Rabbit hemorrhagic disease in Canmore prompts worry for pikas, wild hares

A strain of rabbit hemorrhagic disease (RHD) that's been confirmed in Canmore has Alberta and Parks Canada officials on alert over concerns the disease, typically associated with domestic rabbits, could spread to their wild cousins, including pika. 

RHD first showed up in Edmonton back in 2021; this summer it was also identified in Calgary and now has been confirmed in Canmore's feral bunny population. 

According to federal experts, signs of the virus include shortness of breath, groaning, fever, loss of appetite, blood spots in the eyes, bloody noses and even neurological signs, like difficulty walking, seizures and paralysis. 

Canmore residents began writing on social media about a lack of rabbits, or even rabbit carcasses, on their normal neighbourhood walks in mid-November. Then the town's manager of protective services, Caitlin Miller, said a carcass sent to the University of Calgary for testing returned a positive result for RHD in December. 

"Anecdotally, there are far fewer rabbits around," Miller said. "It would be a good thing if we did not have a feral rabbit problem in town … we'll have to wait until at least the fall to understand what the impact of the population has been."

The Town of Canmore has spent $600,000 over the years to try and manage its feral rabbit problem. During the winter months, a private contractor combs the town to find the non-native rabbits, trapping and euthanizing them. 

Miller said this isn't the year to let up, and are asking residents who suspect they have a feral rabbit on their property to fill out forms, allowing workers to come onto private property. 

So far, there's only been one feral rabbit found when typically by this time, Miller said, there are more than a dozen sightings and some trappings. Crews are waiting for a snowfall to better track any remaining population. 

Province has been tracking the virus since 2020

The province first took note of the virus in 2020 when it began appearing in western parts of the U.S.

Typically, the disease impacts European, non-native rabbit species that are kept as pets, but has made the move to local feral populations. 

"It is deadly for these feral rabbit populations and, wherever the virus occurs, the rabbits literally all die and very quickly," said provincial wildlife disease specialist Margo Pybus. 

The RHD identified in Canmore and Calgary is a mutated strain that Pybus said could infect wild lagomorphs, which includes hares, rabbits and pikas, a small, herbivorous mammal found in mountain regions.

"In the U.S., they've identified it in black-tailed jackrabbits and a few different species of cottontails," Pybus said. "Certainly our concern in Alberta is if this virus ever was to spill over into our snowshoe hare populations … and possibly even if it got into the mountains." 

Concern for other lagomorph species

She said in Calgary there was a case where one mountain cottontail, a wild native rabbit species, died of the virus. But Pybus said that was because it was intermingled with the feral rabbits dying of the disease at the same time. 

"If we were to lose significant numbers of hares and jackrabbits, then all of the key roles that those animals play in the ecosystem are going to be affected," Pybus said. "They manage the vegetation ... and they also are at the bottom of the food chain." 

This is something Parks Canada is keeping a close eye on. 

"Concern exists for all lagomorph species found in Banff National Park, including snowshoe hares and pikas," read a statement from a Parks Canada spokesperson.

To date, there haven't been any cases identified in Banff National Park. 

So far, when the disease does spill over into native species populations, Pybus said it is less fatal than when it hits European rabbits. 

"There's always the possibility that it could mutate yet again and become something that was more lethal in the wild populations," Pybus said. "That's another reason why we're kind of tracking things … so that we can monitor the genetic makeup of this virus."

There is no cure for RHD so all the province can do to help, Pybus said, is monitor the situation and keep pet owners educated on how to stop the spread.