New-to-Nova Scotia parasites found in coyotes

Researchers looking into parasites affecting coyotes have found two that were not previously known to be in Nova Scotia, and which could have an impact on the predator, other canines, and moose.

Jenna Priest, a masters student in biology at Acadia University, was researching known parasites affecting coyotes with the help of the province’s department of lands and forestry. That’s when French heartworm was found in a coyote carcass brought to Lands and Forestry officials.

Smaller than regular heart worm, it was the first recorded finding of the parasite in the Maritime provinces, although they have been found in red foxes and coyotes in Newfoundland.

French heartworm originated in Europe, and genetic testing in Newfoundland showed that the ones found there came directly from across the Atlantic. They likely arrived via dogs that had been travelling with their owners or were imported, Priest said.

“It’s a bad thing for coyotes, and being in a wild population it can affect our domestic dogs as well; they can actually pick it up in the woods,” Priest said.

She believes that worm treatments used by vets now will deal with the parasites should they be picked up by the family dogs.

What makes French heartworms an issue is that they are smaller, and “if infections become intense, you have larger quantity of worms blocking up the arteries in the heart,” Priest said. “It can lead to severe complications.” The common heartworm can grow to 10 to 20 cm long, but the French heartworm is only up to one centimetre in length.

That means there could be exponential growth of the parasite numbers before symptoms become apparent. Heartworms of both types can reduce and block blood flow in the heart.

Priest said its not known yet how the French heartworm arrived in Nova Scotia, but “we are collaborating with a few other biologists to see if we can get that answer.”

The eggs of the parasite are found in the feces of infected animals, which is then consumed by slugs and snails. They become intermediate hosts, and if they are eaten along with grass by a canine, the parasite spreads to another animal.

So far, it has been found in four coyotes, one each from Kings, Hants, Halifax and Lunenburg counties. About 100 in total were examined for the study.

“That tells us that it has kind of established itself in the province,” Priest said. But the fact it was only found in four indicates that “it might not necessarily be raging through the coyote population right now. I think we’ll have to wait a few years to see if it does have an impact.”

While it is one more thing that could lead to coyote mortality, she said, other variables such as harsh winters and food supply also may have an impact on numbers and have to be taken into consideration when looking at changes in the population.

During the study, researchers also found a tiny tapeworm in a single coyote in Cape Breton. That worm does not appear to have previously been known to be in the province either, with the closest reports of it being in Ontario and Quebec.

While French heartworm can’t be spread to humans, the tapeworm “is more important for human implications because humans can accidentally be infected by these parasites,” Priest said.

But while the tapeworm is usually found in the stomach, these ones will go to the lungs of humans, and form dangerous cysts that need to be surgically removed, she said.

It can only be spread by contact with feces and then food, such as scooping dog droppings and then touching food.

While the tapeworm has only been found in one coyote, Priest said there haven’t been many samples to examine in Cape Breton.

But a collaborator on the project has found the parasite in the lungs of moose. That can create a circle where the coyotes eat the lungs of the moose — or other prey animals — which put the tapeworm in the coyotes, which then drop feces that taints grass that is eaten by prey animals again.

Priest said another study is expected to follow shortly that looks at the possible impact of the tapeworm on the moose population, in conjunction with Parks Canada and Nova Scotia’s Department of Lands and Forestry