Experts are sounding the alarm about a disease-causing tapeworm spreading across the US.
Echinococcus multilocularis (E multilocularis), also known as the fox tapeworm, mostly lives in wild animals like foxes. However, it can spread if animals or people come into contact with the tapeworm’s eggs, which are present in the feces of those infected.
The parasite enters the body and then multiplies in the liver. In humans, the fox tapeworm can cause an extremely rare liver-related infection known as alveolar echinococcosis (AE) that can lead to liver failure and death.
Left untreated, AE kills up to 90 percent of patients.
E multilocularis has long been recognized as a public health threat in Europe and Asia. It’s rare in the US but been identified in a handful of animal cases in select states such as North Dakota, Ohio, Alaska, Virginia and Pennsylvania.
However, a new study from the University of Washington is the first to detect E multilocularis in Washington state coyotes. Of 100 coyotes surveyed in the Puget Sound region, 37 were found to have the tapeworm.
It is the first time coyotes in the state have been found to have the tapeworm. Only seven previous reports have been identified in the entire Pacific Northwest, all of which were in domestic dogs.
The researchers warn that while cases in humans are extremely rare, the study shows E multilocularis may be spreading nationwide.
The tapeworm mostly lives in wild animals like foxes but can spread if animals or people come into contact with the tapeworm’s eggs, which are present in the feces of those infected
‘This parasite is concerning because it has been spreading across North America. There have been numerous cases of dogs getting sick, and a handful of people have also picked up the tapeworm,’ Yasmin Hentati, lead study author and University of Washington doctoral graduate, said.
‘The fact that we found it here in one-third of our coyotes was surprising, because it wasn’t found anywhere in the Pacific Northwest until earlier this year.’
The disease is not reportable in the US, which makes it difficult to track and monitor the true prevalence.
It’s unclear exactly why prevalence may be rising, but experts have noted climate change may have expanded or changed animal habitats, causing coyotes and foxes to interact with more varieties of species.
More transmissible strains may also be spreading.
The study authors explained that canids such as coyotes can host thousands of parasites in their intestines without becoming ill, as the worms shed eggs that pass in the feces.
Rodents, however, can become infected by eating food contaminated with coyote feces. Once consumed, parasite eggs migrate to the liver and form cysts that kill rodents. When coyotes prey upon infected rodents, the parasite’s life cycle begins again.
Humans and domestic dogs are considered accidental hosts. Accidentally ingesting tapeworm eggs often through contaminated food, water or soil, or through direct contact with infected animals can help the parasite enter the human body and begin spreading infection.
Symptoms in humans may not appear for five to 15 years after exposure, the study authors note, which can make the tapeworm difficult to detect.
The above CDC graph shows an increase in AE cases over time as the parasite spreads to different areas of the US
AE causes parasitic tumors, primarily in the liver, that can spread to other organs like the lungs and brain in humans. The tapeworm is pictured in the above stock image
AE causes parasitic tumors, primarily in the liver, that can spread to other organs like the lungs and brain in humans.
While the parasite doesn’t fully mature into cysts, it invades and destroys tissue, leading to liver failure and death.
Symptoms include abdominal pain, jaundice, weight loss and weakness.
According to the CDC, people at high risk include ‘trappers, hunters, veterinarians, or others who have contact with wild foxes, or coyotes, or their stool, or household dogs and cats that have the opportunity to eat wild rodents infected with AE’.
The agency also recommends washing and cooking wild-picked foods carefully, keeping pets away from wild animals and their feces as well as maintaining good hand hygiene, especially after contact with animals.
‘To minimize the risk of dogs getting infected with E multilocularis, owners should not let them prey on rodents or scavenge their carcasses,’ Guilherme Verocai, study co-author and an associate professor and director of the Parasitology Diagnostic Laboratory at the Texas A&M University College of Veterinary Medicine and Biomedical Sciences, said.
He also urged dog owners to give pets preventative worm and tick medications and take them to the vet regularly for routine parasite testing.
