Baylisascaris

Baylisascaris infection is caused by a roundworm found in raccoons.

Baylisascaris procyonis egg with larva

Types

• This roundworm can infect people as well as a variety of other animals, including dogs.
• Human infections are rare, but can be severe if the parasites invade the eye (ocular larva migrans), organs (visceral larva migrans) or the brain (neural larva migrans).

Epidemiology

• Cases of Baylisascaris infection in people are not frequently reported but can be severe.
• Baylisascaris procyonis is thought to pose the greatest risk to people because of the often close association of raccoons to human dwellings.

Geographic distribution

• Baylisascaris procyonis has been identified in the United States, Europe, and Japan.
• Some evidence of infection in animals has been reported in South America.
• In the United States, infected raccoons have been found in a number of states, especially in the mid-Atlantic, Midwestern states and West Coast states.

Baylisascaris procyonis life cycle

Transmission

People become infected by ingesting infectious eggs. Most infections are in children and others who are more likely to put dirt or animal waste in their mouth by mistake.

Signs and symptoms

The incubation period (time from exposure to symptoms) is usually 1 to 4 weeks. If present, signs and symptoms can include the following:

• Nausea
• Tiredness
• Liver enlargement
• Loss of coordination
• Lack of attention to people and surroundings
• Loss of muscle control
• Blindness
• Coma

Diagnosis

There are no widely available tests, so the diagnosis is often made by ruling out other diseases.

Treatment

• No drug has been found to be completely effective against Baylisascaris infection in people.
• Albendazole has been recommended for some cases.