Baylisascariasis: A Potential
Local Threat
Joshua Sabey
BIOL 4800
Emerging Diseases
•
•
•
•
•
•
•
•
HINI (Swine Flu)
Avian influenza (Bird Flu)
Severe acute respiratory syndrome (SARS)
West Nile virus
Bovine Spongiform Encephalopathy (Mad Cow)
Staphylococcus aureus (Antibiotic Resistance)
Plasmodium (Malaria)
Baylisascaris procyonis (Raccoon Ascaris)
Baylisascaris procyonis
Eggs
• Nematode
• Dioecious
• Thick cuticle
Larvae
Adults
Life-Cycle
Life-Cycle Specifics
• Final host is Raccoon.
• Has a wide range of intermediate hosts
including birds, squirrels, woodchucks, and
rabbits.
• Larvae can also infect humans and cause
major problems.
Raccoon Range
Raccoon Range Expansion
•
•
•
•
•
Raccoon harvest
1000 pelts or more
MB = 1967
SK = 1972
AB = 1983
Expansion Reasons
1. Anthropogenic Resources
• Food availability (Garbage and food crops).
• Den availability (Trees in parks or yards,
chimneys, and attics).
2. Global Warming
• Longer growing season = more food.
• Mild winters = increased hibernation survival.
Raccoon Problems
• Average 20,000 eggs per gram of feces.
• Also common carriers of rabies and canine
distemper.
The Urban Raccoon
Raccoon Latrines
Prevalence in Urban Areas
• Percentage of yards surveyed that had
latrines: Chicago = 51%, San Jose = 49%.
• Percentage of latrines surveyed that were
infective: Winnipeg = 50%, San Jose = 53%.
• Percentage of captured individuals that were
infected: Winnipeg = 50%.
• Some areas in Florida have an infection rate of
up to 82%.
Pathology
CLM
VLM
OLM
• Children are at highest risk by playing in yards
and parks.
Pathology
• Baylisascaris procyonis larval migration is
more aggressive.
• Larvae are larger and grow during migration.
• Results in more damage to tissues.
• Releases toxic proteins causing inflammation.
• CLM = intense itching.
• VLM = abdominal pain.
• OLM = partial or total loss of vision.
NLM
Initial Picture
2 Weeks Later 6 Weeks Later
• Encephalitis: inflammation of the brain.
• Progressive neurological decline.
• Treatment does not prevent damage.
Treatment
• OLM are treated through surgical removal or
direct laser photocoagulation.
• All other LM are treated with antihelminthic
medications.
• Despite treatment, there are no documented
neurologically intact survivors of NLM.
• 40% of documented cases were fatal.
• 73% of documented cases were children
under 3.
Conclusions
• Raccoon range expansion North and West into
Canada is making baylisascariasis a potential
local problem.
• Increased Raccoon populations in urban areas
are increasing human exposure rates.
• Since treatment is not effective, emphasis
should be put on prevention of exposure.
References
Gavin PJ, Kazacos KR, and Shulman ST (2005). Baylisascariasis. Journal of Clinical Microbiology. 18:703718.
Lariviere S (2004). Range expansion of raccoons in the Canadian prairies: review of hypotheses. Wildlife
Society Bulletin. 32:955-963.
Mehta P, Boyd Z, and Cully B (2010). Raccoon roundworm encephalitis. Pediatric Radiology.
1836.
11:1834-
Page LK, Anchor C, Luy E, Kron S, Larson G, Madsen L, et al. (2009). Backyard raccoon latrines and risk
for Baylisascaris procyonis transmission to humans. Emerging Infectious Diseases. 15:1530-1531.
Roussere GP, Murray WJ, Raudenbush CB, Kutilek MJ, Levee DJ, and Kazacos KR (2003). Raccoon
roundworm eggs near homes and risk for larva migrans disease, California communities.
Emerging Infectious Diseases. 9:1516-1522.
Sexsmith JL, Whiting TL, Green C, et al. (2009). Prevalence and distribution of Baylisascaris procyonis in
urban raccoons (Procyon lotor) in Winnipeg, Manitoba. Canadian Veterinary Journal. 8:846-850.
Shafir SC, Wise ME, Sorvillo FJ, et al. (2006). Central nervous system and eye manifestations of infection
with Baylisascaris procyonis. Current Infectious Diseases Report. 4:307-13.