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Baylisascaris Procyonis

(Raccoon roundworm)

This is a large roundworm parasite that lives in the intestines of raccoons. The worm does not harm the raccoon, but on rare occasions can cause serious illness in humans. About half of all raccoons tested in Wisconsin have been found to be infected. Raccoons throughout Wisconsin have shown to be infected with Baylisascaris procyonis, but it is more prevalent in the southern portion of the state.

Baylisascaris Procyonis 101

People become infected by ingesting infectious eggs. Most infections are in children and others who are more likely to put dirt or animal waste in their mouth by mistake.

The incubation period (time from exposure to symptoms) is usually one to four weeks. If present, signs and symptoms can include the following:

  • Nausea
  • Tiredness
  • Liver enlargement
  • Loss of coordination
  • Lack of attention to people and surroundings
  • Loss of muscle control
  • Blindness
  • Coma

A health care provider can discuss treatment options with you. No drug has been found to be completely effective against Baylisascaris infection in people. Albendazole has been recommended for some cases.

Eggs passed in raccoon feces are not immediately infectious. In the environment, eggs take two to four weeks to become infectious. If raccoons have set up a den or a latrine (places where raccoons defecate) in your yard, raccoon feces and material contaminated with raccoon feces should be removed carefully and burned, buried, or sent to a landfill. Care should be taken to avoid contaminating hands and clothes. Treat decks, patios, and other surfaces with boiling water or a propane flame-gun (exercise proper precautions). Prompt removal and destruction of raccoon feces before the eggs become infectious will reduce risk for exposure and possible infection.

Do not keep, feed, or adopt wild animals, including raccoons, as pets.

Washing your hands after working or playing outdoors is good practice for preventing a number of diseases.

Questions about Baylisascaris Procyonis (Raccoon roundworm)? Contact us!
Phone: 608-267-9003 | Fax: 608-261-4976

Wisconsin Local Health DepartmentsRegional officesTribal agencies

Last revised March 22, 2024