A baylisascaris infection is an infection caused by an intestinal raccoon roundworm that 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. The infection is rarely diagnosed, and can cause severe damage and lead to death in humans if left undiagnosed and untreated.