Raccoons become infected when they eat an infected animal (such as rodents, rabbits and birds) or ingestBaylisascaris eggs from the soil while foraging for food. Raccoons use communal latrines for defecation, and have a habit of always defecating in the same place, resulting in large amounts of contaminated feces being present in an area.
Humans and animals, including pets, can become infected when they accidentally swallow infectious Baylisascaris eggs found in food, water, soil or other objects contaminated with raccoon feces. Young children or people with developmental disabilities who put hands and other objects into their mouths or have a habit of eating soil are may be at increased risk for infection. Once inside the body, eggs hatch into larvae and cause disease when they travel through the liver, brain, spinal cord or other organs.