Dangerous Tapeworm Detected in Pacific Northwest Wildlife

Researchers from the University of Washington have identified the presence of the tapeworm *Echinococcus multilocularis* in coyotes across the Puget Sound region. This discovery marks the first time the parasite has been confirmed in wild animals along the U.S. West Coast. Testing revealed that 37% of the sampled coyote population carried the parasite, a prevalence rate that surprised researchers given the region's previous history as a parasite-free zone.

While *E. multilocularis* is typically asymptomatic in its primary hosts—coyotes and foxes—it poses a significant health risk to humans and domestic dogs. The parasite causes alveolar echinococcosis, a condition characterized by the development of slow-growing, cancer-like cysts in the liver and other vital organs. Because these cysts can take over a decade to manifest symptoms, the infection is often difficult to diagnose and treat, leading to potential fatalities if left unaddressed.

The parasite spreads through a cycle involving canids and rodents, with humans becoming accidental hosts through the ingestion of eggs found in contaminated environments. As the parasite continues its expansion across North America, this finding highlights a growing public health challenge. The World Health Organization classifies this condition as a major neglected tropical disease, underscoring the need for increased awareness among pet owners and the public regarding hygiene and exposure risks in areas where the parasite has now established a foothold.