Alberta monitoring wild and feral rabbits for signs of 'fast and fatal' viral disease

Provincial investigators are closely watching for signs of any new outbreaks of a highly infectious and deadly disease that has decimated feral rabbit colonies in Edmonton and Calgary.

Rabbit haemorrhagic disease is a sudden, highly contagious and fatal viral disease that infects wild and domestic European rabbits, including most breeds that are preferred as household pets. 

The virus is almost always fatal for European rabbits, including domesticated breeds.

However, the RHDV-2 strain currently circulating affects both domestic and wild rabbits.

Wildlife experts are watching for possible spread from feral populations of domesticated bunnies to Alberta's native species of rabbits and hares. 

The virus spreads quickly through a colony, causing organ damage and internal bleeding.

The virus has a mortality rate of between 70 and 100 per cent with most infected rabbits dying within a matter of days. Many times, the only signs of infection are sudden death and blood-stained noses. 

The Canadian Food Inspection Agency said infected rabbits usually show symptoms within one to five days. 

"Death is common after a short period of illness. Death may also occur suddenly without signs," says the CFIA. 

The disease rapidly "burns through" an infected colony, said Margo Pybus, a wildlife disease specialist with Alberta Fish and Wildlife and a University of Alberta professor. 

"It's so deadly for the European rabbits and hares," she said. "Basically all of the feral rabbits, the domestic rabbits, disappear from the area."

While the risk is considered minimal among wild species, there is a chance it could spread into native species of rabbits and hares, Pybus said. 

Pybus expects that the virus will kill colonies of feral rabbits so quickly that it won't have the opportunity to proliferate through native species like hares and jackrabbits.

In Edmonton in the fall of 2021, the virus killed a colony of about 30 rabbits that had lived in Holy Cross Cemetery for more than three decades.