Echinococcus multilocularis is causing increasing concern in Ontario lately (amongst the few people who are aware of it, at least) as there’s evidence that it may have become established in the province. This parasite is a tapeworm harboured by canids (including both domestic dogs and wild ones like coyotes and foxes), and can cause serious disease in people. It’s an insidious problem since the incubation period in humans is many years, meaning it takes a long to realize that there’s a problem.
We don’t know the status of this parasite in the province but there’s enough evidence to be concerned and look into the issue further.
If you want to learn more about it, Dr. Andrew Peregrine’s recent seminar on the topic is a great start.