Baylisascariasis: A Potential Local Threat

Joshua SabeyBIOL 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 Larvae Adults

• Nematode• Dioecious• Thick cuticle

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.

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