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Raccoon Roundworm (Baylisascaris procyonis Infection)


Raccoons are plentiful in the urban environment, however, we must remember they are wild animals, and can potentially cause injury or illness. A significant number of raccoons carry a roundworm, Baylisascaris procyonis, and shed it in their feces. This parasite can cause serious illness in humans. Although this illness is very rare, it is important to recognize the presence of "raccoon latrines", remove them safely and properly, and protect yourself and your children against ingesting the parasite's eggs.

Baylisascaris procyonis is a raccoon roundworm that can infect other animals and, rarely, humans.

A high percentage of raccoons are infected with baylisascaris. These roundworms grow in the raccoons’ intestines and produce millions of eggs that are shed into the environment in the raccoons' feces. After 2-4 weeks in the environment, eggs become infectious; under the right conditions, eggs can survive in the soil for years.


Baylisascaris infection may cause:

  • Nausea
  • Fatigue
  • Loss of coordination and muscle control
  • Inability to focus attention
  • Enlargement of the liver
  • Blindness
  • Coma

Symptoms start approximately a week after exposure. 

The infection can be fatal. Up to 2003, five deaths due to baylisascaris infection were reported in the U.S.



Raccoons become infected when they eat an infected animal (such as rodents, rabbits and birds) or ingest Baylisascaris eggs from the soil while foraging for food. Raccoons use communal latrines for defecation, and have a habit of always defecating in the same place, resulting in large amounts of contaminated feces being present in an area. 

Humans and animals, including pets, can become infected when they accidentally swallow infectious Baylisascaris eggs found in food, water, soil or other objects contaminated with raccoon feces. Young children or people with developmental disabilities who put hands and other objects into their mouths or have a habit of eating soil are may be at increased risk for infection. Once inside the body, eggs hatch into larvae and cause disease when they travel through the liver, brain, spinal cord or other organs.


It is difficult to test for baylisascaris - diagnosis is usually by process of eliminating other possibilities.


If you or your child have come into contact with raccoon feces and potentially ingested raccoon fecal matter, see your doctor and tell them about the exposure.

No drugs have been demonstrated to be totally effective for the treatment of baylisascariasis, but early detection and treatment with available medication may help.


If you have seen raccoons on your property or in the neighbourhood, check your property for evidence of raccoon latrines and dens. Raccoon latrines may be located at the base of trees, on flat surfaces such as logs, rocks, woodpiles or structures such as decks, patios, roofs and in attics or garages. 

Ensure that children do not have access to areas where raccoons are, or have been living. Wash your hands and your children’s hands thoroughly after playing outside. Discourage young children from putting their hands or fingers in their mouths. 

Remove raccoon latrines and dens from your property. This is especially important if children are playing in the yard. If you need assistance with identification of latrines and dens, contact a local pest control company. 

Be careful when cleaning up the feces of raccoons:

  • Wear gloves. A face mask will prevent inadvertent ingestion of eggs from contaminated hands.
  • Avoid getting fecal matter on your clothes.
  • Burn, bury or double bag the feces and put in the garbage.
  • Use boiling water to treat fecally contaminated areas such as decks and patios. Other disinfectants are not effective against Baylisascaris.
  • Wash your hands with liquid soap and water after removing gloves.

Do not make your property inviting to raccoons:

  • Do not keep or treat raccoons as pets. Raccoons are wild animals.
  • Do not feed raccoons.
  • Do not leave pet food outside.
  • Make bird feeders spill proof and ensure that raccoons cannot get to them. Store garbage in cans with lids that lock tightly. Cover sandboxes so they do not become raccoon latrines. Remove drinking water sources for raccoons such as ponds and other standing water.
  • Remove brush and other materials from your property where raccoons could make their dens.
  • Seal all access points to the house and other buildings, including basements and attics.

Visit the U.S. Centers for Disease Control and Prevention website to learn more about raccoon roundworm infection.


Last Updated: February 4, 2011

SOURCE: Raccoon Roundworm (Baylisascaris procyonis Infection) ( )
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