Baylisascaris, more commonly called raccoon roundworm, is an intestinal worm that can infect a variety of animals, including humans. The infection is usually contracted through accidental contact with contaminated soil, water or feces.

Young children are at particular risk when they play in the dirt and then put their hands in their mouths. Eggs hatch into larvae in the intestine and travel throughout the body, inflaming organs and muscles. The disease is rare and difficult to diagnose because it has a wide range of fairly nonspecific symptoms such as inflammation, pain, nausea, fatigue, seizures, paralysis and even vision problems.