avian reo virus
TRANSCRIPT
Avian Reovirus
Dr. Naeem TahirAssistant Manager Sales Jadeed Farms (Pvt) ltd.Faisalabad
Introduction In 1957, Olson and his coworkers determined that the synovitis agent was a virus, which they called “viral arthritis agent.” The virus was subsequently identified by Walker as a reovirus by electron microscopy. Soon other isolations of reovirus were reported from various places in the United States and all around the world.
Cases of Reovirus tenosynovitis have been reported throughout the UK in a number of integrations this year.
Cases of Reovirus tenosynovitis have been reported throughout Europe and
United States of America and many other Asian and African countries throughout the last year.
Occurrence
Virus isolation Aseptically extracted tendon
tissue from broilers Virus isolation conducted by
AHVLA Weybridge 3 Passages Reovirus isolated
FROM TENODON TISSUE
Histology Tendons, joint capsule and tendon
sheath- mixed inflammatory infiltrate- both heterophilic and lymphoplasmacytic.
NOT POSSIBLE TO DETERMINE WHETHER BACTERIAL OR VIRAL FROM HISTOLOGY ALONE.
General Characteristics Birds reported lame “walking on their hocks using wings to balance”.
Acute onset at 13-14 days of age.
Poor uniformity
Poor growth rates
Bursa of Fabricius and thymus gland are atrophied.
Femoral head disintegration on disarticulation of the coxofemoral joint.
Thickening of the growth plates of long bones.
Arthritis and osteoporosis.
Transmission Through infected and carrier birds Poultry products, offal's from infected birds Mechanical vectors Wild birds Faulty vaccination Contaminated feed and water Vertical route of transmission is also proved
Thymus cortex is thinner and difficult to be differentiated from medulla.
Atrophy of follicles of Bursa of Fabricius.
Bones abnormality in the femur growth plate with necrosis of cartilage.
Proventriculitis with focal necrosis and infiltration of Inter glandular tissue with mononuclear cells.
Histopathological lesions
Distended abdomen Increased fluid in tendons of hocks Concurrent mild pericarditis/epicarditis Enlarged proventriculus Shrinkin pancreas Intestine containing undigested orange feed
Postmortem examination
Differential diagnosis
Primarily considered likely infectious agent given inflammation and effusion of tendonMycoplasma Synoviae
Staphylococcus Tenosynovitis/ Arthritis
Enterococcus Tenosynovitis/Arthritis
Airsacculitis
Inflammation of joints
Ruffle feather
Distended abdomen
Shrinkin pancreas
Reovirus Nil Yes Yes yes Yes
Mycoplasma Synoviae
Yes In some cases
Yes Nil Nil
Staphylococcus Tenosynovitis/ Arthritis
Nil Yes Yes Nil Nil
Enterococcus Tenosynovitis/Arthritis
Nil Yes Yes Nil Nil
1- Staphylococcus Tenosynovitis / Arthritis Swabs taken from hocks, tendons and pericardial tissuesResults – no growth after 48 hoursBirds swabbed not being treated with antibiotics and investigation undertaken at early stage of infection
NOT STAPHYLOCOCCUS OR ENTEROCOCCUS TENOSYNOVITIS/ARTHRITIS
Course of investigation
2- Mycoplasma SynoviaeSerology:Rapid serum agglutination on sera of 20 birds showing symptoms in affected flock- taken at time of site visitResults- negativeHowever- serology relies on antibody production- acute vs convalescent phase of infection- could not rule out on the basis of this test alone
Then……..8-12% mortality due to cullingNo response to antibiotic treatment either
antimycoplasmal or amoxycillinWelfare concerns due to lameness Poor conversion 1.80+ vs 1.62Poor uniformitySome response to aspirin treatment-
– better mobility, lower culling rates
Questions! Why have so many companies and countries suddenly reported this syndrome?
Why have some flocks which have not been derived from the known positive PS also developed symptoms?- cross infection in hatchery?
Why did some flocks from the same parent flock not show symptoms?- age related resistance?
Is this a new strain of Reovirus or is it a previously recognised strain?- Reoviruses appear to be continuously involving.
What methods are being used to type Reovirus and are these consistent throughout laboratories?- there is no consistency at this time.
Will double Reo inactive vaccination confirms protection?
• Biosecurity• Hatching egg hygiene• Hatchery hygiene• Vaccination- double vaccination
strategy advised in outbreak areas• Sigma B antibodies• Autogenous vaccination
Prevention and Control
General appearance of the effected bird
Swelling of hock joint
Diagrams of Post mortem Lesions of Avian Reovirus
Enlarged Proventiculus
Distended abdomen
Tissue fibrosis in the affected area
Tendon sheaths contain a small amount of straw-yellow exudates
Intestine containing undigested orange
feed
Catarrhal enteritis with white color and Dilated
intestine.
Shrinkin pancreas in affected broiler
Shrinkin pancreas in affected broiler
Small intestine is pale, dilated and contain indigested forage
Small intestine is pale and dilated
Thank you