Raccoon Roundworm: Infections, Symptoms, & Prevention

A rare disease known as raccoon roundworm (sometimes mistakenly referred to as “raccoon ringworm”) has infected two people in New York City, according to published reports. One, a teenager, is said to be blinded in one eye by the infection. The other, an infant, is reportedly brain-damaged.

Raccoon Roundworm: Baylisascaris

Raccoon roundworm is a worm transmitted via contact with raccoon feces. Technically called baylisascaris, the worms develop in a raccoon’s intestine. They create millions of eggs, which then are passed out with the feces and become infective to other creatures. The eggs are able to survive for years even in harsh environmental conditions, according to the Centers for Disease Control.

Image courtesy Stanford University

Raccoon Roundworm: Human Infections

Humans are typically infected by accidentally ingesting the raccoon roundworm eggs, the CDC says, by coming into contact with soil or water that’s touched the raccoon feces. Once the roundworm is inside a person’s system, it hatches and spreads throughout the body, affecting both organs and muscles.

Raccoon roundworm infections are incredibly uncommon in humans. The CDC reports less than 25 cases officially diagnosed since 2003. Five of those cases resulted in death.

Symptoms of raccoon roundworm can include nausea, fatigue, enlarged liver, decreased coordination, decreased attention to one’s environment, loss of muscle control, coma, and blindness.

Raccoon Roundworm: Treatment and Prevention

Doctors can deliver treatment that, if started early enough, can prevent a raccoon roundworm infection from reaching its most serious stages.

As for prevention, the CDC recommends the following:

• Avoid direct contact with raccoons – especially their feces. Do not keep, feed, or adopt raccoons as pets! Raccoons are wild animals.
• Discourage raccoons from living in and around your home or parks by:
  — preventing access to food
  — closing off access to attics and basements
  — keeping sand boxes covered at all times, (becomes a latrine)
  — removing fish ponds – they eat the fish and drink the water
  — eliminating all water sources
  — removing bird feeders
  — keeping trash containers tightly closed
  — clearing brush so raccoons are not likely to make a den on your property
• Stay away from areas and materials that might be contaminated by raccoon feces. Raccoons typically defecate at the base of or in raised forks of trees, or on raised horizontal surfaces such as fallen logs, stumps, or large rocks. Raccoon feces also can be found on woodpiles, decks, rooftops, and in attics, garages, and haylofts. Feces usually are dark and tubular, have a pungent odor (usually worse than dog or cat feces), and often contain undigested seeds or other food items.
• To eliminate eggs, raccoon feces and material contaminated with raccoon feces should be removed carefully and burned, buried, or sent to a landfill. Care should be taken to avoid contaminating hands and clothes. Treat decks, patios, and other surfaces with boiling water or a propane flame-gun. (Exercise proper precautions!) Newly deposited eggs take at least 2-4 weeks to become infective. Prompt removal and destruction of raccoon feces will reduce risk for exposure and possible infection.
• Contact your local animal control office for further assistance.

For more information, see the CDC’s fact sheet on the baylisascaris infection.