infectious diseases
Baylisascariasis
Introduction
Baylisascariasis is a rare infection with the raccoon ascarid,Baylisascaris procyonis, which may cause fatal central nervous system (CNS) infection, ocular disease, or a visceral larva migrans syndrome in humans. (See also Approach to Parasitic Infections .) Infection usually occurs in children who play in dirt or with articles contaminated with raccoon feces. Most cases have been reported in the Middle Atlantic, Midwest, and Northeast of the United States. Although baylisascariasis is rare in people, it is of concern because a large number of raccoons live near humans and the infection rate ofB. procyonisin these animals is high. Infected raccoons shed millions of eggs daily in their feces; the eggs can survive in the environment for years. Humans become infected by ingesting infective eggs. After ingestion by humans, the eggs hatch into larvae. Nonspecific symptoms such a fever, lethargy, and nausea may develop as early as a week after ingestion. The larvae migrate through a wide variety of tissues (liver, heart, lungs, brain, eyes), resulting in visceral larva migrans and ocular larva migrans, similar to those due to Toxocariasis . However, in contrast to The severity of neurologic disease in humans varies depending on the Number of eggs ingested Number of larvae migrating in the CNS Tissue damage and symptoms and signs of baylisascariasis are often severe becauseBaylisascarislarvae tend to wander widely and do not readily die. 