What is Baylisascaris infection?
Baylisascaris, an intestinal raccoon roundworm, can infect a variety of other animals, including humans. The worms develop to maturity in the raccoon intestine, where they produce millions of eggs that are passed in the feces. Released eggs take 2-4 weeks to become infective to other animals and humans. The eggs are resistant to most environmental conditions and with adequate moisture, can survive for years.
How do humans become infected?
People become infected when they accidentally ingest infective eggs in soil, water, or on objects that have been contaminated with raccoon feces.
When humans ingest these eggs, they hatch into larvae in the person's intestine and travel throughout the body, affecting the organs and muscles.
Who is at risk for infection?
Anyone who is exposed to environments where raccoons live is potentially at risk. Young children or developmentally disabled persons are at highest risk for infection when they spend time outdoors and may put contaminated fingers, soil, or objects into their mouths. Hunters, trappers, taxidermists, and wildlife handlers may also be at increased risk if they have contact with raccoons or raccoon habitats.
How common is Baylisascaris infection in raccoons?
Fairly common. Infected raccoons have been found throughout the United States, mainly in the Midwest, Northeast, middle Atlantic, and West coast. Infection rarely causes symptoms in raccoons. Predator animals, including dogs, may also become infected by eating a smaller animal that has been infected with Baylisascaris.
How do raccoons become infected?
Raccoons become infected in one of two ways:
- Young raccoons become infected by eating eggs during foraging, feeding, and grooming.
- Adult raccoons acquire the infection by eating rodents, rabbits, and birds infected with the larvae of Baylisascaris.
How common is Baylisascaris infection in humans?
Infection is rarely diagnosed. Fever than 25 cases have been diagnosed and reported in the United States as of 2003. However, it is believed that cases are mistakenly diagnosed as other infections or go undiagnosed. Cases have been reported in Oregon, California, Minnesota, Illinois, Michigan, New York, and Pennsylvania. Five of the infected persons died.
