Washington coyotes found carrying Echinococcus multilocularis

A University of Washington study has identified Echinococcus multilocularis in coyotes from the Puget Sound region, marking the first reported detection of the zoonotic tapeworm in a wild host on the contiguous U.S. West Coast. Researchers tested 100 coyotes collected between 2021 and 2024 and found the parasite in 37, with results published March 24, 2026, in PLOS Neglected Tropical Diseases. The study adds wildlife evidence to a pattern that had already started to emerge in domestic animals: the authors note that since 2023, five Washington dogs have been reported with E. multilocularis, alongside additional cases in Oregon and Idaho. (journals.plos.org)

Why it matters: For veterinarians, the finding raises the profile of a parasite that may still be unfamiliar in routine small-animal practice in the Pacific Northwest. Dogs can serve as definitive hosts and shed eggs without obvious illness, or, if exposed to eggs, develop alveolar echinococcosis with tumor-like liver lesions. The study authors and CDC both point to practical prevention steps that are directly relevant in clinic conversations with pet parents: keep dogs from hunting rodents or scavenging carcasses, reduce exposure to coyote feces, and consider parasite prevention and diagnostic follow-up when risk factors are present. (washington.edu)

What to watch: Expect more surveillance in wildlife and domestic dogs, and closer attention to whether Washington veterinary case finding uncovers additional canine infections now that the parasite’s local wildlife cycle has been confirmed. (journals.plos.org)