October 5, 2009
Raccoon Roundworm
Be aware of Baylis
Note: This text is based on material originally provided by Don Burton, DVM, founder Ohio Wildlife Center
Common name: Raccoon Roundworm
Scientific name: Baylisascaris procyonis
Animal Host: Raccoon
How this disease infects people
Symptoms
Prevention
How this disease infects people
Raccoon roundworm is a zoonotic disease, meaning that it can infect both animals and people; it’s caused by a roundworm parasite, Baylisascaris procyonis. Related species of roundworm are found in bears, skunks, and other animals.
People can become infected by swallowing roundworm eggs. The eggs hatch larvae that move through and live in internal organs and tissues. Different forms of the disease are named for the part of the body affected: cutaneous (skin), ocular (eyes), neural (brain, spinal cord), and visceral (organs) larval migrans.
Baylisascaris adults live in raccoons’ intestines and rarely cause adult raccoons harm. But adult roundworms shed eggs that pass out of the raccoons via their feces.
People in contact with raccoons and their feces have the highest risk of exposure. A few factors can increase people’s risk of exposure:
- Raccoon populations can be dense in urban areas.
- Roundworm can be common in raccoons.
- Roundworm eggs can infect people months after they are shed.
Symptoms
In people, Baylisascaris mostly causes minor tissue damage and ends with the parasite encapsulated in non-critical sites such as skeletal muscle.
Large numbers of the parasite, however, can have a more significant effect. Serious—but rare—symptoms can include organ damage, loss of coordination, exhaustion, coma, blindness, and lung conditions similar to pneumonia. Central nervous system disease is possible if the parasite enters the brain.
Prevention
To prevent infection, avoid contact with raccoon feces and wash any places feces have been.
Although the eggs are resistant to environmental and chemical disinfectants, washing surfaces with a 5% bleach solution can break down their sticky coat and allow them to be flushed away. Note that the eggs may persist in soil for long periods, apparently even years.
Raccoons use established places repeatedly as “latrines.” Since old woodpiles can be favored latrines, wear protective clothes (coveralls and gloves) when handling logs and other exposed material.