What is Racoon Roundworm Disease?
Racoon roundworm disease is an intestinal parasitic infection caused by Baylisascaris worms. This roundworm can infect people as well as a variety of other animals, including dogs. Human infections are rare but can be severe if the parasites invade the eye (ocular larva migrans), organs (visceral larva migrans) or the brain (neural larva migrans).
How does it spread?
People become infected by consuming infectious eggs. Most infections are in children and others who are more likely to put dirt or animal waste in their mouth by mistake.
Prevention
Eggs passed in raccoon feces are not immediately infectious. In the environment, eggs take 2 – 4 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 buried or sent to a landfill. Take steps to avoid contaminating your hands and clothes. Treat decks, patios, and other surfaces with boiling water 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.
Symptoms
Symptoms can appear 1-4 weeks after exposure and may include:
- Nausea
- Tiredness
- Lack of Attention to People and Surroundings
- Blindness
- Loss of Coordination
- Loss of Muscle Control
- Coma
Information for the Public
Los Angeles County Department of Public Health recently learned of two cases of raccoon roundworm. Although the risk to the general public remains low, there are several steps you can take to decrease your family’s risk:
- Do not feed raccoons or keep them as pets.
- Do not feed wildlife and avoid leaving open sources of food for community cats.
- Feed household pets indoors and never leave pet food or water sources outdoors as it can attract wildlife.
- Pick up and throw away other possible food sources around homes such as fruit that has fallen from trees.
- Keep all trash in tightly closed containers.
- Close off access to basements, attics, and crawl spaces and clear brush and trees away from your property and roof line to discourage raccoons from sleeping or defecating nearby.
- Cover all sandboxes when not in use, as raccoons may defecate in sandboxes.
- Be aware that raccoons and other wildlife may also be attracted to fishponds, and bird feeders.
If there are raccoon feces in your house or neighborhood, take steps to remove them:
- Avoid contaminating hands and clothes. Wear disposable gloves, rubber boots that can be scrubbed or cover your shoes with disposable booties that can be thrown away. Wear a well-fitting N95-rated respirator.
- If the feces are dry, avoid creating fecal dust. Spray a small amount of water or place damp paper towels over the feces.
- Pick up the raccoon feces using a shovel or inverted plastic bag. Double bag them, seal tightly and then discard in a closed outdoor trash bin.
- Pick up and discard other possible food sources around homes such as fruit that has fallen from trees.
- Clean off any remaining visible feces from location or tools with detergent and water.
- Decontaminate hard smooth surfaces (including shovels) by applying boiling water or by using a steam cleaner. Note that most chemicals do not kill raccoon roundworm eggs, but high heat kills them instantly.
- Remove and discard gloves. Wash clothing in high heat and detergent. Wash your hands with soap and clean water.
- If a space/area is too difficult or unsafe to reach, then it may be necessary to hire a private company for clean up.
Information for Providers
The clinical presentation of Baylisascariasis depends on the number and the location of larvae in the body. Non-specific signs and symptoms may appear as soon as one week post-infection and include but are not limited to nausea, fever, and lethargy.
- Neural larva migrans often presents as acute eosinophilic meningoencephalitis. Signs and symptoms may include weakness, incoordination, ataxia, irritability, weakness, seizures, altered mental status, stupor, and/or coma.
- Ocular larva migrans may present as diffuse unilateral subacute neuroretinitis with photophobia, retinitis, and/or blindness. Can occur with neural larva migrans or alone.
- Visceral larva migrans may be associated with macular rash, abdominal pain, hepatomegaly, and pneumonitis. Larvae can cause inflammatory reactions in organs and tissue damage. Skin infection and inflammation have been reported
Consider Baylisascariasis infection in persons with severe developmental disabilities or pica/geophagia and sudden onset of eosinophilic encephalitis. A history of exposure to raccoons or their feces is highly suggestive but not necessary.
Additional Resources
For information on Raccoon Roundworm in animals, visit LA County Veterinary Public Health.