A parasitic tapeworm linked to a potentially lethal disease has been detected in West Coast wildlife for the first time, raising concerns about its spread among coyotes near Puget Sound.
A parasitic tapeworm known as Echinococcus multilocularis, commonly referred to as the “fox tapeworm,” has been identified in West Coast wildlife for the first time. Researchers from the University of Washington discovered the parasite in 37 out of 100 coyotes sampled near Puget Sound in Washington State. Their findings were published in the journal PLOS Neglected Tropical Diseases earlier this year.
Despite the detection of the parasite in wildlife, researchers emphasize that this does not indicate a high risk of human infections, and the overall threat to the general public remains low.
“The reason that [cases are] so high in coyotes is because they are regularly eating raw rodents, and that is the primary way for them to get infected,” said Yasmine Hentati, the lead author of the study and a recent graduate with a doctorate in environmental and forest science. She made these remarks in a press release.
The study’s genetic testing revealed that the coyotes carried a newer, more infectious European variant of the tapeworm, which has become the predominant strain in the United States and Canada. Prior to the 2010s, Echinococcus multilocularis was extremely rare in North America, with cases largely confined to remote islands in Alaska. However, over the past 15 years, the parasite has expanded its range, with increasing dog and human infections reported across the Midwestern U.S. and Canada.
According to Dr. Linda Yancey, an infectious disease specialist at Memorial Hermann in Houston, cases in coyotes have been spreading westward from the upper Midwest for several years. Infected animals have now been found on the West Coast. While some cases exist in Eastern Europe, the infection is rarely seen in the United States, Yancey noted.
Most cases of echinococcosis are diagnosed in individuals who have immigrated from or traveled to regions such as Central and East Asia, the Middle East, and North Africa. “Worldwide, the area with the highest prevalence of human infections with the fox tapeworm is western China,” Yancey added.
The tapeworm is transmitted among wild canids, primarily cycling between foxes and rodents. Humans can become infected by accidentally ingesting worm eggs, which can occur after handling contaminated soil or consuming contaminated food. Infection can also happen through contact with a pet carrying the tapeworm, followed by touching the mouth.
The hallmark of echinococcosis is the formation of fluid-filled sacs, or cysts, that typically develop in the liver but can spread to other parts of the body. These cysts contain thousands of immature tapeworms. The infection often goes undetected for years, as the cysts grow at a slow rate.
There are two main forms of the illness: cystic echinococcosis and alveolar echinococcosis. In cystic echinococcosis, cysts usually develop in the liver and lungs. The body responds by forming a protective wall around them, allowing the cysts to grow slowly over time. Symptoms may include abdominal pain or increased belly size if the liver is affected, or coughing and shortness of breath if the lungs are involved. These symptoms typically do not appear until the cysts grow large enough to exert pressure on healthy organs and tissues.
The infection becomes particularly dangerous when a cyst ruptures, often due to trauma, which can release cyst fluid into the body and potentially lead to death.
Alveolar echinococcosis is a rarer and more lethal form of the infection. It develops into a tumor-like mass that invades and destroys surrounding tissue, primarily in the liver, but it can also spread to other areas, including the brain. In severe cases, this form of the infection can result in liver failure and death.
Symptoms of liver failure may include fatigue, jaundice (yellowing of the skin and eyes), and abdominal pain. Yancey cautioned that this form of the infection can mimic cancer, making it crucial for individuals to consult a doctor if they notice any concerning symptoms.
While the overall risk of infection remains low, simple precautions can help reduce exposure. “The most important way to protect yourself from the fox tapeworm is also the simplest: good hand hygiene,” Yancey advised. She recommends washing hands before eating and after spending time outdoors or handling soil in areas where the tapeworm is known to exist.
For dog owners, it is essential to prevent pets from eating wild rodents and to ensure that all pets receive routine veterinary care. The Centers for Disease Control and Prevention (CDC) also advises avoiding contact with wild animals that may carry the tapeworm, such as foxes, coyotes, and stray dogs.
Regular testing and treatment for worms of all kinds can help keep pets healthy and reduce the risk of transmission to humans. Fox News Digital reached out to the lead authors of the study for additional comments.
According to Fox News, ongoing research and monitoring will be crucial in understanding the spread of this parasite and its potential impact on both wildlife and human health.