A parasitic tapeworm capable of causing a lethal human disease has been detected in West Coast wildlife for the first time. Researchers from the University of Washington identified the European variant of Echinococcus multilocularis in 37 out of 100 sampled coyotes near Puget Sound, Washington State.
While the presence in wildlife is notable, researchers emphasize the risk to the general public remains low. The parasite, historically rare south of Alaska, has been spreading west from the Midwest for years. It typically cycles between canids like foxes and coyotes, and rodents.
Humans can accidentally ingest the worm's eggs through contaminated soil, food, or contact with infected pets. The resulting disease, alveolar echinococcosis, often remains undetected for years as tumor-like cysts slowly destroy the liver. In severe cases, it can mimic cancer, spread to the brain, and cause liver failure or death.
"The reason that cases are so high in coyotes is because they are regularly eating raw rodents," said lead author Yasmine Hentati. Infectious disease specialist Dr. Linda Yancey noted the highest global prevalence of human infection is in western China.
Prevention relies on vigilant hygiene. Experts recommend thorough hand washing after outdoor activity, preventing pets from eating wild rodents, and routine veterinary deworming.
Symptoms requiring medical attention include persistent abdominal pain, fatigue, and yellowing of the skin. If a cyst ruptures, the release of fluid can be fatal.