Download - Sarcoptic Mange

Sarcoptic Mange• Sarcoptes scabiei mite• ~1/64 of an inch long • Pearly white and oval-shaped • Spines on bodies• Year-round; winter• Humans ("scabies"), canids, felids,

bears, mustelids • Common in red fox, wolves, and

coyotes in N. America• impacts on younger animals • Highly contagious, direct transfer of

mites at any stage of their development

• Indirect transfer of mites (mechanical transfer) – importance?

Sarcoptic Mange• Highly specific to host type, • Life cycle completed in

burrows within epidermis of host

• Adult mites mate in small pockets near the surface of skin

• Hatched larvae pass through a nymphal stage and continue migration through epidermis, becoming adults within 2 weeks

Sarcoptic Mange• Female mites burrow into skin of

host; use jaws and front legs to cut skin

• Female lays 2-3 eggs each day, up to 2 months

• Larvae hatch, 3-4 days • Crawl onto surface of skin, use hair

as shelter• Both larvae and adults eat skin cells

from hosts

Sarcoptic Mange• Oily skin, crusting, hair loss, scab

formation • Lesions - physical damage to skin,

irritation caused by parasite excretions, and allergic response of host

• Hair loss in characteristic patterns (alopecia)

• Poor body condition, listlessness, abnormal behavior, increased scavenging

• May ultimately die from complications with mange infection or exposure; winter

Sarcoptic Mange

• Trichodectes canis• Dog biting louse • 2ndary infection

Sarcoptic Mange – WI Wolves• 1st identified in a Great Lakes

wolf, 1991• Since 1991, signs of mange

detected in 27% of wolves • High of 58% in 1992-1993 • 1993 = 11% decline in wolf

population • Some literature suggesting

population impact most severe in 2nd or 3rd year of epidemic

• Impacts on annual pup survival?

Ticks

• Ixodes (e.g., deer tick; Lyme disease (Borrelia burgdorferi)

• Dermacentor (Am. Dog tick & Rocky Mtn wood tick); Rocky Mountain spotted fever (Rickettsia rickettsii )

• Amblyomma (e.g., lone star tick; Ehrlichiosis (Ehrlichia)

Ticks

Winter tick (Dermacentor albipictus)

Ticks• Moose begin grooming in Jan (nymph stage) – mechanical and/or immunological irritation• Extensive grooming through Mar-Apr = destroy winter coat • Severe hair loss = gray coloration (undercoat) = "ghost moose".

Nasal Leeches• Leech (Genus Theromyzon) feeds

directly on blood from nasal passages, trachea and mucous membranes of eyes

• Spring/summer - leeches actively seeking potential hosts and reproducing

• Dabbling ducks (e.g., mallard, teal, wigeon, northern shoveler, etc.) and swans

Nasal Leeches• Protruding from nares or

attached externally• Resemble small sacks of blood• Birds vigorously shaking

heads, scratching bills or sneezing

• Nasal and respiratory tract infestations = labored breathing and gaping (similar to aspergillosis infection)

Nematodes = roundworms

Complete digestive systems

Most species dioecious

2 main categories

eggs are infective

larva are infective

Gizzard Worm

• Parasitic nematode• Genus Amidostomum

or Epomidiostomum• 10-35 mm, coiled,

thread-like roundworm• Beneath surface lining

and grinding pads of gizzard

• waterfowl

Gizzard Worm

Gizzard Worm

• 1st exposure on breeding grounds

• Large worm burdens; reduce vigor, couple with migration, etc…

• No field signs• Poor growth/weight gain

in young birds?• Emaciation, general

weakness• Poor digestion

Raccoon roundworm - Baylisascaris procyonis


Definitive host

Life cycle is direct or indirect depending on age of raccoon


Adults in intestines lay eggs


Eggs are shed with feces


Eggs are shed with feces – loads of ‘em


Sticky, proteinaceous outer coat


Over 2-4 weeks the eggs develop larvae


Can remain infectious for years


Embryonated egg with larvae is ingested by young raccoon -- Direct


Egg hatches in to larva


Larvae in intestines develop into egg-laying adults

Infection rates in raccoons are high – as high as 70% of adults and over 90% of juveniles


Embryonated egg with larvae are ingested by intermediate hosts


Eggs hatch and release larvae into intestines gut wall migrate thru the various tissue (larval migrans) causing considerable damage and then encyst


In the eye blindness


5-7% CNS disease


Dead intermediate is scavenged by adult raccoon – Indirect

Raccoons are ubiquitous in U.S. and urban adapted

http://www.maniacworld.com/raccoon-encounter-with-dog-and-cat.html


http://www.maniacworld.com/raccoon-encounter-with-dog-and-cat.html


Definitive host??

http://www.funny-clip-art-cool-drawings.com/dog-sketches.html

An emerging zoonotic especially of young children

•Contact with raccoon feces

•Pica/geophagia

•Young age (less than 4)

•Male

•Developmental delay

•At any age – anyone exposed to raccoon feces – researchers, wildlife rehabilitators, etc – asymptomatic or subclinical, sometimes ocular migrans or encephalitis

http://2.bp.blogspot.com/_RaOrchOImw8/SnBi0RI2kpI/AAAAAAAAWGM/9U3yIEheXbo/s1600-h/billy-eating-dirt.jpg

Pathology

•Aggressive migration of larvae

•Molt and grow as migrate

•Only 5-7% enter neural (or ocular) tissue – induce an inflammatory (eosinophilic) response encephalitis

•Migrate extensively in brain before being walled off by host

•Post-inflammatory atrophy, necrosis, and impairment

Very distinctive prominent alaeexcretory columnsmultinucleate

•Encephalitis in an 11-month-old boy. •Abnormal high signal throughout most of the central white matter (arrows) compared with the dark signal expected at this age (broken arrows).•Extensive evidence of raccoon activity and fecal contamination, including 21 latrine sites, were identified on the patient’s property and the adjacent vacant lot.•11 raccoon were necropsied, all were positive.

Raccoon Roundworm

-Single adult female worm = 115,000 to 877,000 eggs per day-raccoon infected with multiple worms = shed up to 45,000,000 eggs daily

Raccoon Roundworm

midwestern U.S. documented in 68–82% of raccoons; >90% juveniles

Raccoon Roundworm

- Prevalence, intensity of infection, avg # of larvae significantly higher in the highly fragmented landscape

- Probability of infection, intensity of infection, and avg # of larvae per mouse per patch varied as functions of forest patch area and isolation (DD)

Raccoon Roundworm

• A study conducted in Northern California tried to determine if a pattern existed to the preferred location of latrines. While latrines on the ground and on roofs appeared to be the most favorable, preferences varied by location.

Raccoon Roundworm

• Percentage of California properties that contained at least one raccoon latrine positive for Baylisascaris procyonis eggs (number of properties = 164).

Raccoon Roundworm

- Eggs ~ 65 microns in size- Household disinfectants (bleach) will not kill

(remove coating)- Fire/heat, boiling water, required to kill eggs

Raccoon Roundworm: Trophic-level Effects

• Former range of the Allegheny woodrat (inside bold line), and regions where woodrats have disappeared in recent decades (stippled areas).

Raccoon Roundworm: Trophic-level Effects

• Range of raccoon roundworm in Allegheny woodrat states

Download - Sarcoptic Mange

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