Echinococcus multilocularis

While some species of tapeworms have been around Ontario for decades, there is, unfortunately, a new parasite that has migrated to Ontario in recent years. This tapeworm is causing concern as while its preferred host includes wolves and coyotes. It can also affect not only our household pets but humans as well.

The tapeworm is called Echinococcus multilocularis and with its long name comes a longer life cycle, with many players involved. First, the eggs are shed in the feces of wolves, coyotes, foxes or another wild canid. The eggs are then subsequently ingested by a small rodent, like a mouse or rat. The small rodent then develops a cyst in their body. A canid will then come along and eat the rodent (along with the parasitic cyst), and at that point, the tapeworm will mature and in turn shed eggs to be passed in the feces.

While this parasite might not sound like a concern to us as pet owners, unfortunately, there is more to it. There are two ways that our pets can be impacted by this parasite. The first is if our dog or cat eats an effected rodent, they can take the place of the canid and become a host for this parasite. They will then begin to shed eggs in their feces.

The second way our pets can be impacted is if they happen to eat an egg shed in feces. They will then take the place of the intermediate host, and the parasitic cyst will develop.

In humans, the cyst typically develops on the liver, causing hepatic failure. The time between ingesting the egg and the cyst becoming symptomatic is typically anywhere from 5-10 years, but once diagnosed, it has done irreversible damage to the liver.

It is important to limit contact with coyote, fox and wolf feces as best as possible to reduce transmission of this concerning parasite. If you have a dog that is known to eat unknown feces, regular deworming is recommended.

Written by: Zoe, RVT