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
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
Raccoon roundworm - Baylisascaris procyonis
Definitive host
Life cycle is direct or indirect depending on age of raccoon
Raccoon roundworm - Baylisascaris procyonis
Adults in intestines lay eggs
Raccoon roundworm - Baylisascaris procyonis
Eggs are shed with feces
Raccoon roundworm - Baylisascaris procyonis
Eggs are shed with feces – loads of ‘em
Raccoon roundworm - Baylisascaris procyonis
Sticky, proteinaceous outer coat
Raccoon roundworm - Baylisascaris procyonis
Over 2-4 weeks the eggs develop larvae
Raccoon roundworm - Baylisascaris procyonis
Can remain infectious for years
Raccoon roundworm - Baylisascaris procyonis
Embryonated egg with larvae is ingested by young raccoon -- Direct
Raccoon roundworm - Baylisascaris procyonis
Egg hatches in to larva
Raccoon roundworm - Baylisascaris procyonis
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
Raccoon roundworm - Baylisascaris procyonis
Embryonated egg with larvae are ingested by intermediate hosts
Raccoon roundworm - Baylisascaris procyonis
Eggs hatch and release larvae into intestines gut wall migrate thru the various tissue (larval migrans) causing considerable damage and then encyst
Raccoon roundworm - Baylisascaris procyonis
In the eye blindness
Raccoon roundworm - Baylisascaris procyonis
5-7% CNS disease
Raccoon roundworm - Baylisascaris procyonis
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
Raccoon roundworm - Baylisascaris procyonis
Raccoon roundworm - Baylisascaris procyonis
Definitive host??
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
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