A King County, Washington toddler may have contracted the parasitic infection, Baylisascaris procyonis, or the raccoon roundworm, county health officials report. The Centers for Disease Control and Prevention (CDC) is testing specimens from the child’s blood and spinal fluid and results are expected in two weeks. The toddler was hospitalized but is now recovering at home.

Raccoon image/CDC
Raccoon image/CDC

If confirmed, it would be the first such case in Washington State.

Baylisascaris procyonis is a roundworm found in the small intestines of raccoons. They excrete the eggs of this parasite in their feces. The eggs can survive in the environment for years under favorable conditions. There can be millions of eggs shed by the raccoon, with high densities in the feces and the soil surrounding it.

LISTEN: Interview with Baylisascaris expert and Professor Emeritus of Veterinary Parasitology at the Purdue University College of Veterinary Medicine, Kevin Kazacos, DVM, PhD

Humans and animals get infected by accidentally ingesting eggs from the environment, from raccoon feces, contaminated water or fomites. Raccoons typically defecate in favored areas called latrines. Common latrines include the bases of trees, raised forks of trees, fallen logs, rooftops, woodpiles and decks.

The infection can be severe and even fatal if the roundworms enter a person’s eye, organs, or brain. Baylisascariasis does not spread person-to-person.

Symptomatic infection in humans is relatively rare with less than 3 dozen cases reported; however, new University of Georgia research suggests there can be asymptomatic infections.