Recently in Ontario, the University of Guelph Ontario Veterinary College diagnosed 4 cases of Fox Tapeworm (Echincoccus multilocularis) in pet dogs. This small tapeworm which is infective to people had not previously been seen in Southern Ontario and so it’s presence raised some alarm. Lets take a look at this emerging parasite and see what it means to you.
(Taken from the worms and germs blog; <http://www.wormsandgermsblog.com/files/2008/04/M2-Echinococcus.pdf>
- Echinococcus is a group (genus) of tapeworms. Tapeworms are parasites that live in the small intestines of many different species of animals, including humans.
- Echinococcus spp. are quite small compared to other tapeworms. For example, Echinococcus multilocularis is less than 1 cm long, whereas an adult Taenia saginata may be up to 10 metres long!
- Except for the head, a tapeworm’s body is made up entirely of small segments, called proglottids, which regularly break off from the end of the worm’s tail as it grows and contain the parasite’s eggs. Both intact proglottids and eggs may be passed in the feces.
- Of all the tapeworms in pets, Echinococcus spp. pose the greatest disease risk to people.
Like other tapeworms, Echinococcus spp. are normally transmitted between two different groups of animals: definitive hosts and intermediate hosts. A definitive host is an animal that normally carries the adult tapeworms in the intestine and sheds the eggs in its feces. For E. multilocularis, foxes and other wild canids such as coyotes and wolves are definitive hosts, and sometimes dogs. An intermediate host is an animal species that typically harbours the cyst stage of the parasite in the body tissues, and is then eaten by a definitive host. Small prey animals such as voles, mice and lemmings are common intermediate hosts for E. multilocularis, whereas E. granulosus may be found in larger animals such as rabbits, sheep and moose. People and dogs can be “accidental” intermediate hosts.
Now here is the scary part. People can develop Alveolar echinocococcis caused by E. multilocularis. With this species there are often multiple cysts that grow inside the accidental host, ranging in size from that of a sesame seed to a large melon. The cysts usually start in the liver but can form and spread elsewhere. Although the cysts grow slowly, usually for 5-15 years or more before a person becomes sick, they tend to invade nearby tissues like a cancerous tumor, making treatment very difficult.
The parasite can be detected in pets by examining stool samples. Deworming medications are used to treat infections in the intestines, but cysts can be more difficult to treat, even requiring surgical removal. Preventing infection in our pets and washing our hands, especially after handling dirt in gardens or flower beds are the most effective way to prevent infection.
If you have more questions about Fox Tapeworm or parasites in general, please feel free to contact us