture – Genetics, hypertension, low copper, vasa vasorum defect? – Aortic rupture in psittacines due to invasion of Aspergillus sp.

Coronary artery aneurysm (turkeys) – In male turkeys, 15 -16 weeks-old, 1.5-3.5% mortality – Hemopericardium, hemorrhage across base of heart, subintimal thickening, medial

degeneration of coronary artery, rupture – Genetics, hypertension, low copper, increased body weights?

o. Round heart disease (turkeys) Also called spontaneous cardiomyopathy Common condition in young commercial turkeys Dilated ventricles, chronic passive congestion of liver

– Cause has been determined to be due to genetics – Been used as a model to study cardiomyopathy

p. Ascites syndrome (chickens) Common condition in broiler chickens Right heart hypertrophy later dilation, passive congestion of liver and ascites. Pulmonary congestion

and edema Rapid growth coupled with insufficient pulmonary capillary capacity aggravates pulmonary

hypertension leading to right heart failure q. Tibial dyschondroplasia (TD) Common condition in broiler chickens and turkeys and ducks Abnormal masses of cartilage below the growth plate primarily in the proximal tibiotarsus but

occurs also in the tarsometatarsus – Presence of prehypertrophic cartilage with no vascular channels – Etiology: multifactorial, nutrition, genetics, mycotoxin, etc.

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Similar picture as TD can be seen grossly in the long bones of ratites but it is not TD nor it is pathologic – In ratites it is normal embryonic cartilage which gets resorbed by 6-8 weeks of age

r. Deep pectoral myopathy Seen in well muscled broilers and turkeys Green discoloration of primarily supracoracoideus muscle due to ischemic necrosis s. Perirenal hemorrhage Seen in rapidly growing turkeys, 8-14 weeks of age Hemorrhage over portion or entire kidney Underlying vascular problems? Probably due to small ruptures or tears in the posterior abdominal

aorta and its branches? t. Xanthomatosis Common in psittacines and occasionally in chickens Yellow subcutaneous swelling or nodules in the body cavity Giant cells, lymphocytes, macrophages with cholesterol clefts Very common in the bone marrow of many species of birds u. Auto immune thyroiditis (chicken) Occurs spontaneously in obese strain of chicken Used as model to study Hashimoto’s thyroiditis Birds have long and silky feathers, large amount of abdominal fat Thyroids become small gradually as the bird matures and atrophies Lymphocytic infiltration with few macrophages and lymphoid nodules, loss of architecture, thyroid

gland Antibodies to thyroglobulin Hyperlipidemia, low T3 and T4 and IgA deficiency Been described in Fayoumi breed of chickens with feather amelanosis Diseases of Malnutrition a. Xerophthalmia In non-commercial poultry, psittacines, etc. Etiology: vitamin A deficiency Lesions: pustule-like nodules in upper GI tract, exudate in conjunctiva, nasal cavity, nephrosis,

opaque dry cornea, hyperkeratosis of plantar surfaces – Microscopic lesions: squamous metaplasia of epithelium and hyperkeratosis in esophagus,

conjunctiva, salivary and salt glands, respiratory tract (sinus/turbinates, larynx, trachea, syrinx, bronchus/parabronchus), bursa of Fabricius, proventriculus, ureter, feather follicles, etc.

b. Polyneuritis Rarely seen in poultry Etiology: vitamin B1 (thiamin) deficiency Lesions: prominent peripheral nerves with edema and infiltration of mononuclear cells Malacia of the brain in fish eating birds c. Rickets/osteomalacia Rickets in younger birds and osteomalacia in older birds

– In poultry, ratites, psittacines, zoo birds, etc. – Etiology: deficiency of calcium, phosphorus and vitamin D3 or an imbalance in calcium to

phosphorus ration (normal 2:1)

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– Lesions: soft and pliable beak, claws and keel, beading of ribs (‘rickety rosary’), enlarged epiphysis, fractures of long bones, enlarged parathyroid glands Microscopic:

Calcium deficiency - lengthened Proliferating Prehypertrophied Zone and short Degenerating Hypertrophied Zone (DHZ), hyperplasia of parathyroid glands

Phosphorus deficiency/calcium excess: lengthened DHZ Vitamin D3 deficiency - similar to calcium deficiency

d. Encephalomalacia In young chickens, turkeys, pheasants, geese, ducks, etc.

– Can also be seen in older birds Etiology: vitamin E deficiency. (Note: not associated with Selenium deficiency) Lesions: soft and enlarged cerebellum, petechiae, hemorrhages especially in turkey poults

– Microscopic: malacia, hemorrhage, vascular thrombosis, demyelination in brain – Occasionally spinal cord involved, poliomyelomalacia

Yellow fat disease in wild birds: herons, etc. – Fat is brownish yellow, steatitis

e. Muscular dystrophy/exudative diathesis In chickens, quail, turkeys, pelicans, ducks, etc. Etiology: vitamin E/Selenium deficiency Lesions

– Subcutaneous green-tinged fluid – Pale streaks in skeletal muscles, gizzard and heart (ducks and pelican)

Degeneration of skeletal muscle, heart, gizzard, pancreatic acinar necrosis f. Curled-toe paralysis Seen in chicks, turkey poults, ducklings Etiology: vitamin B2 (riboflavin deficiency) Lesions: swelling of peripheral nerves, axon and myelin degeneration, Schwann cell proliferation,

mononuclear cell infiltration, etc. g. Pyridoxine (B6) deficiency Perosis, neurological signs in chicks and ducks and reduced egg production and hatchability in laying

chickens and turkeys Microcytic hypochromic anemia in ducks h. Perosis/slipped tendon (chicks, poults) Etiology: manganese and choline deficiency Lesions: deformity of hocks, enlargement of condyle, bowing of tarsometatarsus, slipping of

gastrocnemius tendon – Deficiency of pantothenic acid, biotin, folic acid, niacin can cause similar lesions – In addition dermatitis can be seen in birds deficient in biotin and pantothenic acid and poor

feathering and anemia in niacin deficiency i. Goiter Common in psittacines especially in budgerigars Also seen in pheasants, geese, chickens, etc. Etiology: Iodine deficiency Lesions: enlarged thyroid glands, some times cystic Micro: severe hyperplasia of follicle epithelium with papillary projections, pale or lack of colloid,

hemorrhage and severe effacement of the gland in extreme cases

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Neoplasia Most common in chickens and psittacines especially budgerigars among birds

– Historic significance; retroviruses and chickens have served as models to study various phenomenon of neoplasia

In chickens most are caused by viruses such as retroviruses (see Leucosis/Sarcoma group, Reticuloendotheliosis group) and herpesvirus (Marek’s Disease)

Tumors of unknown etiology in chickens include Squamous cell carcinoma (Keratoaconthoma) of the skin, ovarian/oviductal Adenocarcinoma (carcinomatosis), leiomyoma of the mesosalpinx, teratoma of testes, multicentric histiocytosis, etc. – Squamous cell carcinoma (keratoacanthoma) of skin occur as small nodular or ulcerative lesions

in broiler chickens leading to condemnations, no evidence of metastasis – Ovarian carcinoma in hens used as model to study ovarian cancer in women. Ovarian

carcinomas appear as multiple to numerous pale nodules in the coelomic cavity and on the serosa of the intestine with adhesions between loops of intestine and ovary and oviduct. Ascites common

– Leiomyoma of mesosalpinx – very common in hens and appears as a small to large (2x2 cm) pale nodule in the mesosalpinx and occasionally as small nodules in the coelomic cavity and abdominal viscera

Birds in the order Passeriformes have the lowest incidence – Lymphoma in canaries and finches are common – Cutaneous papilloma associated with papillomavirus associated in chaffinch and brambling

finches Incidence in budgerigars range from 16 to 24 % Etiology of tumors is not known in psittacines and other species of birds Some of the mammalian markers (IHC) to identify tumors do work in birds Some of the common tumors in psittacines include renal tumors, fibrosarcoma, squamous cell

carcinoma, lymphoma, papillomas, tumors of the gonads (testes, ovary, and oviduct), gastric carcinoma, osteoma, osteosarcoma, leiomyosarcoma, rhabdomyoma/sarcoma, pituitary adenoma, air sac, etc. – Integument: lipoma/sarcoma, myelolipoma, hemagioma/sarcoma, squamous cell carcinoma,

fibroma/sarcoma, lymphoma, basal cell tumors, mast cell tumors, melanoma, granular cell tumor, uropygial gland tumors, folliculoma, etc.

– GI tract: gastric carcinoma, papillomas, bile duct carcinoma, etc. Gastric carcinoma most commonly arising from proventriculus. Tumors extend in to the

submucosal and muscular layers. Desmoplastic reaction common Papilloma’s are most common in cloaca but can involve tongue, pharynx, esophagus, and

crop. Often birds have bile duct and occasionally pancreatic duct tumors in birds with cloacal papillomas. Herpesvirus sequences have been associated with cloacal papillomas but does not prove cause and effect relationship. Papillomavirus has been demonstrated in the cutaneous papilloma in an African Gray parrot

– Urinary tract: renal tumors are most common in psittacines and have been extensively studied to demonstrate virus but none so far. Various forms; adenoma, cystadenoma, Adenocarcinoma, nephroblastoma, etc., have been

described. Size can vary but some impinge on sciatic nerve causing paresis. Some can compromise renal function.

– Hemopoetic tumors: multicentric lymphosarcoma is most common involving liver, spleen, kidneys, bone marrow, skin, thymus, pancreas, etc. The tumors can be diffuse or nodular.

49

– Pituitary adenoma: one study described a high incidence but the cases were solicited. Chromophobe adenomas are most common often presented with exophthalmus and/or neurological signs. Carcinoma’s with metastasis can occur

References: 1. Barnes, J. E. Avian Pathology, Class notes. College of Veterinary Medicine, North Carolina State

University, Raleigh, NC. 2. Lowenstine, L. J and others. Comparative Avian Anatomy and Pathology, Class notes. School of

Veterinary Medicine, University of California, Davis, CA. 3. Avian Histopathology, 2008, Ed. O. Fletcher, 3rd Ed, AAAP publication. Jacksonville, FL. 4. Color Atlas of Avian Histopathology, 1996, C.J. Randall and R.L. Reece, Mosby-Wolfe 5. Diseases of Poultry, 2008, Ed. Y. M. Saif, et al., Blackwell Publishing, Ames, Iowa 6. Color Atlas of Diseases and Disorders of the Domestic Fowl, 1991, C.J. Randall, Iowa State University

Press, Ames, Iowa 7. Avian Medicine: Principles and application, 1994, Ed. B. W. Ritchie, G.J. Harrison and L.R.Harrison,

Wingers publishing, Lakeworth, FL 8. Pathology of Zoo Animals, 1983, L. A. Griner, Zoological society of San Diego, CA 9. The comparative Pathology of Zoo Animals, 1980, Ed. R. J. Montali and G. Migaki, Smithsonian

Institution Press, Washington, DC. 10. Field manual of Wildlife Diseases: General Field procedures and diseases of migratory birds, 2001,

Ed. M. Friend, US dept. Interior, Fish and Wildlife Service pub, Washington, DC. 11. Diseases of Cage and Aviary birds, 1996, W. J. Rosskopf and R.W. Woerpel, Williams and Wilkins, PA 12. Diseases of Wild waterfowl, 1981, G.A. Wobeser, Plenum Press, NY 13. Pathology of Pet and Aviary Birds, 2003. R. E. Schmidt, D. R. Reavill and D. N. Phalen. Blackwell

Publishing, Oxford, UK. Journals: Avian Pathology, Avian Diseases, Veterinary Pathology, J Comparative Pathology, Veterinary Record, JAVMA, AJVR, JAMS, Poultry Sci., etc. Anatomy and Physiology:

1. Anatomy of the Domestic Birds by R. Nickel et al., Verlag Paul Parey, 1977. 2. Form and Function in Birds. Ed by A. S. King and J. McLelland. 3 Volumes, Academic

Press, 1979. 3. A color Atlas of Avian Anatomy by J. McLelland. W. B. Saunders Co., 1979.

4. Sturkie’s Avian Physiology. Ed by G. C. Whittow. Academic Press, 2000.

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Table 1: Oncogenes originally identified through their presence in transforming retroviruses

Oncogene

Protein

Source of virus

Tumour

abl Kinase Mouse, cat Pre-B-cell leukaemia

akt Kinase Mouse T-cell lymphoma

crk Kinase activator Chicken Sarcoma

erb-A TH-R Chicken Erythroleukaemia

erb-B EGF-R Chicken Erythroleukaemia

ets TF Chicken Myeloid leukaemia

fes/fps Kinase Chicken/cat Sarcoma

fgr Kinase Cat Sarcoma

fms Kinase Cat Sarcoma

fos TF Mouse Osteosarcoma

jun TF Chicken Fibrosarcoma

kit Kinase Cat Sarcoma

mil/raf Kinase Chicken/mouse Sarcoma

mos Kinase Mouse Sarcoma

myb TF Chicken Myeloid leukaemia

myc TF Chicken Myelocytoma, lymphoma, carcinoma

H-ras G-protein Rat Sarcoma

K-ras G-protein Rat Sarcoma

rel TF Turkey Reticuloendotheliosis

ros Kinase Chicken Sarcoma

sea Kinase Chicken Sarcoma, leukaemia

sis PDGF Monkey Sarcoma

ski TF Chicken Carcinoma

src Kinase Chicken Sarcoma

yes Kinase Chicken Sarcoma

Abbreviations: EGF-R, epidermal growth factor; PDGF, platelet-derived growth factor; TH-R, thyroid hormone receptor; TF, nuclear transcription factor. Chicken genes are shown in bold. Ref: R. A. Weiss. The oncologist’s debt to the chicken. Avian Path. 27:S8-S15, 1998.

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Table 2. Relative frequency of microscopic lesions in various organs of psittaciformes diagnosed of having PDD

Organ

# Examined

# With Lesions

%

Prov/Gizzard

112

112

100

Adrenal

56

50

89.3

Intestine

89

77

86.5

Heart

87

69

79.3

Brain/spinal cord

66

52

78.8

Esophagus/crop

61

44

72.1

Peripheral nerves

28

20

71.4

Eye

12

8

66.7

Skin

24

6

25.0

Pancreas

64

11

17.2

Thyroid

31

3

9.6

Liver/lung/spleen/kidney

102

0*

0.0

* Incidental findings not included. Ref: Shivaprasad et al., Pathology of Proventricular Dilation Syndrome, Vet Path 34:500, 1997.

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Table 3. Mites in Birds

Name Common Name Species of birds affected

Dermanyssus gallinae* Red mite (Roost mite, Poultry

mite) Chickens, turkeys, pigeons, canaries,

wild birds

Ornithonyssus sylviarum* Northern Fowl mite Chicken, turkeys, wild birds

O. bursa Tropical Fowl mite Poultry, pigeons, Mynah

Knemidocoptes mutans* Scaly-leg and scaly-face mites Poultry

K. pilae* Scaly-leg and scaly-face mites Psittacines

Procnemidokoptes janssensi Scaly-leg and scaly-face mites Love birds

K. jamaicensis Scaly leg mite Canaries, finches, other passerines

Knemidocoptes gallinae Depluming mite Chickens, pigeons, pheasants

K. laevis Depluming mite Pigeons

Neocnemidocoptes gallinae Depluming mite Pheasants and others Epidermoptes bilobatus Skin mite Chickens Myialges nudus Skin mite Grey-cheeked parakeets Harpyrynchus sp. Skin and feathers Passerines Syringophilus hipectinatus Feather and quill mites Poultry, wild birds

S. columbae Feather and quill mites Pigeons

(Dermoglyphus sp., Analges sp., Mengninia sp., Freyana sp)

Feather and quill mites Chickens, turkeys

Paraglopsis sp. Feather and quill mites Psittacines, finches Sternostoma tracheacolum*

(Neonyssus, Rhinonyssus) Respiratory tract mite (trachea,

lung, air sac) Passerines (canaries, finches),

psittacines, poultry, pigeon

Cytodites nudus Air sac mite (bronchi, lungs, air

sac) Poultry, pheasants, pigeons, canaries,

etc.

Laminosioptes cysticola Cyst mite (skin, subcutis, muscle,

abdominal viscera and lungs) Chicken, turkeys, pigeons, pheasants

geese Hypopial mites Areolar subcutaneous,

connective tissue Pigeons

Family Trombiculidae (Neoschonagastia americana)

Chiggers Poultry (Southern US), turkeys, wild birds, chickens, pigeons, psittacines

* Most common

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Table 4: Differences between Visceral urate deposition and articular urate deposition in Birds

Visceral urate deposition (Visceral gout)

Articular urate deposition (Articular gout)

1. Onset:

It is usually an acute condition but can be chronic.

It is usually a chronic disease.

2. Frequency:

It is very common.

It is rare or sporadic.

3. Age:

1 day and above.

4-5 months and above. However, immature genetically susceptible chickens may be induced by high protein levels in the diet.

4. Sex:

Both males and females are susceptible.

Mostly males.

5. Gross lesions

Kidney:

Kidneys are almost always involved and they look grossly abnormal with deposition of white, chalky precipitates.

Kidneys are normal grossly. Kidneys may become abnormal with white urate deposits if the bird gets dehydrated.

Soft tissues:

Visceral organs like liver, myocardium, spleen or serosal surfaces like pleura, pericardium, air sacs, mesentery, etc. are commonly involved.

Soft tissues other than synovium are rarely involved, however, comb, wattles, and trachea have been observed to be involved.

Joints:

Soft tissues around the joints may or may not be involved. Surfaces of muscles, synovial sheaths of tendons and joints are involved in severe cases.

Soft tissues around the joints are always involved, especially feet. Other joints of the legs, wing, spine, and mandible are also commonly involved.

6.Microscopic

lesions:

Generally no inflammatory reaction in synovium or visceral surfaces. Kidney has inflammatory reaction around tophus.

Granulomatous inflammation in synovium and other tissues.

7. Pathogenesis:

It is generally due to failure of urate excretion (renal failure).

It is probably due to a metabolic defect in the secretion of urates by the kidney tubules.

8. Causes:

1. Dehydration. 2. Nephrotoxicity: calcium, mycotoxins, (ochratoxins, oosporein, aflatoxins, etc.), certain antibiotics, heavy metals (lead), ethylene glycol, ethoxyquin etc. 3. Infectious agents: nephrotropic IBV and avian nephritis virus (chickens), polyomavirus, PMV-1 (pigeons), Salmonella sp., Yersinia sp., Chlamydia psittaci, Eimeria truncata, microsporidia, cryptosporidia, Aspergillus sp., etc. 4. Vitamin A deficiency 5. Urolithiasis 6. Neoplasia (lymphoma, primary renal

a. Genetics. b. High protein in the diet. c. Others?

54

tumors) 8. Immune mediated glomerulonephritis 9. Anomalies 10. Others?

Ref: Shivaprasad, H. L. An overview of anatomy, physiology and pathology of urinary system in birds, AAV Proceedings, pp. 201-205, 1998

55

Diseases or etiologies of the Cardiovascular System in Poultry - An Outline

Anomalies:

1. ASD, VSD 2. Dextraposition of major vessels. 3. Subpulmonic and subaortic stenosis 4. Ventricular hypoplasia 5. Others:

Metabolic:

1. Ascites syndrome (chickens) 2. Round heart disease (dilated cardiomyopathy in turkeys) 3. Aortic (and coronary) ruptures (turkeys) 4. Amylodosis. 5. Urate deposition 6. Atherosclerosis 7. Others:

Virus and viral diseases:

1. Marek’s disease (lymphoid tumors) 2. Retroviruses (LL; inclusion bodies, REV, Myelocytoma) 3. Goose herpesvirus (myocarditis) 4. Avian Paramyxovirus -1 (END) 5. Orthomyxovirus (HPAI) 6. Goose parvovirus (myocarditis with IN inclusions) 7. Muscovy duck parvovirus 8. Reovirus (myocarditis in turkeys and chickens) 9. Avian Encephalomyelitis virus (Picornavirus) 10. Flavivirus (WNV in ducks and geese) 11. Alphaviruses (WEE, EEE, Highland J) 12. Adenovirus group I, serotype 4 (Angara disease) 13. Duck Viral Enteritis (herpesvirus). 14. Others: Bunyavirus (ostrich)

Bacteria and bacterial diseases:

1. Salmonellosis (S.pullorum/S.gallinarum, S. typhimurium, S. enteritidis, etc.) 2. Colibacillosis 3. Staphylococcosis 4. Listeriosis 5. Pasteurellosis (P. multocida, P. gallinarum) 6. Riemerella anatipestifer 7. Ornithobacterium rhinotracheale 8. Mycoplasmosis 9. Chlamydiosis 10. Erysipelothrix rhusiopathiae 11. Mycobacteriosis 12. Streptococcosis 13. Enterocccus sp.

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Mycosis:

1. Aspergillosis 2. Zygomyces 3. Candida sp.

Parasites: 1. Toxoplasmosis 2. Leucocytozoonosis 3. Sarcocystosis 4. Hemoprotozoa 5. Schistosoma of billharzia sp. (medial hypertrophy of vessels in waterfowl)

Nutritional: 1. Biotin def (Fatty liver and kidney syndrome, fatty change in myocardium) 2. Vitamin E/Selenium 3. Copper def ? (aorta/coronary artery rupture) 4. Others

Neoplasia:

1. Virus induced neoplasia 2. Rhabdomyoma/sarcoma 3. Hemangioma/sarcoma 4. Fibrosarcoma 5. Metastatic adenocarcinoma (rare) 6. Others

Toxicity:

1. Ionophores 2. Sodium (hydropericardium, ascites) 3. Furazolidone 4. Lathyrism – aortic rupture (BAPN β-aminoproprionitrile) 5. Moniliformin 6. Plants (Cassia, Avacado, Oleander, etc.) 7. Heavy metals (lead) 8. Toxic fat syndrome (dioxins, PCB’s) 9. Others

Others:

1. Anomalies 2. Amyloidosis 3. Visceral urate deposition 4. Valvular insufficiency 5. Endocardiosis 6. Cardiomyopathy/Round heart disease of chickens and turkeys. 7. Atherosclerosis 8. Aortic/coronary artery rupture 9. Perirenal hemorrhage 10. Hemopericardium/myocardial rupture 11. Others:

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Diseases of the Digestive System including Liver and Pancreas - An Outline

Viruses and Viral Diseases:

1. Pox 2. Marek’s disease (lymphoid tumors) 3. Avian Paramyxovirus -1 (END) 4. Orthomyxovirus (HPAI) 5. Herpesvirus of ducks (DVE) 6. Adenovirus type II of turkeys (HEV) 7. Coronavirus (turkeys) 8. Rotavirus (groups A and D – poult enteritis) 9. Astrovirus (poult enteritis) 10. Enterovirus (poult enteritis) 11. Reovirus (malabsorption syndrome) 12. EEE (Ratites, turkeys experimental) 13. Polyomavirus (Goose haemorrhagic nephritis – Europe) 14. Novel Birnavirus (Transmissible proventriculitis) 15. Adenovirus type I (IBH) 16. Novel Picornavirus (Turkey Viral Hepatitis) 17. Hepatitis E virus (Hepatitis Splenomegaly Syndrome) 18. Retroviruses (LL, REV, Myelocytomatosis, etc.) 19. Duck Hepatitis I (Picornavirus) 20. Duck Hepatitis II (Astrovirus) 21. Hepadnavirus (Ducks) 22. Avian Encephalomyelitis virus (Pancreas) 23. Parvovirus (infectious bill atrophy in ducklings)

Bacteria and Bacterial Diseases:

1. Salmonellosis (S. pullorum/S. gallinarum, S. typhimurium, S. arizonae, etc.) 2. E. coli (AEEC, Coligranuloma) 3. C. perfringens 4. C. colinum 5. C. sordellii 6. Mycobacteriosis (M. avium) 7. P. multocida (ducks) 8. Erysipelothrix rhusiopathiae 9. Brachispira pilosocoli 10. C. difficile (ostrich) 11. Lawsonia intracellularis (emu) 12. Yersinia pseudotuberculosis 13. Listeriosis 14. Chlamydiosis 15. Mycoplasmosis (MG, MS) 16. Staphylococcosis 17. Streptococcosis 18. Vibrionic hepatitis 19. Eubacterium tortuosum 19. Others

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Mycotic Diseases: 1. Candida sp. 2. Zygomyces 3. Megabacteria (Macrorhabdus ornithogaster, ascomycetous yeast)

Parasitic Diseases: Protozoa

1. Coccidiosis (Eimeria sp.) 2. Cryptosporidia sp. 3. Histomonas meleagridis (Blackhead) 4. Cochlosoma anatis 5. Hexamitiasis 6. Trichomoniasis 7. Amebiasis 8. Toxoplasmosis

Nematodes 1. Capillaria annulata, C. contorta 2. Capillaria caudinflata, C. obsignata 3. Tetrameres americana (proventriculus) 4. Dispharynx nasuta (proventriculus) 5. Amidostomum sp. (gizzard) 6. Cheilospirura hamulosa (gizzard) 7. Ascaridia galli 8. Ascaridia dissimilis (turkeys) 9. Heterakis gallinarum 10. H. isolonche 11. Trichostrongylus tenuis

Cestodes and Trematodes 1. Davainea proglottina 2. Raillietina tetragona 3. R. echinobothridia (nodules in intestine) 4. Amphimerus elongatus (fluke in liver, pancreas and bile ducts of ducks and turkeys) 5. Schistosoma sp. Many species of billharzia (medial hypertrophy of vessels in the intestine of waterfowl)

Nutrition:

1. Vitamin A deficiency (squamous metaplasia) 2. Fine feed (oral ulcers) 3. Vitamin E (gizzard myopathy) 4. Selenium (pancreatic fibrosis) 5. Biotin (Hepatic and renal lipidosis) 6. Methionine ?(Hepatic lipidosis in turkeys) 7. Hemorrhagic fatty liver syndrome (nutrition?) 8. Manganese (Short beak) 9. Niacin (black tongue)

Neoplasia: 1. Lymphoma of virus induced (Marek’s, LL, REV, etc.) 2. Squamous cell carcinoma 3. Salivary gland adenocarcinoma 4. Proventricular adenocarcinoma 5. Myxosarcoma (gizzard) 6. Intestinal adenocarcinoma 7. Bilary carcinoma

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8. Metastatic adenocarcinoma (ovary/oviduct) 9. Hemangiosarcoma 10. Others

Toxicity:

1. Quaternary ammonium 2. Copper and copper sulfate 3. Trichothecene mycotoxins (T2) 4. Dicalcium phosphate 5. Photosensitization 6. Cantharidin (blister beetle consumption in Emu’s). 7. Hypersalinity (ducks on hypersaline lakes) 8. Arsenic, organic 9. Lead (dilation of crop/proventriculus due to vagus degeneration, gizzard erosions) 10. Zinc (gizzard erosions) 11. Biogenic amines (gizzerosine – gizzard erosions) 12. Vitamin D (soft tissue mineralization - proventriculus) 13. Selenium (beak deformity) 14. Phenol and chlorinated hydrocarbons (including PCB’s and PBB’s) 15. Aflatoxins 16. Fumonisin 17. Rodenticides (Diphacinone, zinc phosphide) 18. Ethoxyquin (phorphyrin in liver) 19. Others

Others:

1. Amyloidosis 2. Visceral urate deposition (gout) 3. Iron storage disease 4. Protophorphyrin accumulation 5. Hepatic fibrosis (ascites syndrome, right heart failure, constrictive pericarditis) 6. Mucopolysacchridosis type IIIB (Emu) 7. Traumatic ventriculitis (foreign body) 8. Cloacal/intestinal prolapse (Cannibalism, rodents) 9. Crop/esophagus impaction 10. Improper beak trimming (neuroma) 11. Pendulous crop 12. Anomalies 13. Others

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Histopathologic Diagnoses of the Diseases of the Respiratory System in Poultry

Diseases affecting the respiratory and digestive systems in poultry are some of the most common diseases seen in the farms. These two systems may account for nearly 70 % of all the cases seen in a diagnostic laboratory or in the poultry farms. Disease of the respiratory system in general is not only one of the most complex but also one of the most economically important problems in the field where chickens and turkeys are raised indoors and intensively. This outline will cover the common viral, bacterial, fungal, parasitic, nutritional, toxic and miscellaneous diseases affecting the respiratory system of chickens and their diagnoses by histopathology. However, in the field it is very rare that chickens or turkeys are confronted with one single etiology such as a virus or bacteria or parasite or fungi, etc., but a combination of various disease agents. The diseases of the respiratory system are also greatly influenced by the environment they are in as well as various management factors including vaccinations Chilling and overheating also influence respiratory diseases. Regardless of whatever management practices are used, genetics and nutrition play a significant role in the initiation and outcome of a disease.

Briefly the anatomy of the respiratory system in poultry consists of external nares, nasal passages (turbinates and sinuses), choana (palatine cleft), larynx, syrinx, bronchi (primary,), lungs which are covered by pleura and contains secondary and tertiary or parabronchi (with atria and air capillaries) and air sacs. Other organs that are either directly or indirectly connected with the respiratory system include pharynx leading to the eustachian tubes and middle ears, conjunctiva including membrana nictitans (3rd eyelid), gland of Harder, lacrimal gland and nasal or salt gland. Most of these organs are lined by cuboidal or ciliated columnar epithelium and contain lamina propria and goblet cells. Gland of Harder located behind the eye and is an important gland that contain plasma cells that secrete antibody (IgA) which along with the mucocilliary system in the nasal cavity, trachea and bronchi provides a major defense mechanism to the respiratory system.

Clinical signs due to respiratory disease range from nasal and ocular discharge, gasping or open mouth breathing, wheezing, snick with various mortalities in a flock can be observed. Rarely the birds may not have any clinical signs and die acutely such as in Bird flu and Newcastle disease. Similarly gross and microscopic lesions due to respiratory diseases range from fibrinous to lymphoplasmacytic airsacculitis, pleuritis, pneumonia, sinusitis/rhinitis, laryngitis, tracheitis and conjunctivitis. Collapse or flattening of the trachea is common in turkeys and rare in chickens due to Bordetella avium. A tentative diagnosis of diseases of the respiratory system can be made based on history, clinical signs and gross and microscopic pathology. Confirmatory diagnosis can be made based on virus, bacterial and fungal isolation, serology, fluorescent antibody test, immunohistochemistry and Polymerase Chain Reaction (PCR). Epidemiology of a disease or a disease agent can be studied by sequencing or other molecular techniques of the etiologic agent such as IBV, ILT, MG, MS. Diagnosis of nutritional and toxicological diseases can be made by analyzing the feed or liver and serum from birds in certain diseases. The basic histopathological lesions of the respiratory system to injury are similar to those that occur in other organs in general and can be non-specific. However, according to one reference 82.3 % of the diagnosis of viral diseases in chickens may be made based on histopathological lesions or lack of them. In spite of such a high correlation histology provides guidelines as to possible etiology and it is important that isolation, molecular techniques and other tests should be done to confirm the diagnosis. Further the lesions in the respiratory tract can be complicated due to the involvement of multiple etiologic agents such as viruses, bacteria, fungi, parasites, nutritional deficiencies, ammonia exposure, etc. It should be stressed that it is extremely rare to find a single cause of respiratory disease but a combination of different etiologies when one is dealing with commercial poultry with clinical problems.

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The histopathological lesions seen in the avian respiratory system can be divided in to those that involve the epithelial cells and those that involve the lamina propria. Those changes that involve epithelial cells consist of loss of cilia, increased number of goblet cells, squamous metaplasia, hyperplasia and necrosis of epithelial cells. Other changes in the epithelial cells include viral inclusion bodies and attaching bacteria at the tips of the cells. The changes in the lamina propria include edema, hemorrhage, congestion of vessels, infiltration of inflammatory cells (heterophils, lymphocytes, plasma cells, macrophages, lymphofollicular reaction including lymphoid nodule formations), fibrosis, necrosis and hypertrophy of cells lining the mucous glands. Occasionally neoplastic lymphocytes can be observed in the lamina propria such as in Marek’s disease.

Catarrhal sinusitis/rhinitis, tracheitis, bronchitis and conjunctivitis are primarily seen in acute mild or transient viral infections without complications by bacteria such as E. coli and others or ammonia. Examples include Infectious bronchitis virus (IBV), Avian Paramyxovirus (APMV-1), low pathogenic avian influenza (LPAI), mild form of Infectious Laryngotracheitis (“Silent ILT”), avian metapnuemovirus, Histologically the lesions include deciliation in the trachea and and primarily lymphoplasmacytic inflammation of the mucosa in the upper respiratory tract and bronchus and conjunctiva.. Occasionally interstitial pneumonia characterized by infiltration of lymphocytes can be observed with IBV and APMV-1. In cases such as in Newcastle disease, highly pathogenic avian influenza (HPAI) due to serotypes H5 and H7 including Bird flu (H5N1) and infectious laryngotracheitis (ILT) hemorrhages alone or in combination with fibrinonecrotic exudate can be seen in the conjunctiva and upper respiratory tract. . In cases of ILT, syncytia with intranuclear inclusion bodies can be observed in the mucosa or in the sloughed cells of the lumen most commonly in the upper respiratory tract. Similar lesions can also be seen commonly in the conjunctiva and also in the bronchi. In cases of poxvirus infection, lesions are usually seen in the upper respiratory tract and conjunctiva and the lesions are generally proliferation of epithelial cells many of which contain eosinophilic intracytoplasmic inclusion bodies. It is not uncommon to find intranuclear inclusions in the epithelial cells of the upper respiratory tract of young turkeys.

In uncomplicated cases of mycoplasmosis in chickens and turkeys the histological lesions tend to be lymphoplasmacytic inflammation of the upper and lower respiratory tracts including the air sacs and formation of lymphoid nodules in subacute to chronic cases. Lesions due to E. coli in the air sacs and pleura are usually fibrinosuppurative in nature. However, E. coli and other bacteria such as P. multocida, Staphylococcus aureus , M. avium cand other bacteria causes granulomatous inflammation characterized by a focus of caseous necrsosis in the centre which in turn is surrounded by mulinucelated giant cells that are often associated with a few to numerous bacteria. Similar lesions can also be observed in the lungs and air sacs and sometiems in the syrinx due to aspergillosis associated with intralesional fungi. Congestion, edema and fibrinosuppurative inflammaiton can be seen in birds infected with Ornithobacterium rhinotracheale. Pulmonary edema and congestion can also be observed in chcikens and turkeys Below is a list of various agents and diseases that can cause respiratory disease in chickens and turkeys: Viruses Infectious bronchitis - Coronavirus Avan Paramyxovirus -1 and Newcastle disease Avan Paramyxoviruses- 2 and 3. Avian influenza - Orthomyxovirus Infectious Laryngotracheitis (ILT) – Gallid herpersvirus 1. Swollen head syndrome/Turkey rhino tracheitis – Avina Metapneumovirus. Fowl Pox – Poxvirrus Adenovirus (Group II in turkeys) Reovirus Marek’s disease – Herpersvirus (lymphoma in lungs), etc.

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Retrovirus (J virus) Bacteria: Salmonella sp. (S. Pullorum/ S. Gallinarum.) E. coli (Colibacillosis) Mycoplasma gallisepticum Mycoplasma synoviae Mycoplasma meleagridis (turkeys) Pasteurella multocida Ornithobacterium rhinotracheale Avibacterium paragallianrum Bordetella avium (B. hinzii occasionally) Staphylococcus aureus (tyrkey poults) Gallibacterium anatis Riemerella anatipestifer (Ducks and turkeys) Chlamydophila psittaci (turkeys) Streptococcu sp. Pseudomonas aeruginosa Mycobacterium avium Others: Fungi: Aspergillus (A. fumigatus, A. flavus)

Ochroconis (Previously Dactylaria) Parasites: Cryptosporidiosis Leucocytozoon sp. Neoplasia Lymphoma (Marek’s and retroviruses) Bronchogenic carcinoma Metastatic adenocarcinoma from ovary, etc. Hemangioma/sarcoma Sarcoma’s, adenoma’s and others Nutritional: Vitamin A deficency Toxic: Ammonia Teflon (Polytetrafluoroethylene - PTFE) Cotton defoliants Ionophores (degeneration of tracheal muscles) Formaldehyde Metabolic/genetics: Pulmonary hypertension syndrome (Ascites) Dilated cardiomyopathy Others: Trauma Foreign bodies (plnat material/feed, dust, carbon, etc.)

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Hypersensitivity (Anaphylactic shock) Faulty and spray vaccination Others. References:

1. Fletcher, O. J. Pathology of the Avian Respiratory System. Poultry Science. 59:2666-2679. 1980. 2. Fletcher, O. J, T. Abdul-Aziz and H. J. Barnes. Respiratory System. In:. Avian Histopathology.

59:129-163. 2008. 3. Franca, M., P. R. Woolcock., M. Yu, M. Jackwood and H. L. Shivaprasad. Nephritis associated with

Infectious Bronchitis virus variant Cal99 in game chickens. Avian Diseases. 55:422-428.

2011.Garside J. S. The histopathological diagnosis of Avian Respiratory Infections. The Veterinary Record. 77:354-366. 1965.

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Etiologies for Neurological signs (and for neuritis-see page 66) in Poultry

Malformations: Encephalocele (Silky, Polish, etc.) Hydrocephalus Hydranencephaly Cerebral/cerebellar Hypoplasia Metabolic/genetics: Peripheral neuropathy (WLH chickens – B*19 haplotype) Mucopolysaccharidosis type IIIB – Emu’s Paroxysmal chicks Congenital Loco Scoliosis Epilepsy (Silky, Fayoumi) Hypoglycemia Bacteria: Salmonella sp. (S. arizonae, S. Pullorum, S. Typhimurium, etc.) E. coli Clostridium botulinum Mycoplasma gallisepticum Mycoplasma synoviae Riemerella anatipestifer Chlamydophila psittaci Enterococcus hirae Listeria monocytogenes Pasteurella multocida Ornithobacterium rhinotracheale Staphylococcus sp. Streptococcu sp. Pseudomonas aeruginosa Viruses Avian influenza - Orthomyxovirus Avian encephalomyelitis - Picornavirus APMV-1 – Newcastle disease Marek’s disease - Herpersvirus Reticuloendotheliosis group – Retrovirus Avian Lymphoid Leukosis group – Retrovirus (RAV-4, ALV-J)

- ALV- A (cerebellar hypoplasia, glioma, astrocytoma) Reovirus Parvovirus (cerebellar hypoplasia) Bunyavirus (ostrich) EEE – Alphavirus WEE – Alphavirus Highland J virus - Alpha virus Israel turkey meningoencephalitis virus – Flavivirus West Nile virus (geese) - Flavivirus

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Fungi: Aspergillus (A. fumigatus, A. flavus) Ochroconis (Previously Dactylaria) Zygomyces Parasites: Sarcocystis Toxoplasma Trichomonas Malaria Haemoproteus (Quail) Cerebrospinal nematodiasis Schistosoma Neoplastic Lymphoma (Marek’s) Glioma’s (Retrovirus) Pinealoma Astrocytoma (Retrovirus) Choroid plexus carcinoma Nutritional: Vitamin E Vitamin B1 Vitamin B2 Vitamin B6 Thiamin Pantothenic acid Folic acid Biotin Vitamin B12 Toxic: Salt Organophosphates Carbamates Hydrocarbons Lead Ionophores (Monensin, Lasalocid) Arsenilic acid Zinc Mercury Amprolium Dinitolomide (coccidiostat) Avian Vacuolar Myelinopathy (Hydrilla sp.) Poison Hemlock Others: Trauma Faulty vaccination Degenerative Myelopathy Spondolisthesis Spondylitis

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Vascular problems Etiologies for Neuritis in Chickens: Viruses/diseases: Marek’s disease (Herpesvirus) Retroviruses: Reticuloendotheliosis virus and ALV – J Newcastle disease (END) - Avian Paramyxovirus-1 Highly pathogenic Avian Influenza (Orthomyxovirus) Reovirus (CNS signs) Bacteria: rare Parasites: Toxoplasma Nutritional: Riboflavin (B6) Thiamin (B1) Perosis (Niacin, pantothenic acid, Vit. B12) Others? Toxic: Lead, mercury, organic arsenicals Organo phosphates, Chlorinated hydrocarbons Ionophores – Lasalocid, Monensin Genetic: Peripheral neuropathy (WLH chicken, B19 haplotype Others: Faulty vaccination

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Avian Integument – outline of Anatomy and Diseases

(Acknowledgement: Dr. John Barnes, Professor Avian Pathology, North Carolina State University, Raleigh,

NC)

A) Avian Integument – Introduction

Forms the external layer of the body and is composed of skin, feathers and other structures

Skin and Feathers – unique structures with many adaptations

Feathers – Unique to birds and are a prominent feature of birds anatomy

Variation in color and types

Insulation, flight, appearance, camouflage, secondary sexual characteristics, water repellent

Use in culture, religion, human use, etc.

Other Structures – include beak, nails, comb, wattle, snood (turkeys), ear lobes, cere, shields (coots, gallinules), knob (goose), casque (cassawaries), helmet (guinea fowl), modified comb such as head plumage (crests, bristles), scales (shank and feet), webbing in feet (ducks), foot pads and glands (uropygial gland near the tail and glands in the external ear)

Skin, beak, nails and feathers – present in all birds. These vary in pigmentation, shape, texture, function, location and number

B) Anatomy – Salient features

Structure

Epidermis

Stratum corneum

Stratum germinativum

S. transitivum

S. spinosum

S. basale

Dermis

Superficial

Deep

S. compactum (dense layer)

S. laxum (loose layer; apterial muscles)

Loose dermis permits accumulations of fluid (edema), blood (hematoma), and exudate (cellulitis) beneath the epidermis

Herbst corpuscles (pressure receptors) present in dermis adjacent to feathers

Subcutis (subcutaneous fat and muscles)

Fat pads found in specific areas of body

Vascular beds in dermis of legs for heat conservation

Penguins brood eggs on feet

Erectile tissue often present in facial appendages

Characteristics of avian skin

Feathers instead of hair, feathered (pterylae) and unfeathered tracts or regions (apteria)

Remiges (primary and secondary flight feathers)

Tectrices (contour feathers that cover the bases of the flight feathers)

Rectrices (tail feathers)

No adnexal glands; uropygial (preen) gland at base of tail (holocrine, not present in all avian species), cerumen glands in ear canal, few glands around vent; entire skin surface is secretory

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Thin; rete pegs absent or reduced except at certain dermo-epidermal junctions

Scales (scutes [scuta], scutella, reticula, cancella), horny structures, and appendages (wattles, snood, comb, ear lobes, etc.)

Specialized areas of integument

Rictus – commissure of beak

Facial appendages; highly vascularized, erectile, heat exchange, display

Foot pads; spurs (calcaria); claws (ungues), scales (podotheca – unfeathered, scaled skin of the foot)

Beak (rhamphotheca) – thick keratin and free and keratin-bound calcium

Cere – base of upper beak

Egg tooth – on tip of beak of newly hatched bird

Sensory receptors

Herbst corpuscles – mechanoreceptors, numerous in beak

Grandry corpuscles (beak tip, aquatic birds)

Merkel cells

Brood patches – highly vascularized area in abdominal skin; present in both males and females

Feathers

Invagination of epidermis into dermis

Arrangement

Pterylae – feather tracts

Apterylae – area without feathers

Pterylosis – implantation point of each feather follicle in the skin

Types

Contour – majority of the body

Coverts – on the wings, tail and around ears

Remiges – primary and secondary feathers of wings

Retrices – large flight feathers of the tail

Downs – small and fluffy feathers with a very short or absent rachis. Natal downs are present at or soon after hatch. Definitive downs occur on various parts of the body as part of immature and adult plumage.

Powder downs - specialized down feathers that disintegrate producing powder (keratin). Not present in all birds.

Semiplumes – feathers with a long rachis

Bristles – stiff, tapered rachis with no barbs

Filoplumes – fine hair-like feathers

Structure

Calamus (quill)

Rachis (shaft)

Vane

barb

barbule

Dermal papilla, epidermal collar

Umbilicus (proximal, distal also superior, inferior)

Pulp caps

Degeneration, necrosis, edema, and hemorrhage normal immediately subjacent to pulp cap; inflammation in deeper pulp is abnormal

Sternal bursa – synovial structure in subcutis over anterior keel of chickens and turkeys (see musculoskeletal system), develops with age

Functions of integument

Resistance to infection; normal avian skin remarkably resistant

Temperature control (cooling primarily via respiratory system)

Display – mating, social rank, etc.

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Flight; diving

Sensory perception C) Diseases

Has not received extensive studies nor well characterized Reasons:

Wide variation in anatomy of skin and its appendages Large numbers of species of birds (9300 species, more than 22,000 subspecies,166 families in 27

orders) Few primary skin and feather conditions Lack of knowledge or observation of diseases Lesions hidden by feathers Reagents (IHC, FA) not easily available Difficulty in fixation – skin tends to curl-up and feathers tend to float in formalin Extra organ to deal with Does not explain the cause of death most of the time Prone to trauma Value of the bird Economics (individual ‘vs’ flock; cellulitis, squamous cell carcinoma, Marek’s disease in broiler

chickens, tumors in pet/exotic birds, etc.) Undesirable traits eliminated at primary breeder level Paucity of pathologists/histopathologists

Factors which influence diseases

Management and environment

Poultry raised in commercial or back yard setting

Pet and exotic birds – aviary, pet shops or individual pet birds

Free flying birds

Birds in captivity (zoos)

Genetics and nutrition

Disease agent (virus, bacteria, parasites, etc.)

Diseases of the integument can be primary or secondary to systemic diseases or disease of specific organ such as liver, pancreas, kidneys, gastrointestinal, hemopoietic, endocrine, etc.

Malnutrition probably plays a big role in diseases of the integument – diseases of malnutrition are probably underdiagnosed

D) Avian Reaction to tissue injury - Inflammation

Reaction is rapid in birds, 36 hours

Leakage of fibrin and fibrinogen common in early exudate

Intense granulomatous reaction (12 hours)

Coagulum of eosinophilic debris, degranulating heterophils, macrophages and giant cells

Macrophages, heterophils and thrombocytes are active phagocytes

Pus is caseous but liquefaction can occur

Birds respond with granulomatous inflammation to many insults

Acute inflammatory reaction in birds involve edema, congestion and vascular changes mediated by basophils and mast cells

1-3 hours: basophils, heterophils and monocytes

2-6 hours: basophils degranulate and die

6-12 hours: lymphocytes, monocytes, macrophages

12-36 hours: lymphocytes, macrophages, giant cells

Acute reaction peak by 12 hours (when giant cells appear)

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36-72 hours: regeneration and repair

Fibroblasts, secondary lymphoid follicles, plasma cells

Chronic reaction with caseation, macrophages, giant cells, granuloma formation

Cells involved in inflammation

Heterophils: have lance-shaped granules, lack myeloperoxidase and alkaline phosphatase, have -glucuronidase and acid phosphatase

Very phagocytic

Granules tend to round up in tissues, difficult to identify

Eosinophils: have spherical granules

Function is not known, delayed type IV hypersensitivity?

Associated with eosinophilic enteritis in turkeys due to ascarid

Basophils: contain histamine, involved in acute inflammation

Thrombocytes: small round to oval cells with clear cytoplasm and small round nucleus (looks like small lymphocyte), phagocytic

Monocytes: precursors to cells of MPS, phagocytic, can fuse to form multinucleated giant cells

Make monokines; IL-1, IL-2, (IL-4?), IL-6, IL-8, (IL-10?), (IL-12?), IL-15, IL-16, IL-17, IL-18, TNF, G-CSF, gamma interferon

Lymphocytes: various morphologies involved in subacute inflammation including plasma cells Coagulation

Extrinsic system active and efficient but intrinsic system relatively weak

Tissue thromboplastin (III) and platelets play important role

Has a vitamin K dependent factor similar to mammalian factor IX

Plasma thromboplastin and Hageman factor may be lacking

Low levels or absence of factors V and VII

Fibrinogen (I), prothrombin (II), antihemophiliac factor (VIII) and Stuart factor (X) are present

Clot retraction is very slow in birds

Has thrombolytic mechanism and t-PA activation for fibrinolysis Complement

Not well understood

Classical complement (CCP) and alternate complement pathways (ACP) are present

A few components have been identified such as C1, C3, B

may lack C2 and C4.

Factor B in chickens may play a dual role in ACP and substituting for C2 in CCP

Differences in C components may exist among avian species

E) Avian skin reaction to injury: Acanthosis, Acantholysis, hyperkeratosis, parakeratosis, dyskeratosis, hypertrophy, ballooning degeneration, hyperplasia, spongiosis, macule, papule, pustule(?), ulceration, fibrinosuppurative or fibrinoheterophilic, granulomatous, etc.

Genetic Diseases

Avian Ichthyosis (chicken)

Scleroderma (UCD - L200, White Leghorn Chicken)

Autoimmune Vitiligo (Smyth line chicken)

Albinism

Others

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Bacterial Diseases

Gangrenous dermatitis – clostridia (usually C. septicum; C. chauvoei and C. perfringens less common), Staphylococcus, other bacteria; follows wounds

Immunosuppression a common predisposing factor (infectious bursal disease and/or chicken infectious anemia in chickens)

Erysipelas (Erysipelothrix rhusiopathiae) – trauma, wounds, vasculitis, thrombosis.

Fowl cholera – chronic, chickens, abscesses in facial appendages. Similar lesions also can by caused by Staphylococcus.

Cellulitis

Inflammatory Process (“Cellulitis”); Chickens; E. coli infection

Turkeys; fowl cholera; Clostridium perfringens Type A involving tail

Chickens; swollen head syndrome – viral/bacterial interaction, E. coli

Dermatitis – Staphylococcus, E. coli common causes; acute, edematous lesions typical of Pseudomonas infection

"Necrotic" dermatitis of turkeys

Folliculitis – bacterial infections, usually caused by staphylococci

Pododermatitis – trauma, contact with wet litter

‘Bumblefoot’ – foot pad abscess, trauma, staphylococci

Other

Mycobacteriosis – psittacines and ratites, often periorbital, M. tuberculosis (human TB), M. avium, or M. genavense; local invasion or systemic disease; focal, multifocal or diffuse thickening of skin; histiocytes (‘epitheliod cells’), occ. giant cells histiocytic granulomas, caseous necrosis, acid-fast bacilli

Actinomycosis – granulomas

Virulent Mycoplasma synoviae (vasculitis)

Mycoplasma iowae "clubbed" down in embryo (also seen in riboflavin deficiency and overcrowding during incubation)

Mycotic Diseases

Favus – Microsporum gallinae

Yeast infections

Rhodotorula

Candida sp. (C. albicans, C. glabrata, etc.)

Candidiasis – foot pad ulceration, dermatitis

Keratinophilic mycosis of turkeys ("Scurfy Dermatosis") – organisms morphologically compatible with Malassezia

Mycotic dermatitis – Aspergillus, Mucor, Candida

Nodular dermatomycosis – Candida + Aspergillus

Geotrichum – necrosis and dermatitis of feet and legs of flamingos

Feather mycosis

Superficial mycosis of turkeys

Penicillium cylcopium – beak infection Macaw

Cutaneous rhinosporidiosis – swans

Viral Diseases

Avian pox: not the same as chicken pox in humans, which is caused by a herpes virus.

Dry form - Lesions generally occur in unfeathered areas of the skin

Wet form occurs in the mucus membranes of the digestive and reproductive systems).

Occasionally lesions in feathered parts of the body

Characteristic histologic changes

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Epithelial cell hyperplasia

Ballooning degeneration

Eosinophilic intracytoplasmic inclusions (Bollinger bodies)

Virulent influenza/Newcastle disease viruses

Vesicles rupture to form ulcers

Edema, hyperemia, hemorrhage due to vasculitis

Pigeon Paramyxovirus – Folliculitis

Swollen head syndrome – infectious bronchitis virus (coronavirus), avian metapneumovirus secondary bacterial infection facial cellulitis (see C.4)

Marek's disease – skin form

Intranuclear inclusions in epidermal cells

Lymphoid foci in dermis associated with follicles; initially inflammatory (small lymphocytes primarily) followed by transformation (pleomorphic lymphocytes including blast cells); normal tissue invaded and replaced

Pulpitis

Other cutaneous or blepharitis herpesvirus infections

Pacheco’s disease – small skin ulcers, blepharoconjunctivitis, typical inclusions present

Cytomegalic-like herpesvirus infection – cockatoos & macaws most affected, proliferative nodules or flattened plaques on feet and legs, epidermal hyperplasia, acanthosis, large intranuclear inclusion bodies surrounded by a clear zone

Herpesvirus infection in finches – blepharitis and conjunctivitis. Large cytomegalic cells with intranuclear inclusions

Pigeon herpesvirus – blepharoconjunctivitis with intranuclear inclusions

Infectious laryngotracheitis of chickens - blepharoconjunctivitis with intranuclear inclusions

West Nile virus – folliculitis in psittacines, canaries and others

Avian leukosis virus

Lymphosarcoma – dermal

Hemangiomas

Myeloid leukosis – feather pulp

"Nakanuke" – feathering defect caused by reticuloendotheliosis virus, post-cyclophosphamide treatment, radiation, T2 toxin, etc.

Rous sarcoma (transmissible myxosarcoma) – interaction with trauma/ inflammation

Chick anemia virus – blue wing disease (type of severe gangrenous dermatitis)

Hemorrhagic enteritis virus (Type II adenovirus) – SQ hemorrhages, turkeys

Malabsorption syndrome/Poult enteritis complex – poor feathering & skin pigmentation

Polyomavirus (Papovaviridae)

Budgerigar fledgling disease

Loss of feathers – “French Molt”

SQ hemorrhages

Karyomegalic intranuclear inclusion bodies in feather follicle and epidermal cells

Hemorrhagic nephritis enteritis of geese

SQ edema and ascites

Viral papillomas – papovaviruses

Passerines -- feet, rictus, face

African grey parrot -- proliferative skin lesions, hyperplastic epithelium, large nuclei but no distinct inclusion bodies, virus on EM

Cloacal papilloma’s – associated with herpesvirus-like and herpesvirus sequences

Psittacine beak & feather disease (avian circovirus) – feather and beak abnormalities, large basophilic (morula/botryoid) intracytoplasmic inclusions in feather epithelium and pulp, intranuclear inclusions less common. Also inclusions in the epidermal cells.

Infectious bill atrophy – parvovirus, ducklings (see Digestive 1)

Calicivirus – vesicular lesions; white tern chick

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Parasites

Malaria (Plasmodium) – dermatitis of eyelids

Leucocytozoon – meronts in feather pulp

Sarcocystosis – folliculitis in a psittacine

Fowl mites

Dermanyssus

Ornithonyssus

Uropodidae – pseudoparasites, harmless scavenger mites

Scaly leg, scaly face, “Tassel foot”, and depluming mites; Knemidocoptes spp.

Epidermoptic mites

Myialges spp.

Epidermoptes bilobatus

Microlichus avus

Trombiculidae (chigger) infestation

Quill, feather mites (Analgesidae, Pterolichidae, Proctorphyllodidae, Cheyletidae)

Subcutaneous mites – Laminosioptes cysticola

Fowl ticks

Soft ticks – Argas spp., Ornithodoros spp. less common

Hard ticks – primarily "seed" ticks

Tick paralysis can occur

Mortality from hemorrhage & blood loss

Vector for disease organisms, esp. Borrelia, Aegyptianella

Lice – all chewing lice in order Mallophaga; numerous genera and species

Stick-tight flea – Echidnophaga gallinacea

Biting insects

Bugs – bedbugs, assassin bugs, bird bugs

Fire Ants

Diptera

mosquitos – arboviruses, poxvirus, malaria (Plasmodium)

biting midges (Culicoides) – Haemoproteus vector

black flies (Simulidae) – Leucocytozoon vector, filarids

louse flies (Hippoboscidae) – Haemoproteus vector

others – most biting flies will attack birds

Myiasis – ear canal of owls, nestlings Protocalliphora; bluebirds Philornis; wound myiasis, geese, turkeys, Wohlfahrtia, Lucilla

Leeches – also mucosal surfaces (mouth, eye, nares, pharynx, etc.-caused by species in genus Theromyzon)

Skin fluke – Collyriculum

Cercarial dermatitis – Trichobilharzia, ducks (Blair & Islam, 1983)

Subcutaneous filarids

Avioserpens - SQ fibrous tumors in ducks

Ornithofilaria - ducks & geese

Pelecitus - pigeons, psittacines

Singhfilaria - wild turkeys & quail

Splendidofilaria - grouse Nutrition/Metabolic

Calcium/vitamin D3 deficiencies – rickets, beak flexibility

B-vitamin deficiencies – marked acanthosis, hyperkeratosis, crust formation, secondary bacterial infections, assoc. dermal inflammation. Commissure of mouth, scales, and feet affected.

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Biotin deficiency – moderate to marked lesions; hyperkeratosis; parakeratosis absent to minimal

Niacin deficiency – mild to moderate lesions

Pantothenic acid deficiency – hyperkeratosis and parakeratosis

Riboflavin deficiency – clubbed down, embryo

Lysine deficiency

Amino acid deficiency

“Dry Wing" in ducks

Vitamin A deficiency – plantar corn, "bumblefoot" , hyperkeratosis – epidermis and feather follicles, squamous metaplasia, glands of the external ear

Vitamin E deficiency

Exudative diathesis

Pansteatitis (see also fatty liver-kidney syndrome)

Feather achromia – deficiencies of lysine, folic acid, iron (fowl), choline, riboflavin (cockatiel)

Segmental dysplasia – "stress marks"; indicative of episodes of acute stress; experimentally induced by single injections of glucocorticoids, which decreases growth and increases protein breakdown

Zinc deficiency – feathers involved; hyperkeratosis follicle atrophy fibrosis results in feather atrophy and loss

Xanthoma and xanthomatosis; cholesteomas

Fatty liver-kidney syndrome – congested ("pink") SQ fat

Halofuginone (coccidiostat) – decreased skin strength, increased tears; Mechanism: interference with incorporation of proline in collagen

Hypothyroidism – feather loss, atrophy of skin and feather follicles, silki feathers in ‘Obese’ strain of chicken (model for autoimmune thyroioditis)

Atherosclerosis of axial artery in the pulp – manifestation of atherosclerosis of major vessels and other vessels in a psittacine

Feather loss – androgen or estrogen deficiencies

Chronic liver disease – associated with beak overgrowth

Calcinosis circumscripta – focal to multifocal circumscribed focal to coalescing, soft, white, chalk-like deposits

Neoplasia (see also Marek’s disease, LL, REV)

Papillomas – viral etiology in African grey parrots (papillomavirus). Herpesvirus-like and herpesvirus sequences associated with cloacal papilloma’s

Squamous cell carcinoma

Dermal squamous cell carcinoma ("keratoacanthoma"); chickens, lesions spontaneously regress, genetic predisposition

Uropygial gland – differentiate from adenocarcinomas

Beak – typical tumor, germinal area along margin

Uropygial gland adenoma/adenocarcinoma

Basal cell tumors (pteryloepithelioma [‘feather folliculoma’], carcinomas (rare)

Lipoma/liposarcoma (lipomas common, liposarcomas rare)

Osteolipoma

Hemangiolipoma

Myelolipoma (see Hemopoietic & Lymphoid System)

Hemangioma / hemangiosarcoma

Fibroma / fibrosarcoma / myxofibroma /myxoma

Malignant melanoma – beak margin, typically pigmented

Undifferentiated sarcoma/other sarcomas – can be assoc. with tattoos

Other

Hemangiopericytoma

Mastocytoma

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Malignant melanoma

Granular cell tumors – PAS+ cytoplasmic granules

Teratoma – subcutaneous tissue in an African Grey Parrot

Undifferentiated neoplasia Toxicities

Photosensitization – plants of genera Ammi and Cymopterus

Vesicular dermatitis – ergot

Ulcerative dermatitis – trichothecene mycotoxins

Radiomimetic feather lesions (“nakanuke”) – trichothecene mycotoxins

Fire ant (Solenopsus invicta) stings

Selenium toxicosis – acquired beak deformities

Ammonia - blepharoconjunctivitis Management

Hyperproteinemia from high humidity in hatcher

Dry gangrene – frostbite, other; sloughing of affected tissues

Burns/trauma/cold/other physical agents [microwave radiation] – coagulative necrosis, zone of demarcation between affected and unaffected tissue; inflammation, hemorrhage, etc.

Bruising – green discoloration; hemoglobin --> biliverdin

Feather picking

Persecution/cannibalism

Predation

Foreign bodies

Lacerations/punctures

Contact dermatitis – moisture

Scabby hip syndrome

Focal ulcerative dermatitis – turkeys

Pododermatitis

“Galls”

Poisonous bites and stings

Granulomatous cellulitis – cervical, tail, oil emulsion vaccines

Beak necrosis

Overgrowth of beak, nails

Lipogranulomas – obesity

Sternal bursitis (non-infectious)

Dehydration Unknown/Other

Feather follicle cysts (folliculomas) – genetic in certain strains of canaries

Epidermal inclusion cysts – filled with keratin; neck, breast, and back of older laying hens

Follicular keratosis – atrophy of feather, follicle fills with keratin from follicular epithelium and becomes distended

Frizzle feather and other genetic feather disorders

Slow feathering

Subcutaneous emphysema

Congenital baldness (apterylosis)

Cyanosis, anemia, icterus, methemoglobinemia, dehydration, etc.

Melanosis – abnormal green to gray discoloration of shanks and black pigmentation of abdominal wall

Eosinophilia/facial edema

Allergies – cutaneous hypersensitivity, Arthus reaction

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Amazon foot necrosis – self-mutilation possibly due to delayed hypersensitivity reaction Perivascular and/or perifollicular lymphoid and plasma cell infiltrates are common in birds with

idiopathic skin diseases

Cere hyperkeratosis (brown atrophy) – normal with aging in many species especially budgerigars

Foot/toe pad hyperkeratosis

Ichthyosis

Dermolytic mechanobullous disease – ostriches, genetic?

Vent gleet – associated with respiratory disease, acidic urine

Preen gland adenitis – ducks, cause?

Polyfolliculosis – multiple feathers from one follicle, psittacines, pruritis clinically

Constricted toe syndrome – nestling parrots affected; band of connective tissue encircles a toe impairing circulation and resulting in necrosis

Collagen lysis – breakdown of collagen provokes an intense granulocytic (? eosinophilic) reaction

Split wing syndrome References:

1. Barnes, J. E. Avian Pathology, Class notes. College of Veterinary Medicine, North Carolina State University, Raleigh, NC.

2. Lowenstine, L. J and others. Comparative Avian Anatomy and Pathology, Class notes. School of Veterinary Medicine, University of California, Davis, CA.

3. Avian Histopathology, 1996, Ed. C. Riddell, 2nd Ed, AAAP pub. Kennett Square, PA 4. Color Atlas of Avian Histopathology, 1996, C.J. Randall and R.L. Reece, Mosby-Wolfe 5. Diseases of Poultry, 2003, Ed. Y. M. Saif, et al., Iowa State Press, Ames, Iowa 6. Color Atlas of Diseases and Disorders of the Domestic Fowl, 1991, C.J. Randall, Iowa State

University Press, Ames, Iowa 7. Avian Medicine: Principles and application, 1994, Ed. B. W. Ritchie, G.J. Harrison and L.R.Harrison,

Wingers publishing, Lakeworth, FL 8. Pathology of Zoo Animals, 1983, L. A. Griner, Zoological society of San Diego, CA 9. The comparative Pathology of Zoo Animals, 1980, Ed. R. J. Montali and G. Migaki, Smithsonian

Institution Press, Washington, DC. 10. Field manual of Wildlife Diseases: General Field procedures and diseases of migratory birds, 2001,

Ed. M. Friend, US dept. Interior, Fish and Wildlife Service pub, Washington, DC. 11. Diseases of Cage and Aviary birds, 1996, W. J. Rosskopf and R.W. Woerpel, Williams and Wilkins,

PA 12. Diseases of Wild waterfowl, 1981, G.A. Wobeser, Plenum Press, NY 13. Pathology of Pet and Aviary Birds, 2003. R. E. Schmidt, D. R. Reavill and D. N. Phalen. Blackwell

Publishing, Oxford, UK. 14. Pass, D.A. The pathology of the avian integument: a review. Avian Pathol 18:1-72, 1989. 15. Shivaprasad, H. L. An overview of bird pathology – outline.

Journals: Avian Pathology, Avian Diseases, Veterinary Pathology, J Comparative Pathology, Veterinary Record, JAVMA, AJVR, JAMS, Poultry Sci., etc.

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Table 1. Mites in Birds (Note: many others are not listed)

Name Common Name Species of birds affected

Dermanyssus gallinae* Red mite (Roost mite, Poultry mite)

Chickens, turkeys, pigeons, canaries, wild birds

Ornithonyssus sylviarum* Northern Fowl mite Chicken, turkeys, wild birds

O. bursa Tropical Fowl mite Poultry, pigeons, Mynah

Knemidocoptes mutans* Scaly-leg and scaly-face mites Poultry

K. pilae* Scaly-leg and scaly-face mites Psittacines

Procnemidokoptes janssensi Scaly-leg and scaly-face mites Love birds

K. jamaicensis Scaly leg mite Canaries, finches, other passerines

Knemidocoptes gallinae Depluming mite Chickens, pigeons, pheasants

K. laevis Depluming mite Pigeons

Neocnemidocoptes gallinae Depluming mite Pheasants and others

Epidermoptes bilobatus Skin mite Chickens

Myialges nudus Skin mite Grey-cheeked parakeets

Harpyrynchus sp. Skin and feathers Passerines

Syringophilus hipectinatus Feather and quill mites Poultry, wild birds

columbae Feather and quill mites Pigeons

(Dermoglyphus sp., Analges sp., Mengninia sp., Freyana sp)

Feather and quill mites Chickens, turkeys

Paraglopsis sp. Feather and quill mites Psittacines, finches

Sternostoma tracheacolum* (Neonyssus, Rhinonyssus)

Respiratory tract mite (trachea, lung, air sac)

Passerines (canaries, finches), psittacines, poultry, pigeon

Cytodites Air sac mite (bronchi, lungs, air sac)

Poultry, pheasants, pigeons, canaries, etc.

Laminosioptes cysticola Cyst mite (skin, subcutis, muscle, abdominal viscera and lungs)

Chicken, turkeys, pigeons, pheasants geese

Hypopial mites Areolar subcutaneous, connective tissue

Pigeons

Family Trombiculidae (Neoschonagastia americana)

Chiggers Poultry (Southern US), turkeys, wild birds, chickens

* Most common

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Etiologies (Diseases) of the Immune System - An Outline

Bacteria Septicemia involving spleen, bursa of Fabricius, thymus and bone marrow

1. E. coli. 1. Salmonella sp. 2. Pasteurella multocida 3. Staphylococcus sp. 4. Streptococcus sp. 5. Mycobacterium avium 6. Yersinia psedutuberculosis 7. Others: Listeria

Fungus

1. Aspergillus fumigatus and A. flavus Virus

1. Marek’s disease 2. Infectious bursal disease (Birnavirus) 3. Chicken Infectious anemia (genus – Gyrovirus, family – Circoviridae) 4. Avian Leukosis (Retrovirus) 5. Reticuloendotheliosis (Retrovirus) 6. Exotic Newcastle disease 7. Highly pathogenic Avian Influenza 8. Hemorrhagic Enteritis of turkeys (Adenovirus Group II) 9. Marble Spleen Disease (Adenovirus Group II) 10. Reovirus isolates 11. Duck Enteritis (Herpesvirus) 12. Alphaviruses (Bunyavirus) 13. Turkey Coronavirus

Parasite

1. Cryptosporidia 2. Leucocytozoon 3. Malaria

Toxicity 1. Cyclophosphamide 2. Trichothecenes (T-2) 3. Aflatoxins 4. Lead 5. Sulfonamides

Nutrition

1. Vitamin A 2. Vitamin E/selenium

Neoplasia

1. Lymphoma 2. Thymoma

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3. Sarcoma 4. Carcinoma (serosal implantation) 5. Histiocytosis?

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Poultry Pathology of Special Senses

Birds in general have excellent visual and good auditory systems. They also have sense of smell (olfaction), taste (gustation), chemicals (chemesthesis mediated by trigeminal chemoreceptors), temperature and pressure mediated through various receptors. There are various receptors and types of corpuscles dsitributed thorugh out the body more numerous in some locations like skin, tongue, oral cavity, face, beak, head, etc. Four types of mechanosensitive sensory corpusles are found mostly in the skin of birds. These include Herbst corpuscles (similar to Pacinian corpuscles in mammals) most common in the skin, Merkel cell receptors, Grandri corpuscles in aquatic birds and Ruffini endings. There are also free nerve endings in the skin which are thought to serve thermoception and nociception (pain). Other than the pathology of visual and auditory senses very little is known about the pathology of other senses in birds. A Bird’s Eye View of Avian Ocular Anatomy and Diseases: 1. Characteristics Finest ocular organ in the animal kingdom Birds can recognize constellations for stellar orientation and navigation Have high resolving power for the perception of movements Excellent visual acuity Displays basic pattern of organization found in vertebrate eyes Has incorporated many adaptations to improve its visual abilities Birds are capable of

– color discrimination (Tetrachromatic color vision) – pattern recognition – vision in bright and dim light – under-water accomodation – sun orientation – UV light perception – spatial frequency (160 frames per second)

2. Anatomy –salient features Eyeball is accommodated in the spacious laterally directed orbit Its bony limits are formed by the lacrimal bone, the interorbital septum, the orbitosphenoid and the

parsorbitalis of the orbital bone There is a gap in the orbital ring, which is bridged by the ligamentum mandibulare longum Eyes are large and their shape can be flat, globose and tubular Scleral ossicles and cartilage present Striated muscles in iris and ciliary body Pectinate ligament is well developed Retina is thicker and has areas and fovea(s) Avascular (anangiotic) retina Afoveate, uni- or bifoveate retina Annular pad and a fluid-filled cleft in the lens Pecten is present Has large nictitating membrane Glandula lacrimalis, small or absent Gland of Harder present in the orbit, contains plasma cells in the interstitium Nasal gland present in the orbit

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There is no tapetum Conjunctiva associated lymphoid tissue (CALT)

a. Eye size Avian eye is both relatively large and absolutely large

– are large relative to the skull and has large orbit with displacement of the brain caudally – in a few birds, the combined weight of the eyes is greater than the weight of the brain

Largest eye of land vertebrates: ostrich – has bulbar axial length : 50 mm

Finches and warblers: 6 - 8 mm

b.Eye shape Three types:

– Globose: diurnal species; crow – Flat: majority of avian species – Tubular: owls and some eagles

Difference lies in the relative proportions of their axial and equatorial diameters Tubular eyes have the greatest visual acuity

c.Components EYEBALL (GLOBE) Made up of three tunics:

– External fibrous tunic - cornea and sclera – Middle vascular tunic (uvea) - iris, ciliary body and choroid – Internal sensory tunic - retina

Pectinate ligament Refractory media:

– Cornea – Aqueous humor – Lens – Vitreous body

External Fibrous tunic Sclera

– Consists of a cartilaginous lamina and a fibrous layer – Cartilaginous lamina attaches to the posterior portion of the scleral ossicles – Scleral ossicles:

Are a group of bones, which form a complete ring of overlapping plates. Vary in number between 10 - 18, majority have 15 Can be pneumatic in large eyes and vary in shape Reinforce the ciliary body Permit a more powerful accommodative function

Cornea – Is a refractive component made up of several layers:

1. The multilayered anterior epithelium 2. The anterior limiting membrane 3. The Bowman’s layer 4. The substantia propria 5. The posterior limiting membrane 6. The single layer posterior epithelium

Middle vascular tunic (tunica media) Iris - Regulates amount of light

– It is situated in front of the lens

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– It projects into and divides the space behind the cornea into anterior and the posterior chambers – Anteriorly covered by a single layer of epithelium – Posteriorly covered by two to several layers of pigmented epithelium. – Iris (cont) – The anterior and posterior layers enclose blood vessels, connective tissue and striated muscle

fibers – Two layers of muscle fibers; circular constrictor and radial dilator fibers – Color in iris

Dependent on amount and color of fat

Ciliary body - Accommodation – It is interspersed between the choroid and the iris – It is a ring-shaped plate, which carries numerous little folds, the ciliary processes – Its basal lamina contains muscles of accommodation and is attached along with the pectinate

ligament to the sclera – It contains numerous blood vessels and the stroma contains pigmented connective tissue – The ciliary processes as a whole form the corona ciliaris, gradually increase in height towards the

lens and fuse with the lens capsule

Choroid - nourishes retina – It is a black pigmented layer, which lines the greater part of the eyeball. It is made up of several

layers: 1. Lamina suprachoroidea - a loose structure containing pigment cells. It connects choroid to

the sclera 2. Lamina vasculosa - carries large blood vessels 3. Lamina capillarium - has dense capillary network 4. Lamina basalis - basal lamina

Internal sensory tunic Retina

– It is similar to other vertebrates in its organization and stratification – It is avascular in birds – It is a direct continuation of the brain and it consists of two parts:

1. An external nonsensory single layer of cuboidal epithelium containing pigment 2. An internal transparent, much thicker neuroepithelium, containing several types of neurons

and glial cells – Retina is relatively thicker in birds compared to other vertebrates (ten distinct layers):

1. The inner limiting membrane 2. The nerve fiber layer 3. The ganglion cell layer 4. The inner plexiform (reticular) layer 5. The internal nuclear layer 6. The external plexiform (reticular) layer 7. The external nuclear layer 8. The external limiting membrane 9. The layer of rods and cones

10. The pigment cell layer – It has fascinating array of photoreceptors, specialized areas, fovea(s), oil droplets, visual

pigments, and centrifugal fibers Areas represent as circumscribed thickenings of the sensory retina

Involves thinner and longer visual cells Helps in improved resolving power (visual acuity) Are well-developed in diurnal birds Can be present as single or two and sometimes three

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Are located in central (nasal) and lateral (temporal) areas Shape can be oval or circular and linear

Fovea is a depression within a central or lateral area or both Area may exist without a fovea, but a fovea is found only within an area Foveas are caused by a radial displacement of the more internal layers of the retinal area Results in shallow saucer-shaped or deeper funnel-shaped (convexiclivate) cavities Visual cell density is greater in the fovea than elsewhere in an area A 1:1 ratio between cones and ganglion cells can exist Deeper the fovea, the greater the magnifying power It is a sensitive directional focus indicator and may indirectly help in navigation

Pecten (pecten oculi)

– Is unique to birds – It is a vascular body projecting from the retina into the vitreous body at the point of exit of the

optic nerve – It consists almost exclusively of capillaries and extravascular pigmented stromal cells – It lacks both muscular and nervous tissue – Types of pecten – Three main morphological types of pecten are recognized:

1. Conical: recognized only in kiwis 2. Vaned: ostrich, rheas and tinamous 3. Pleated: rest of the avian species

– Functions of the pecten: Controversial. Some of the proposed functions are: 1. Nutritional – appears to be the primary function 2. Heating element of the eye 3. A movement detector by means of perceiving small shadows 4. A screen against bright light 5. A regulator of intraocular pressure 6. A sensor of magnetic fields 7. Improvement for visual acuity 8. A sextant to measure the angle of the elevation of the sun 9. Secretion (GAG’s) 10. Many others have been proposed

Pectinate ligament An extensive trabecular elastic fiber network better developed in avian species than in mammals This network bridges the angle between the cornea and iris and sclera and ciliary body The network is lined by endothelium and it encloses the space of Fontana, which forms the

connection between the chambers of the eye and the canal of Schlemm Canal of Schlemm is a circle of veins within the sclera by which aqueous humor is returned to the

blood circulation

Refractory media Cornea (see above) Lens

– Transparent and biconvex – Posterior surface more convex than anterior surface – Shape can be altered and has a homogenous capsule – Anterior surface has a single layer of cuboidal or columnar epithelium, which increase in length

towards the equator until they finally become hexagonal prisms – These prisms combine to form the annular pad, which surrounds the equator of the lens like a

belt – Fully mature prismatic cells retain their nuclei, whereas cells forming the body of the lens lose

their nuclei as they develop into the elongated lens fibers

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– Fluid-filled cleft is present between the annular pad and the body of the lens Vitreous body

– It is a gelatinous transparent body, which fills the space in the bulbus behind the lens and the ciliary body

– Its function is to stabilize the internal pressure of the bulbus – Its fluid component amounts to more than 90% of its total mass – The stroma consists of delicate branching fibrils which condense to form the membrana vitrea

OPTIC NERVE ACCESSORY ORGANS Eyelids

– Feathered (e.g., ostriches, rheas, and owls) or unfeathered in pigeons, parrots and passeriformes – Two eyelids

Upper eyelid Short and thick

Lower eyelid Longer, thinner, and highly mobile Supported by a connective tissue plate situated between the skin and conjunctiva

– Nictitating membrane (third eyelid) It is a conjunctival fold, transparent to opaque and milky white in color It is elastic and forms a pouch in which eye sits The membrane moves transversally across the front of the eye In pigeons, the corneal surface has cilia, which act as a delicate brush

Glands – Gland of the nictitating membrane (Harder’s gland)

Gland is large and irregular in shape and extends on the nasal side of the orbit It secretes into the space between the eyeball and the nictitating membrane, the conjunctival

sac Has large number of plasma cells in the interstitium producing antibody

– Nasal or salt gland: present in the orbit but not a part of the lacrimal apparatus (supraorbital gland - marine birds) Lies dorsomedially to the eyeball and it is ovoid and yellowish Its duct pierces the frontal bone and enters the nasal cavity It excretes hypertonic salt solutions, presumably through a stimulus from the osmolality of

the plasma Lacrimal apparatus or gland

– Located in the ventrotemporal part of the orbit and is covered by conjunctiva – Its secretion empties directly beneath the lower eyelid – It may have single duct or multiple ducts – It is small in aquatic birds, large in others and absent in owls

Orbital fasciae Oculomotor muscles

– Four straight - globe – Two oblique - globe – Several - eyelid

Conjunctiva associated lymphoid tissue (CALT) – Component of mucosal immunity – Appears shortly after hatching – Located most prominently in longitudinal folds and fissures of the lower eyelid – Some present in the upper eyelid especially clustered around the opening of nasolacrimal duct – Composed of lymphoid nodules bound by epithelium on one side – Epithelium is comprised of flat cells containing intraepithelial lymphocytes and lack goblet cells

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3.Avian Eye - Pathology a.Introduction It has not received extensive study by veterinarians/pathologists. Reasons:

– Few primary ocular conditions – Lack of knowledge of eye diseases, clinical and pathological – Unique structure of the avian eye, different terminology – Eye size in relation to body size – Extra organ to deal with – Difficult to take out, lengthy processing, needs decalcification of scleral ossicles – Does not explain cause of death or problem – Prone to autolysis

b.Clinical Signs Eye - dullness, hyphema, hypopyon Conjunctiva - reddening, lacrimation, ocular discharge (exudate) Eyelids - swelling, blepharospasm, photophobia (closing) Size of the globe - micro and macro Aqueous flare, corneal opacity/ulcers, cataracts and inflammation Blindness - running in to objects

c.Mydriasis Difficult to achieve because of striated muscles in iris, compounds used include:

– Tubocurarine - injection was effective but not topical (partial) – Vecuronium bromide - topical was effective – Alcuronium chloride - topical was effective but resulted in paralysis – Pancuronium bromide - topical, inconsistent – General anesthetics; ketamine and xylazine, very effective

d.Avian Eye – Fixation and processing Fixatives

– Boun’s solution (Picic acid, glacial acetic acid and formaldehyde) – Alcohol (Absolute alcohol, chloroform, glacial acetic acid) – 10 % neutral buffered formalin, most practical fixative – For better fixation formalin may be injected in to larger eyes – Harden eye in a series of alcohols at concentrations (50 %, 75 % and 95 % for 24 hours each) – Trim the eye to a suitable size and place it in decalcifying (of scleral ossicles) solution for 1 to 2

days depending on the size of the eye and the species of the bird – Trim from posterior (keeping optic nerve in the middle) aspect to the middle of cornea

Processesing and sectioning – Most difficult organ to section, every effort should be made to reduce creation of artefacts – Retinal detachment common

Avian Eye - as models Accommodation Myopia Glaucoma Developmental/Genetics Teratology Disease

GENETIC MODELS Chicken

– Microphthalmia – Retinal dysplasia

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– Keratoconus – Hyperplastic lens epithelium – Coloboma of iris – Cataracts – Ocular anomalies

Japanese quail: – Ring retina – Scleral ectasia – Glaucoma – Cataract

Slate turkey – Secondary angle closure glaucoma

Canary – Cataracts

Pigeon – Microphthalmia

Emu – Mucopolysaccharidosis type IIIB (Sanfilippo B syndrome)

MICROPHTHALMIA Four models

– Barred Plymouth Rocks, autosomal recessive, lethal gene – Brown Leghorns, dominant with incomplete penetrance, failed to survive to maturity – New Hampshire, autosomal recessive – Mutant chickens, autosomal recessive

RETINAL DYSPLASIA Many models:

– Smyth chicken (Delayed Amelonotic - DAM) Used as model for vitiligo and others

– Rods and cones (rc/rd) – Partial dysplasia and degeneration (rdd) – Blindness, enlarged globe( Beg) – Retinopathy (rt) – Retinal dysplasia in B-line(rd-B)

e.Anomalies of the Avian Eye Microphthalmia/anophthalmia Optic nerve hypoplasia/atrophy Corneal edema, corneal and scleral ectasia Cataracts, cystic spaces in lens, aphakia Retinal dysplasias Eyelid malformations Others; scleral ossicles anomaly Albinism CAUSES Genetics Nutrition Toxicity Environment

– Temperature – Humidity – Turning of eggs, position of eggs

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– Oxygen supply – Overcrowding and others

f.Bacterial diseases E. coli Salmonella sp. (S. arizonae, S. typhimurium, S. pullorum) Chlamydophila psittaci Mycobacterium sp. (avium, genavense and tuberculosis) Mycoplasma sp. (MG, MS, etc.) Pasteurella multocida Ornithobacterium rhinotracheale Bordetella avium (turkey coryza) Avibacterium (Haemophilus) paragallinarum (chicken coryza) Riemerella anatipestifer Staphylococcus sp., Streptococcus sp. Pseudomonas aeruginosa Erysipelothrix rhusiopathiae Others: C. botulinum, Gallibacterium anatis. Corynebacterium, Klebsiella, Yersinia, Nocardia, Listeria,

Coxiella sp., etc.

g.Fungal diseases Aspergillosis: A. fumigatus, A. flavus Candidiasis: C. albicans, etc. Ochraconosis (Previously Dactylariosis): D. gallopava Favus: Microsporum gallinae Others: Histoplasma encapsulatum, Cryptococcus neoformans, Malassezia sp. etc.

h.Viral Diseases Pox - pox virus Newcastle disease - Avian paramyxovirus -1 (APMV-1) APMV-3 of psittacines and passerines Psittacine herpesviruses Herpesvirus (cytomegaly) of Finches Polyomavirus of psittacines and passerines Circovirus of pigeons and psittacines Marek’s disease – herpesvirus Retroviruses – J subgroup of ALV, RE virus Duck viral enteritis - herpesvirus Infectious laryngotracheitis - herpesvirus Avian encephalomyelitis - picornavirus Avian influenza - orthomyxovirus Infectious bronchitis - coronavirus Parvoviruses of ducks and geese Papillomavirus Metapneumovirus Adenovirus West Nile Virus Avian Bornavirus (PDD) Reovirus, etc.

i.Parasitic diseases Oxyspirura mansoni (nematode) Philophthalmus gralli (trematode) Toxoplasma gondii

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Leucocytozoon sp. Sarcocystis sp. Cryptosporidia sp. Trichomonads Others: Atoxoplasma-like, Microsproidia, Hemoproteus, Hemosporozoa, Plasmodium sp.

Histoplasmodium, Filaria, Mites, Cyathostoma, Schistosoma, etc. Others (Protista): Rhinosporidiosis: R. Seeberi j.Nutritional diseases Vitamin A deficiency Vitamin E deficiency Pantothenic acid deficiency Biotin deficiency Zinc deficiency Others: Tyrosine

k.Toxicities Ammonia Vitamin A Ionophores Heavy Metals (lead) Spring Parsley and other plants Ammeline Quaternary ammonium Others; Hydrogen peroxide, Sulfur, Kerosene, Warfarin, Creosote, Glycine, etc.

L.Neoplasia Not common Lymphoma (Marek’s disease virus) Sarcoma, J virus Carcinoma Melanoma, retinoblastoma, medulloepithelioma Others; Papilloma, osteosarcoma, etc. Extension of carcinoma of adenohypophysis

m.Trauma n.Diseases of genetic or unknown etiology Microphthalmia/anophthalmia Retinal dysplasia Cockatiel conjunctivitis Lovebird eye disease Mynah bird keratitis Amazon punctate keratitis Cataracts Glaucoma Amyloidosis Gout Eyelid malformations Cryptophthalmia (Atresia of eye lids – bilateral, eyelids reduced in length, but normal in

conformation, lack of palperbral fissures. Most common in cockatiels, members of same clutch, Retinal detachment in Pheasants MPS type IIIB (Sanfilippo B) in Emu’s Amelanotic eye in turkeys and chickens Intraocular ossification (chickens)

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Blepharoconjunctivitis in turkeys Eye-notch syndrome in chickens Cataracts and optic nerve hypoplasia in turkeys Conjunctivitis and uveitis in chickens Others; Synophthalmia, Scleral inclusion cysts, Conjunctival cysts, Corneal dystrophy, Crystalline

deposition in Cornea, etc.

References: 1. Barr BC, Murphy CJ, Ghazakanaian GY, Bellhorn RW. Cataracts and optic nerve hypoplasia in

turkey poults. Avian Dis. 1988;32:469-477. 2. Belluco, S, Chahory S, Vanore M, Wyrzykovsky B, et al. Congenital cataract in 1-day-old French

Mullard ducklings. Avian Path. 2009;38:9-11. 3. Boute C, Hayes S, Young RD, Kamma-Lorger CS, et al. Ultrastructural changes in the retinopathy,

globe enlarged (rge) chick cornea. J Struct Biology. 2009;166:195-204. 4. Chmielewski NT, Render JA, Schwartz LD, Keller WF et al. Cataracts and crooked toes in Brahma

chickens. Avian Dis. 1993;37:1151-1157. 5. Cheville NF, Tappe J, Ackermann M, Jensen A. Acute fibrinopurulent blepharitis and conjunctivitis

associated with Staphylococcus hyicus, E. coli and Streptococcus sp. in chickens and turkeys. Vet Pathol. 1988:25:369-375.

6. Cortes PL, Tiwary AK, Puschner B, Crespo RM. et al, Vitamin A deficiency in turkey poults. J Vet Diagnostic Invest. 2006;18:489-494.

7. Evans WM, Bruner DW and Peckham MC. Blindness in chicks associated with salmonellosis. Cornell Vet. 1955;45:239-247.

8. Ghew M. Megaloschizonts of leucocytozoon in the eyes and sciatic nerves of the domestic fowl. Vet Rec. 1968;83:518-519.

9. Hepding L. About toxoplasma (Toxoplasma gallinarum n sp.) in the retina of a hen and its relationship to Marek’s disease. Infekt Krankh Haust. 1939;55-109-118.

10. Kennedy FS. An outbreak of conjunctival Rhinosporidiosis in swans, Cygnus spp. Proc. Assoc. Av Vets. 1994;426-427.

11. Korbel RT. Avian Ophthalmology – A clinically-oriented approach. Proc Annu Conf Assoc Avian Vet. 1999;335-350.

12. Landman W, Boeve MH, Dwars RM, Gruys E. Keratoglobus lesions in the eyes of broiler breedes. Avian Path. 1998;27:256-262.

13. Lauber JK. Review: light-indcuedavain glaucoma as an animal model for human primary glaucoma. J Ocul Pharm. 1987;3:77-100.

14. Martin GR. Eye. In, King AS & McLelland J (ed). Form and Function in Birds. Academic Press, Vol 3,1985;311-375.

15. Nakamura K. Abe F. ocular lesions in chickens inoculated with E. coli. Can J Vet Res. 1987;51:528-530.

16. Nckel R, Schummer A & Seiferle E. Organ of Vision (organum visus). In, Anatomy of the Domestic Birds. New York;Springer-Verlag, 1977;148-155.

17. Nunoya T, Yagihashi T, Tajima M, Nagasawa Y. occurrence of keratoconjunctivitis apparently caused by Mycoplasma gallisepticum in layer chickens. Vet Pathol. 1995:32:11-18.

18. Olson LD. Ophthalmia in turkeys infected with Pasteurella multocida. Avian Dis. 1981;24:423-430. 19. Pandiri AK, Cortes AL, Lee LE and Gimeno IM. Marek’s disease virus infection in the eye:

chronological study of the lesions, virus replication, and vaccine-induced protection. Avian Dis. 2008;52:572-580.

20. Raggi LG, Armstrong WH. Conjunctivitis of chickens caused by a typical infectious laryngotracheitis virus. Avian Dis. 1960;4:272-274.

21. Randall CJ. Conjunctivitis associated with cryptosporidial infection. Vet Rec. 1986;118:211. 22. Rymer J, Choh V, Bharadwaj S, Pamanabhan V, et al. The albino chick as a model for studying

ocular development anomalies, including refractive errors, associated with albinism. Exp Eye Res. 2007;85:431-432.

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23. Shivaprasad HL. Poultry Ophthalmology. In, Gelatt KN (ed). Veterinary Ophthalmology. 3rd ed. Baltimore: Lippincott, Williams and Wilkins. 1999;1177-1207.

24. Shivaprasad HL, Korbel R. Blindness due to retinal dysplasia in broiler chicks. Avian Diseases. 2003;47:469-473.

25. Shivaprasad, HL. Eye and Ear. Avian Histopathology. Ed by Oscar Fletcher. 3rd Edition,Pp, 292-323. American Association of Avian Pathologists, Jacksonville, FL.

26. Smith TW, Albert DM, Robinson N, Calnek BW et al. Ocular manifestation of Marek’s disease. Invest Ophthalmol. 1974:13:586-592.

27. Smyth JR Jr., The Smyth chicken: a model for autoimmune amelanosis. Crit Rev Poult Biol. 1989;2:1-19.

28. Sola SC, Castagnaro M, Cheng KM. Histological changes caused by the rc mutation in chickens. J Comp Path. 1997;116:329-338.

29. Silva EN, Hipolito O, Grecchi H. natural and experimental salmonella arizona 18:z4;z32 (Ar:7:1,7,8) infection in broilers. Bacteriological and histopathological survey of eye and brain lesions. Avian Dis. 1980;24:631-636.

30. Ulshafer RJ. Avian models of hereditary retinal degeneration. In: Retinal degeneration: experimental and clinical studies. NY, NY. Alan R. Liss. 1985:321-337.

31. Willis AM & Wilkie DA. Avian Ophthalmology Part 2: Review of Ophthalmic Diseases. J Avian Med Surg. 1999;13;245-251.

32. Wright GW, Frank JF. Ocular lesions in chickens caused by ammonia fumes. Can J Com Med. 1957:21”225-227.

Bird Ear: anatomy and diseases:

1. Avian hearing characteristics a. Hearing after vision, second most important sense in birds b. Warning, social and detecting prey c. Songbirds have the most complex auditory communication signals d. Hunting owl has the best acuity in acoustically locating a target in three-dimensional

space

2. Avian Ear. Not well studied because; a. Difficult to access (except external ear) b. Does not explain cause of clinical signs (except neurological) or death c. Complex anatomy of the inner ear d. Difficult to trim and process, needs decalcification e. Extra organ to deal with f. Diseases not well known or described

3. Avian Ear – used as a model to study

a. Effect of sound/noise on ears b. Ototoxicity c. Hair cell regeneration d. Genetic conditions

4. Anatomy: External, Middle and Internal Ears

External Ear: a. No external sound-collecting structures (aerodynamically disadvantageous) b. Openings located ventral and caudal to eye

exception woodcock and snipe (ventral to eye) c. Openings asymmetrical in nocturnal birds d. Ear opening covered by auricular feathers

exception Casuariformes, some vultures and ibises e. Short canal extending vertically and caudally from external acoustic meatus to tympanic

membrane

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acoustic meatus very large in owls, communicates with air spaces f. In diving birds very narrow and can be closed g. Lined with epidermis and contains glands that secrete waxy material

number of glands, up to 25? h. Lymphoid tissue, normal (External Ear Assoc. Lymphoid Tissue – EEALT?) i. Tympanic membrane:

separates the external from middle ear, convex in birds

external surface epidermis, internal surface epithelium Middle Ear:

a. Air filled funnel-shaped cavity between tympanic membrane and inner ear – connects to oropharynx via Eustachian (auditory) tube – communicates with air cavities – communicates with left and right tympanic cavities via air sinuses (esp. in owls) – lined by cuboidal epithelium

b. Contains single rod-like ossicle called columella (similar to stapes in mammals) – extends across tympanic cavity – forms direct connection between tympanic membrane and perilymph of inner ear – is composed of bone and cartilage (similar to stapes in mammals) – rod-like body terminates in a flat oval base in the vestibular window – Paratympanic organ also present (contains hair cells, may act as a baroceptor)

Inner Ear:

a. Composed of Bony and Membranous labyrinths, and Vestibular and Cochlear organs b. Bony labyrinth is formed by spongy bone

– cavity of bony labyrinth encloses membranous labyrinth c. Membranous labyrinth:

– surrounded by perilymph and contains endolymph – contains semicircular canals, utriculus, sacculus – contains sensory areas of thickened epithelium; maculae, crests, papillae

d. Vestibular organ - equilibrium – system of receptors sensitive to head movements – Includes utriculus, sacculus and lagena

e. Cochlear organ - hearing – short and slightly curved, larger in owls – cochlear duct filled with endolymph – contains sensory epithelium (basilar papilla) – basilar papilla consists of ciliated hair cells and supporting cells

5. Causes of Ear Problems in Birds: Most neglected area and organ

a. Infectious – Bacteria, viruses, fungi, parasites

b. Noninfectious – Genetics, sound/noise, nutritional, toxic, trauma, plant material, tumors

c. Hemorrhage d. Failure to open external auditory meatus

6. Clinical Manifestations of Ear Problems in Birds a. Can vary from none to severe b. Primarily neurological – middle and inner ear infections

c. Discharge from external ear d. Anorexia, ill thrift, loss of weight, weakness, etc.

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7. Diagnosis: a. Clinicians: can use endoscope/otoscope to examine the external ears.

Dr. H. Wilson diagnosed bacterial otitis externa in 7/229 neonatal macaws by use of otoscope which were other wise not suspected (2000 AAV proceedings). Difficult to diagnose otitis media and otitis interna.

b. Pathologists: cut across the lower bone coronal keeping external ears just in front, requires decalcification and proper trimming and sectioning, difficult to section the external, middle and inner ears on the same plane. Occasionally one can section brain along with the ears to see extension of inflammation of the meninges to the vestibulocochlear nerve and inner ear. Anatomy of inner ear is complex and all parts may not be present in the same section and will require step cutting.

8. Specific causes of otitis in birds

Infectious- Bacteria E. coli, Pseudomonas sp.

P. multocida, Riemerella anatipestifer Salmonella sp. (S. arizonae) Staphylococcus/ Streptococcus Mycoplasma sp., Klebsiella sp. Mycobacteria sp., Chlamydophila Enterococcus sp. Proteus mirabilis, Chlamydophila psittaci Others. Infectious – Viruses Avian Paramyxoviruses (1 and 3).

APMV-1 in pigeon’s otitis interna can be the only lesion APMV-3 in passerines and psittacines

Marek’s disease (Herpesvirus) Polyomavirus (otitis interna) Psittacine Herpesvirus Pigeon Herpesvirus Poxvirus (otitis externa and otitis media) Avian Encephalomyelitis – Picorna virus Proventricular Dilatation Disease – Avian Bornavirus Others Infectious - others Fungi: Candida Trichophyton gallinae (Favus) Others Parasites Cryptosporidia

Mites Protocalliphora avium (Diptera) in the external ear canals of raptors Other fly larvae

Others Non Infectious Diseases Anomalies (Failure to open – external ears)

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Nutritional - Vitamin A deficiency (Squamous metaplasia of glands in external ear), others? Toxicities: Aspirin, Retinoic acid, aminoglycosides, Enrofloxacin Tumors – rare. Hemorrhage – middle ear. Real or agonal? Plant material – very common in external ear, can carry bacteria and debris. Photosensitization (Parsley induced) in ostriches Trauma Xanthoma – common in cranial (bone) air spaces Genetics (Basilar papillary dysplasia in Belgian Water Slager canaries, audiogenic and photogenic reflex epilepsy in Fayoumi chickens) Others

9. Otitis Externa: is very common a. External ear continuous with the skin externally

i. Prone to entry by various infectious and non infectious agents through the external opening.

ii. Changes such as acanthosis, hyperkeratosis, epidermitis/dermatitis, ulcers, etc. are common

iii. Glands can go hyperplasia/hypoplasia, vacuolation, squamous metaplasia (vitamin A deficiency), etc.

iv. Bacterial diseases are most common but pox virus (chickens), herpesvirus (pigeons/doves), fungi, mites, larvae of flies can gain entrance.

10. Otitis Media: is common a. Middle ear infection can extend from the Eustachian tube or from the external ear.

Extension from inner ear (otitis externa) is very rare. i. Inflammation of the air spaces of the surrounding bone is also common

ii. Otitis media due to Pasteurella multocida (also called cranial form of fowl cholera) is common in turkeys and chickens.

iii. Other bacteria can also gain entrance through oropharynx. iv. Poxvirus (Canaries) and herpesvirus (psittacines) have also been observed. v. Hemorrhage common but difficult to determine if real or agonal?

vi. Xanthoma of the air spaces (bone marrow-cranium) common.

11. Otitis interna: not uncommon. a. Inflammation of the brain can extend in to the inner ear through the VIIIth cranial nerve. b. Extension from middle ear is rare. c. Other modes; septicemia or viremia

i. Otitis interna due to APMV-1 in pigeons and due to APMV-3 in psittacines and passerines is common.

ii. Bacterial infections such as due to S. arizonae in turkey poults are common. iii. Other viruses and bacteria can also cause otitis interna iv. Ganglionitis of the vestibulocochlear ganglia is common due to various viral

diseases.

References: 1. Choo D, Sanne JL, Wu DK. The differential sensitivities of inner ear structures to retinoic acid

during development. Dev Biol. 1998;204:136-150. 2. Droual R, Woolcock PR. Swollen head syndrome associated with E. coli and infectious bronchitis

virus in the Central Valley of California. Avian Pathol. 1994;23:733-742. 3. Hodges, RD. The Histology of the Fowl. London:Academic Press;1974. 4. Ingram DR, Ross JR, Hagdorn TK. A broiler breeder flock ear infestation with the analgesid mite,

Megninia ginglymura. Poult Sci. 1991;73:141.

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5. Kühne R, Lewis B. External and Middle Ears. In: King AS and McLelland J, eds. Form and Function in Birds. Vol 3. New York: Academic Press;1985:227-271.

6. Lambert PR, Palmer PE, Rubel EW. The interaction of noise and aspirin in the chick basilar papilla. Arch Otolaryngol Head Neck Surg. 1986:112;1043-1049.

7. Matsui JI, Ryals, BM. Hair cell regeneration: An exciting phenomenon…But will restoring hearing and balance be possible? J Rehab Res Develop. 2005;42:187-198.

8. Munger LL, Pledger T. Pseudomonas infection of the middle ear. Proc Annu Conf Assoc Avian Vet. 1993;254-255.

9. Necker R. The Avian ear and hearing. In: Whittow GC, ed. Sturkie’s Avian Physiology. 5th ed. San Diego, CA: Academic Press; 2000:21-35.

10. Nickel R, Schummer A, Seiferle E. Sensory organs (organa sensuum). In: Anatomy of the domestic birds. New York: Springer-Verlag. 1977:140-148.

11. Olson LD. Gross and microscopic lesions of middle and inner ear infections in swine. Am J Vet Res. 1981; 42:1433-1440.

12. Olson, LD, McCune EL. Experimental production of the cranial form of fowl cholera in turkeys. Am J Vet Res. 1968;29:1665-1673.

13. Perelman B, Kuttin ES. Parsley-induced photosensitivity in ostriches and ducks. Avian Pathol. 1988;17:183-192.

14. Randall CJ, Reece RL. Color Atlas of Avian Histopathology. London, UK: Mosby-Wolfe; 1996:219-221.

15. Render J, Fikes J. Gentamicin-induced vestibular toxicosis in newly hatched chicks. Vet Pathol. 1994:

16. Schmidt RE, Reavill DR, Phalen DN. Pathology of Pet and Aviary Birds. Ames, IA: Iowa State Press; 2003:208-209.

17. Shivaprasad HL. Diseases of the nervous system in pet birds; a review and report of diseases rarely documented. Proc Annu Conf Assoc Avian Vet. 1993:213-222.

18. Shivaprasad HL, Cortes P, Crespo R. Otitis interna (labyrinthitis) associated with Salmonella enterica arizonae in turkey poults. Avian Dis. 2006;50:135-138.

19. Shivaprasad, H. L. Eye and Ear. Avian Histopathology. Ed by Oscar Fletcher. 3rd Edition, 20. Pp, 292-323. American Association of Avian Pathologists, Jacksonville, FL. 21. Wilson H, Graham JE, Ritchie B. Otitis externa in a group of neonatal psittacine birds. Proc Annu

Conf Assoc Avian Vet. 2000:197-198.

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Diseases/etiologies of the Musculoskeletal System in Poultry - An Outline

Anomalies:

1. Scoliosis 2. Valgus/Varus 3. Spondylolistheses (“kinky back”) 4. Rumplesness 5. Cleft strernum/Sternoschisis 6. Syndactlylia, Polydactylia, Phocomelia, etc. 7. Brachygnathia 8. Spina bifida 9. Achondroplasia 10. Torticollis (wry neck) 11. Crooked toes 12. Tibial rotation 13. Dwarfism 14. Others

Metabolic:

1. Inherited muscular dystrophies (UC Davis 300 and others) 2. Focal myopathy in turkeys 3. Inherited muscle diseases in Japanese quail (Type II glycogenosis, myotonic muscular dystrophy). 4. Arthrogryposis 5. Dwarfism (sex-linked) and autosomal (?) 6. Others

Viruses and Viral Diseases:

1. Marek’s disease (lymphoid tumors) 2. Retrovirus (Osteopetrosis, Sarcoma. Myelocytoma/myelobastosis, etc.) 3. Avian Paramyxovirus -1 (END/NDV) 4. Orthomyxovirus (HPAI) 5. Muscovy duck parvovirus (ducks, geese) 6. Infectious bursal disease virus 7. Chicken infectious anemia virus 8. EEE, Highland J (turkeys experimental) 9. Others

Bacteria and Bacterial Diseases:

1. Arthritis/synovitis, osteomyelitis (Salmonella sp., E. coli, P. multocida, Mycoplasmosis, Staphylococcus aureus, S. hyicus, Streptococcosis/Enterococcus sp. (E. cecorum), Mycobacteriosis, Listeria, etc,

2. Gangrenous Myositis - C. septicum, C.perfringens, S. aureus, etc. 3. Amyloid arthropathy (Enterococcus faecalis, MG, MS, Salmonella sp. S. aureus, E. coli, etc.) 4. Yersinia pseudotuberculosis 5. Erysipelothrix rhusiopathiae 6. Pseudomonas aeruginosa 7. Others

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Mycotic Diseases: 1. Aspergillus sp. 2. Candida sp.

Parasitic Diseases: (Myositis)

1. Sarcocystis sp. 2. Leucocytozoonosis. 3. Haemoprotozoa 4. Toxoplasmosis 5. Others

Nutrition:

1. Vitamin E/Selenium (myopathy) 2. Rickets (Ca, P, Vit D3 def or imbalance of Ca:P ratio) 3. Osteoporosis/osteomalacia 4. Hypovitaminosis A (thickening of skull bones) 5. Biotin, choline, manganese, pantothenic acid, niacin (perosis) 6. Manganese/choline deficiency (Slipped tendon) 7. Copper (brittle bones – similar to TD) 8. Electrolytes (TD?) 9. Protein def (Muscle atrophy) 10. Zinc (leg deformities in pheasants) 11. Others

Neoplasia:

1. Lymphoma of virus induced (Marek’s, LL, REV, etc.) 2. Rhabdomyoma/sarcoma 3. Osteoma/sarcoma 4. Chondroma/sarcoma 5. Fibroma/sarcoms 6. Myxosarcoma 7. Metastatic adenocarcinoma/sarcoma 8. Hemangiosarcoma 9. Others

Toxicity:

1. Ionophores (Monensin, Lasalocid, Salinomycin, Narsin, etc.) 2. Cassia occidentalis (Coffee senna) 3. Hypervitaminosis A (intereference with Vit. D3) 4. Vitamin D (soft tissue mineralization - proventriculus) 5. Selenium (beak deformity) 6. Others

Others:

1. Tibial Dyschondroplasia 2. Deep pectoral myopathy 3. Gout (both articular and visceral urate deposition forms) 4. Femoral head necrosis 5. Avulsion of ligaments and tendons 6. Rupture of gastrocnemius tendon 7. Femoral fractures and other bones 8. Degenerative joint diseases 9. Osteochondrosis 10. TS-65 (chondrodystrophy)

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14. Spraddle-leg 15. Ossification of tendons and cartilage 16. Bumblefoot 17. Vaccine induced myositis/osteomyelitis 18. Improper toe clipping 19. Dehydration 20. Steatosis 21. Rhabdomyolysis (capture, transport, etc.) 22. Pipping muscle degeneration 23. Myodegeneration of Anterior Latissimus Dorsi in broiler chickens 24. White striping (Pale streaks in broiler meat)) 25. Muscles tears, hemorrhages 26. Xanthoma (common in bone marrow) 27. Trauma 28. Others

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Diseases or etiologies of the Endocrine System in Poultry - An Outline

Not well studied nor examined routinely in poultry; thyroids, adrenals, islets in pancreas, pituitary, pineal Anomalies:

1. Dystophic thyroid glands 2. Pancreas atrophy 3. Others:

Metabolic:

1. Autoimmune thyroiditis – Obese strain of chicken used as a model, (Lymphocytic thyroiditis in Fayoumi breed of chicken)

2. Goiter in Brahma chickens - genetics 3. Diabetes – experimental work in chickens 4. Amylodosis. 5. Others:

Virus and viral diseases:

1. Marek’s disease (lymphoid tumors) 2. Retroviruses (LL; inclusion bodies, REV, Myelocytoma) 3. Avian Paramyxovirus -1 (END) 4. Orthomyxovirus (HPAI) 5. WNV in ducks and geese 6. Alphaviruses (WEE, EEE, Highland J) 7. Others

Bacteria and bacterial diseases:

1. Salmonellosis (S.pullorum/S.gallinarum, S. typhimurium, S. enteritidis, etc.) 2. Colibacillosis 3. P. multocida 4. Chlamydiosis 5. Erysipelothrix rhusiopathiae 6. Mycobacteriosis 7. Others

Mycosis:

1. Aspergillosis

Parasites: 1. Toxoplasmosis 2. Others

Nutritional: 1. Calcium, phosphorus and vitamin D3 deficiency or imbalance of Ca to P ration -

hyperparathyroidism 2. Others

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Neoplasia:

1. Virus induced neoplasia 2. Adenoma/carcinoma - rare 3. Others

Toxicity:

1. Rapeseed, Iodine, Propylthiouracil, Sulofonamides – thyriod affected 2. Others

Others:

1. Corpora amylacea in thyroids (mineralized follicles, hemosiderosis, etc) 2. Adrenocortical hyperplasia or vacuolations – stress induced 3. Pigments in adrenals (bile, hemosiderin, lipofuscin, mineralization, urates, etc.) 4. Cysts 5. Others:

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Diseases or etiologies of the Urogenital Systems in Poultry - An Outline

Anomalies:

1. Renal aplasia/hypoplasia, dysplasia 2. Renal cysts. 3. Cystic right oviduct, two functional oviducts 4. Ovarian/oviductal cysts, ovarian hypoplasia 5. Misovulation- ovum deposited in body cavity 6. Internal/abdominal laying 7. Testicular hypoplasia (WLH, turkey) 8. Testicular degeneration/atrophy – Japanese quail (with Muscular dystrophy) 9. Hermaphrodite/intersex 10. Others:

Metabolic:

1. Perirenal hemorrhage (turkey) 2. Hemochromatosis 3. Fatty liver and kidney syndrome 4. Amyloidosis. 5. Articular urate deposition (Gout) 6. Urolithiasis 7. Atherosclerosis 8. Others

Virus and viral diseases:

1. Marek’s disease (lymphoid tumors) 2. Retroviruses (LL; inclusion bodies, REV, Myelocytoma) 3. Infectious bronchitis virus (IBV) 4. Avian Nephritis virus (Astrovirus) 5. Avian Paramyxovirus -1 (END/NDV) and 3. 6. Orthomyxovirus (HPAI) 7. Adenovirus group II (HEV with IN inclusions in turkeys) 8. Egg Drop Syndrome (EDS 76 in chickens) – Duck adenovirus 9. Avian Encephalomyelitis virus (Picornavirus) 10. Avian Metapneumovirus (TRT in turkeys) 11. Hepatitis E virus in chickens 12. Flavivirus (WNV in ducks and geese) 13. Alphaviruses (WEE, EEE, Highland J) 14. Others

Bacteria and bacterial diseases:

1. Salmonellosis (S.pullorum/S.gallinarum, S. typhimurium, S. enteritidis, etc.) 2. Colibacillosis 3. Staphylococcosis 4. Pasteurellosis (P. multocida, P. gallinarum) 5. Riemerella anatipestifer 6. Ornithobacterium rhinotracheale

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7. Mycoplasmosis 8. Erysipelothrix rhusiopathiae 9. Mycobacteriosis 10. Streptococcosis 11. Enterocccus sp. 12. Others

Mycosis:

1. Aspergillosis 2. Zygomyces 3. Candida sp. (geese) 4. Others.

Parasites: 1. Renal coccidia (geese and ducks) 2. Toxoplasmosis 3. Cryptosporidiosis 4. Leucocytozoonosis 5. Sarcocystosis 6. Hemoprotozoa 7. Cestodiasis (waterfowl) 8. Aberrant ascarids (oviduct) 9. Trematodes/Schistosoma of billharzia sp. (waterfowl), Prosthogonimus machorchis. 10. Ciliates (oviduct – waterfowl)

Nutritional: 1. Ca, P and Vitamin D3 deficiency (Egg shell quality) 2. Vitamin A def (Squamous metaplasia) 3. Biotin def (Fatty liver and kidney syndrome, fatty change in myocardium) 4. Vitamin E/Selenium 5. Others

Neoplasia:

1. Virus induced neoplasia (lymphoma and others) 2. Renal tumors (embryonal nephroma, tubular adenoma, adenocarcinoma) 3. Ovarian carcinoma (chicken used as a model) 4. Oviductal carcinoma 5. Leiomyoma of mesosalpinx 6. Granulosa cell tumor 7. Arrhenoblastoma, dysgerminoma, luteoma, thecoma 8. Ssarcoma’s (fibrosarcoma, others) 9. Hemangioma/sarcoma 10. Metastatic adenocarcinoma (rare) 11. Mixed tumors, Met Melanoma 12. Teratoma of testes 13. Sertoli cell tumor, Seminoma, Leydig cell tumor 14. Others

Toxicity:

1. Heavy metals (lead, zinc, cadmium, arsenic) 2. Antibiotics (Gentamycin, amikacin, tetracyclines, sulfonamides, etc.) 3. Sodium (cystic testes, hydropericardium, ascites) 4. Mycotoxins (Citrinin, ochratoxin, oosporein, aflatoxins, etc.) 5. Furazolidone, mercury

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6. Diclofenac (NSAID) 7. Sodium carbonate/citrate/calcium carbonate 8. Plants (Oak, etc.) 9. Hypervitominosis D3 (nephrocalcinosis) 10. Toxic fat syndrome (dioxins, PCB’s) 11. Excess protein 12. Others

Others:

1. Dehydration 2. Visceral urate deposition (Gout) 3. Phallus/oviductal prolapse 4. Egg bound condition 5. Chronic renal disease 6. Others:

Table 1: Differences between Visceral and Articular urate deposition (Gout) in Birds

Visceral gout (Visceral urate deposition)

Articular gout (urate deposition)

1. Onset:

It is usually an acute condition but can be chronic.

It is usually a chronic disease.

2. Frequency:

It is very common.

It is rare or sporadic.

3. Age:

1 day and above.

4-5 months and above. However, immature genetically susceptible chickens may be induced by high protein levels in the diet.

4. Sex:

Both males and females are susceptible.

Mostly males.

5. Gross lesions

Kidney:

Kidneys are almost always involved and they look grossly abnormal with deposition of white, chalky precipitates.

Kidneys are normal grossly. Kidneys may become abnormal with white urate deposits if the bird gets dehydrated.

Soft tissues:

Visceral organs like liver, myocardium, spleen or serosal surfaces like pleura, pericardium, air sacs, mesentery, etc. are commonly involved.

Soft tissues other than synovium are rarely involved, however, comb, wattles, and trachea have been observed to be involved.

Joints:

Soft tissues around the joints may or may not be involved. Surfaces of muscles, synovial sheaths of tendons and joints are involved in severe cases.

Soft tissues around the joints are always involved, especially feet. Other joints of the legs, wing, spine, and mandible are also commonly involved.

6. Microscopic

lesions:

Generally no inflammatory reaction in synovium or visceral surfaces. Kidney has inflammatory reaction around tophus.

Granulomatous inflammation in synovium and other tissues.

7. Pathogenesis:

It is generally due to failure of urate excretion (renal failure).

It is probably due to a metabolic defect in the secretion of urates by the kidney tubules.

8. Causes:

1. Dehydration.

a. Genetics.

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2. Nephrotoxicity: calcium, mycotoxins, (ochratoxins, oosporein, aflatoxins, etc.), certain antibiotics, heavy metals (lead), ethylene glycol, ethoxyquin etc. 3. Infectious agents: nephrotropic IBV and avian nephritis virus (chickens), polyomavirus, APMV-1 (pigeons), Salmonella sp., Yersinia sp., Chlamydia psittaci, Eimeria truncata, microsporidia, cryptosporidia, Aspergillus sp., etc. 4. Vitamin A deficiency 5. Urolithiasis 6. Neoplasia (lymphoma, primary renal tumors) 8. Immune mediated glomerulonephritis 9. Anomalies 10. Others?

b. High protein in the diet. c. Others?

Ref: Shivaprasad, H. L. An overview of anatomy, physiology and pathology of urinary system in birds, AAV Proceedings, pp. 201-205, 1998