A killer virus, highly contagious for domesticated rabbits, has reached the Windsor-Essex County region and at least one pet bunny has succumbed to the disease.
Professor Kenneth Ng, a University of Windsor researcher, who has been studying the virus causing rabbit hemorrhagic disease, or RHDV-2, for 30 years, said the illness causes internal bleeding, which usually leads to major organ failure.
“It’s really contagious and it has really high mortality, meaning that if the rabbit gets infected, something like 70 to 90 per cent of them die within 48 hours,” Ng said.
Melanie Coulter, executive director of the Windsor/Essex County Humane Society, said despite just one reported local case so far, rabbit owners should be cautious.
“This is something that people who love rabbits should be concerned about,” Coulter said. “I think the most important advice is to keep your pet rabbit indoors and to be really cautious with introducing them to any new rabbits.
“But there is evidence, even if your rabbit is exclusively indoors, you can bring (the virus) indoors,” she added.
“So making sure that you’re not tracking your shoes in the house and bringing in hay and vegetation from outside where it could have come in contact with the illness is important as well.”
Rabbits are the third most common adopted animal at the humane society, after dogs and cats.
Rabbit hemorrhagic disease has been a “pretty big” problem in Asia and Europe for the last 20 years, Ng said, “but it’s never gotten into North America until recently.”
The original strain of the virus, discovered by Spanish researcher Francisco Parra, didn’t infect native North American rabbits. It spread rapidly though wild and domesticated rabbit populations across Asia, Europe and Australia.
In Canada, pet rabbits and those commercially farmed, which are more than likely descendants of rabbits imported from Europe, are susceptible.
But it may not be long before wild rabbits in Canada are affected by the deadly viral disease too as the current strain of the virus is infecting wild rabbits in the southwestern United States.
“I don’t think there’s any evidence yet that it’s in wild rabbits in Ontario but it probably will eventually,” Ng said. “It’s just a matter of time.”
He and his team at the university have been studying the biochemistry or molecular function of the components in RHDV-2 for more than 20 years.
Included in that is work on other viruses, including the COVID virus as well as the norovirus that causes what most people commonly call stomach flu.
“One of the reasons we were interested in it is that this rabbit virus is so infectious, causes this horrible disease, and then there’s this human one that’s really common but doesn’t cause like nearly as bad a disease,” Ng said.
“Most people don’t die from the food poisoning (symptoms) caused by norovirus (but) because they’re similar, a lot of people have been interested.”
The rabbit hemorrhagic disease virus does not affect humans. There is a vaccine for rabbits but it is not readily available in Canada.
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Ng said once researchers understand how viruses work at the molecular level, more effective treatments and ways to manage diseases can be developed.
“You can ask, why do we study this rabbit virus because it’s rabbits?” he said. “Usually, you’re not going to give drugs to rabbits.
“The thing is, it’s related to these human viruses that also cause disease. Norovirus has kind of food poisoning symptoms that people get over but there’s no saying in the future that norovirus (couldn’t) become more virulent and cause more serious disease … kind of like (how) this COVID-19 coronavirus developed.”