/Raccoon Roundworm Infection (Baylisascaris procyonis)

Raccoon Roundworm Infection (Baylisascaris procyonis)

What is Baylisascaris infection?

Baylisascaris procyonis is a large roundworm that lives in the intestines of raccoons.

Adult worms can measure 5 to 8 inches long and 1/2 inch wide. The adult worms shed millions of microscopic eggs that are passed in the raccoon’s feces. The worm does not harm the raccoon, but can cause serious illness in humans.

Symptoms can include:

  • Nausea
  • Lethargy
  • Liver enlargement
  • Loss of muscle control
  • Coma
  • Blindness
  • Death

Baylisascaris procyonis is increasingly being recognized as a cause of severe human disease.

How is Baylisascaris spread?

People become infected with Baylisascaris when they ingest eggs in soil, water, or on objects that have been contaminated with raccoon feces.

Children, particularly toddlers, are at higher risk of exposure as they may put contaminated fingers, soil or objects in their mouth.

These eggs are resistant to most environmental conditions, and with adequate water, can survive from months to years. When humans ingest these eggs, they hatch into larvae in the person’s intestine and migrate throughout the body, affecting the organs and muscles.

How soon after exposure do symptoms appear?

Symptoms of Baylisascariasis generally appear one to three weeks after ingestion, although they may take as long as two months to develop.

The severity of symptoms depends on the amount of eggs ingested. The infective dose of Baylisascaris is estimated to be 5,000 eggs or less.

How is Baylisascariasis diagnosed?

Baylisascariasis can be diagnosed in humans based on observation of the larvae in the skin or eye lesions. Infection can also be diagnosed by ruling out other infections that cause similar symptoms.

Since 1980, 11 human cases of Baylisascariasis have been reported in the United States, four of them fatal.

What is the treatment for Baylisascariasis infection?

Currently there are no drugs that can effectively kill the migrating larvae in the body. Laser surgery has been successful in killing larvae present in the retina of the eye but the damage caused by the migrating larvae is irreversible.

How can Baylisascariasis be prevented?

Controlling Baylisascaris procyonis requires avoiding contact with raccoons and areas inhabited by raccoons.

  • Discourage raccoons from visiting your home or yard by eliminating access to food sources like pet food, garbage cans and bird feeders.
  • Raccoons may nest in wood piles, attics, chimneys, sheds and barn lofts.
  • Raccoons should not be kept as pets; they are dangerous wild animals that can carry other diseases such as rabies and plague.

How should I clean up raccoon feces?

  • Materials contaminated with raccoon feces should be carefully removed and buried, burned, or bagged and disposed of in a landfill.
  • Wear disposable gloves, boots and a dust mask when disposing of contaminated material.
  • Contaminated surfaces can be decontaminated by flaming with a propane torch (concrete and other non flammable surfaces) or with boiling Lysol.

Where can I get more information?

Contact your doctor or the Southern Nevada Health District, Office of Epidemiology at (702) 759-1300.


Contact Information

(702) 759-1000

Updated on: August 16, 2018

Skip to content