1. Baylisascaris procyonis
Presented by Kayla Schaefer, Tashi Sherpa, and
Julie Sobolewski

2. Taxonomy Kingdom: Animalia Phylum: Nematoda Class: Rhabditae
Order: Ascaridida
Genus: Baylisascaris
Species: B. procyonis

3. Hosts Definitive Host: Reservoir Host: Paratenic Host:
Raccoons (Procyon lotor)
Reservoir Host:
Dogs
Paratenic Host:
Rodents
Birds
Lagomorphs
Humans

4. Geographic Distribution
North America
Infected Raccoons common in: Middle Atlantic, Midwest, Northeast, California, Georgia
Human cases found in: California, Oregon, New York, Illinois, Pennsylvania, Michigan, Minnesota

5. Questions What phylum are we talking about? Nematoda
2. What kind of a host is a human for this parasite?
Paratenic

6. Morphology
Unembryonated eggs are thick-shelled and usually oval in shape.  Their size typically is around microns by microns. 
Embryonated egg measuring 50 microns in length

7. Morphology
The adult female worms can grow to be 24 cm long, while the males can grow up to 12 cm long
Pictured here is an adult female worm on the left and an adult male worm on the right

9. Life Cycle in Adult Raccoons
Adult worms reside within the small intestines of raccoons and shed eggs which are then passed through the feces
After 30 days the eggs molt into the infective, L2 stage
The embryonated eggs are then ingested by an accidental host. The eggs hatch and the L2 larvae penetrate the small intestines and migrate throughout the whole body as they continue to grow
The L2 larvae can then either encyst or continue circulating throughout the body
An adult raccoon becomes infected when it ingests an infected accidental host

10. Life Cycle in Juvenile Raccoons
Adult worms reside within the small intestines of raccoons and shed eggs which are then passed through the feces
After 30 days the eggs molt into the infective, L2 stage
Juvenile raccoons ingest the embryonated eggs and L2 larvae hatch in the small intestines
The larvae penetrate the intestinal wall, molt to the L5 stage and enter back into the small intestines where they mature to adults
The adult worms mate and produce the next generation of eggs

12. Clinical and Pathological Signs
Symptoms of Baylisascariasis generally appear one to three weeks after ingestion, although they may take as long as two months to develop.
The severity of symptoms depends on the amount of eggs ingested. The infective dose of Baylisascaris is estimated to be 5,000 eggs or less.
There are usually no clinical or pathological signs in raccoons.
In heavy infections, intestinal obstructions or a rupture of the intestinal tract may occur, due to the large number of parasites present.
Parasite may be deadly in accidental host.

13. Clinical and Pathological Signs
Symptoms may include:
Nausea
Lethargy
Liver enlargement
Loss of muscle control
Coma
Blindness
Death

14. Pictured above is a human retina infected with larvae

15. Diagnosis In raccoons: In abnormal hosts: In humans:
Examining adult worms
Fecal floatation
In abnormal hosts:
Examining the larvae
Examining lesions in the brain, eyes, and other tissues that can be observed by a microscope
In humans:
Examining the size of the larvae in the skin or eye lesions
In the event of the death of a human, larvae can be detected in microscopic sections of the brain, heart, lungs, eyes and other affected tissues.

16. Treatment
Raccoons can be successfully treated with several antihelminthics to kill the adult worms. Effective drugs are:
piperazine, fenbendazole, pyrantel pamoate, levamisole and organophosphates such as dichlorvos.
There are currently no drugs that can effectively kill the migrating larvae in humans.
Laser surgery has been successfully performed to kill larvae present in the retina of the eye, but the damage caused by the migrating larvae is irreversible.
Treatment with steroids in paratenic hosts is mainly supportive and is designed to decrease the inflammatory reaction.

17. A female rabbit, suffering from head-tilt, before and after treatment with fenbendazole and enrofloxacin.

18. Questions Name two symptoms this parasite may cause.
Nausea, Lethargy, Liver enlargement, Loss of muscle control, Coma, Blindness, Death
What drug is effective at killing this parasite in humans?
None

19. Public Health Concerns
Emerging Helminthic Zoonosis
Human baylisascariasis
Young children
Difficult diagnosis
Low infectious dose
Raccoons proximity to humans
Egg viability
Possible Agent of Bioterrorism
Easily acquired
Low infectious dose
Severe/fatal infection
No effective therapy/vaccine

20. What to do for Control Educate medical community Educate public
Awareness concerning patients with eosinophilic meningoencephalitis, DUSN, and eosinophilic pseudotumor
Educate public
Awareness of transmission
Further research

21. Works Cited
Schmidt, G., & Roberts, L. (2005). Foundations of parasitology (7th ed.). New York, NY: McGraw-Hill.

22. Questions about Article
Relatively few human cases have been reported, what factors suggest that infection is greater than we realize?
Infected raccoons can shed 45,000,000 eggs/day, viability of eggs (months to years), proximity of raccoons to humans
From the table reporting human cases, do any seem out of place? Why?
Germany case: note the sex and the age
What are some things the public can do to help control this parasite?
Don’t keep raccoons as pets, don’t feed raccoons, protect garbage from raccoon access, discourage exposure to raccoons and their feces