Coyotes roaming Seattle-area parks are carrying more than just attitude this spring. A new University of Washington study has found that over a third of sampled coyotes across the Puget Sound region were infected with a parasitic tapeworm that can sicken dogs and, in rare cases, people. The culprit, Echinococcus multilocularis, forms slow-growing, tumor-like cysts that typically take hold in the liver. The timing is not great for anyone who walks their dog in local greenbelts, as coyotes are especially active and visible right now while tending pups and defending their dens.
Study finds parasite in local coyotes
The research, published March 24 in PLOS Neglected Tropical Diseases, examined 100 coyote carcasses and fecal samples from around the region and detected E. multilocularis in 37 animals. Lead author Yasmine Hentati and other UW researchers describe this as the first time the parasite has been confirmed in a wild host on the West Coast. Positive samples were traced to multiple locations, including Whidbey Island, Everett and Seattle, according to University of Washington.
What that could mean for dogs and people
The Centers for Disease Control and Prevention notes that the parasite's eggs are shed in canid feces, and if those microscopic eggs are accidentally swallowed, they can cause a serious condition called alveolar echinococcosis. Symptoms can take years to show up, which is part of what makes this infection so tricky, and treatment is often no quick fix. Surgery plus long-term antiparasitic medication is frequently needed, so getting prompt veterinary or medical care when there is a concern becomes especially important.
How to protect your pets
Fortunately, the basic precautions are not complicated. The Washington Department of Fish and Wildlife advises keeping dogs on short leashes in parks and greenbelts, not allowing pets to scavenge rodents or animal carcasses, and never feeding or approaching coyotes, no matter how bold or curious they seem. Veterinarians and UW researchers also recommend staying up to date on routine deworming and parasite screening, and contacting your vet if your dog has eaten rodents or been off leash in areas where coyote activity is common.
Researchers call for more surveillance
The study's authors say Washington should not treat this as a one-and-done discovery. According to the PLOS paper, expanded wildlife and veterinary surveillance is needed, in part because noninvasive fecal testing can underestimate how widespread the parasite really is. Their genetic analysis links the local findings to a strain that has been moving across North America, which the researchers say adds urgency to broader monitoring and public education to help protect both pets and people.
