Baylisascaris procyonis is a roundworm found in raccoons. The raccoons eat a piece of contaminated food that has the egg on it. The egg then matures in the raccoon into an adult in the small intestine which are passed into the feces and into the world. Rabbits, muskrats and other small critter then eat the grasses contaminated with the eggs that came from the raccoon and the cycle continues. The challenge is when a water source gets contaminated with raccoon feces or when a human has a pet raccoon with the parasite. If they accidentally pass the feces into their mouth the parasite can penetrate the gut wall and head straight to the brain making it mush. Yikes. Please treat all pet raccoons with a round wormer three times a year and wash your hands thoroughly after handling the critter.

Baylisascaris egg from a fecal sample: 

Baylisascaris egg in a fecal sample

Baylisascaris lifecycle: 

Baylisascaris life cycle

Helpful Links and References:

• Baylisascaris as an emerging disease (and other things you campers and hikers should watch out for: https://naturalunseenhazards.wordpress.com/2010/10/26/geographic-expansion-of-baylisascaris-procyonis-roundworms-florida-usa/
• MRI of a 13-year old boy who died of Baylisascaris: https://www.cdc.gov/ncidod/eid/vol8no4/01-0273-G1.htm