Baylisascariasis (Raccoon Roundworm)

What is baylisascariasis?

Baylisascariasis is a disease caused by infection with a roundworm that is commonly found in racoons (Baylisascaris procyonis). Baylisascaris worms grow inside raccoon intestines, where they produce eggs that are passed in the feces. After 2-4 weeks in the environment, these eggs become infectious to humans and other animals, including dogs. People and animals can become infected when they ingest these eggs in soil, sand, water, or on objects contaminated by racoon feces. Human infection is rare but disease can be severe .

Where is it found?

Raccoons infected with Baylisascaris procyonis have been identified across the United States, including in Washington state, as well as in other countries.

Raccoons commonly live in or around areas where people live. Raccoons defecate in communal sites, called latrines. Many raccoons may use the same latrine. Raccoon latrines are often found at the bases of trees, in unsealed attics, or on flat surfaces such as logs, tree stumps, rocks, decks, and rooftops. These latrines are likely to contain roundworm eggs that can live in the environment for several years.

How is it spread?

People become infected when they ingest infectious raccoon roundworm eggs. Most infections occur in young children or persons with developmental disabilities who are more likely to put contaminated objects, dirt, or sand in their mouth. Hunters, trappers, taxidermists, pest control operators, and wildlife handlers may also be at increased risk of infection if they have contact with raccoons or raccoon latrines.

Baylisascaris infection is not contagious, so one person cannot give the infection to another.

How can infection with Baylisascaris be prevented?

Do not feed raccoons or keep them as pets.
Keep children and pets away from raccoon latrines.
If you or a family member may have ingested raccoon feces, immediately contact your healthcare provider, who may recommend treatment to prevent disease.
Wash hands with soap and warm water after working or playing outside.
Discourage raccoons from living in and around your home.
- Don’t leave food out and keep your garbage cans secure.
- If you have an attic, crawlspace, or basement, ensure possible entrances are closed.
- Cover sandboxes.
- Eliminate water sources, including fish ponds.
- Remove bird feeders.
- Keep brush clear so raccoons don’t make a den on your property.
Keep an eye out for raccoon feces in and around your yard.
- Routinely check gardens, log piles, playgrounds, fence lines, roofs, decks, and other places around your property for raccoon feces or latrines. Raccoon feces are dark and tube shaped.
- If you discover a raccoon latrine, take care to avoid infection when removing or cleaning it
  - Cleaning up an outdoor latrine:
    - Wear disposable gloves
    - Wear rubber boots that can be scrubbed so that you do not bring eggs inside
    - Remove feces and material contaminated with raccoon feces and burn, bury, or double bag and place in the trash.
    - Treat feces-soiled decks, patios, and other outdoor surfaces with boiling water or a propane torch to kill remaining eggs.
    - Wear disposable gloves
    - Wear an N95 respirator
    - Avoid stirring up dust by spraying the area with water from a spray bottle before cleaning
    - Remove feces and material contaminated with raccoon feces and burn, bury, or double bag and place in the trash.
    - Use a damp sponge to wipe the area with hot soapy water. Rinse your sponge frequently and discard the sponge by double bagging and placing in the trash.

What is the treatment?

No drug has been found to be completely effective against Baylisascaris infection in people, but treatment has been shown to decrease the severity of disease. Albendazole is usually recommended for suspect or confirmed cases.