Last year, experts with the University of Alberta warned of a dangerous tapeworm found in at least five people in recent years (Listen to the interview below). The parasite is called Echinococcus multilocularis (EM) and according to the University of Guelph, this same parasite has been reported in five dogs in Southern Ontario since 2012.

Reports of the disease that EM causes, called alveolar echinococcosis, surprised University of Guelph PhD candidate, Jonathon Kotwa, and Prof. Andrew Peregrine from the Department of Pathobiology, who have been studying the tapeworm in wild animal populations.

Ontario map/public domain wikimedia commons
Ontario map/public domain wikimedia commons

When left untreated, alveolar echinococcosis is potentially fatal in humans and dogs. Until recently, EM was not legally reportable in Canada, making it almost impossible to track animal or human cases. But the findings of this research have helped successfully push for the disease to become reportable in animals in Ontario.

“We are working towards better awareness of this infection. EM can have serious physical health, mental health and economic impacts – we hope to limit this by describing the previously unknown distribution of this infection in Ontario,”  says Kotwa.

Alveolar echinococcosis involves the liver, but can affect other organs as well. The intermediate stage of the parasite grows slowly and often goes undetected for a lengthy period because the liver can function normally until it is extremely damaged.

According to UAlberta infectious diseases expert, Stan Houston, in most cases, the early presence of Echinococcus multilocularis infestation is symptomless.

“Roughly one-third of patients who are diagnosed are jaundiced (turn yellow). Another third report unspecified pain and see a doctor for that reason. The other third will visit a doctor for another reason and through an ultrasound or CT scan, a liver mass is identified.”

Because the parasite is initially symptomless and may be left to slowly grow, by the time it is found, about two-thirds of patients will be inoperable.

“They can survive the parasite with lifelong anti-parasitic medicine. If it is entirely removed surgically, patients usually only need to be on the medicines for two years,” added Houston.

If left untreated, the parasite will kill its human host in 10 to 15 years.

The parasite is passed to wild canids, such as foxes and coyotes, by eating rodents that are infected with the larval (intermediate) stage of EM. The researchers found that roughly 25 per cent of wild canids tested from across southern Ontario were positive for EM; infected wild canids carry the adult tapeworms in their small intestine and shed eggs in their feces. Humans and dogs can potentially develop alveolar echinococcosis when these eggs are accidently ingested.

Dogs can develop two different kinds of EM infections. Like foxes and coyotes, dogs can also become infected with the adult tapeworms and shed infective eggs in their feces – dogs that hunt rodents are at an increased risk of developing such an infection. While an infection with the adult stage is harmless to dogs, the eggs shed in their feces are a risk for humans developing alveolar echinococcosis. Furthermore, dogs that ingest large number of eggs may develop alveolar echinococcosis.

If you live in an area where Echinococcus multilocularis is found in rodents and wild canines, take the following precautions to avoid infection:

  • Don’t touch a fox, coyote, or other wild canine, dead or alive, unless you are wearing gloves. Hunters and trappers should use plastic gloves to avoid exposure.
  • Don’t keep wild animals, especially wild canines, as pets or encourage them to come close to your home.
  • Don’t allow your dogs and cats to wander freely or to capture and eat rodents.
  • If you think that your pet may have eaten rodents, consult your veterinarian about possible preventive treatments.
  • Wash your hands with soap and warm water after handling dogs or cats, and before handling food.
  • Teach children the importance of washing hands to prevent infection.
  • Do not collect or eat wild fruits or vegetables picked directly from the ground. All wild-picked foods should be washed carefully or cooked before eating.