Cougar attacks on Vancouver Island may be tied to fatal deer disease

A cougar is seen in this undated image. (Shutterstock)

A disease that has been killing off deer populations in coastal B.C. over the past few years could be linked to a recent spike in cougar attacks and encounters on Vancouver Island.

The province first detected adenovirus hemorrhagic disease (AHD) in 2020, particularly near the Mid-Island communities of Duncan and Nanaimo, as well as on several Gulf Islands.

The disease causes damage to the lungs and intestines and is generally fatal for deer. However, the illness can also cause chronic ailments, such as ulcers and abscesses in a deer's mouth and throat, according to the province.

Over the past two years, the province has tested more than 100 deer for the virus, with the public reporting more than 300 dead deer to the B.C. Wildlife Health Program.

DEER AFFECTING COUGAR HABITS

A veterinarian with B.C. Wildlife believes that a wide range of deer have been impacted by the disease, leading to a decline in deer populations on Vancouver Island.

With a lower number of prey during the winter, cougars may be turning elsewhere for food.

"Predators will be looking for alternate food sources and may be a bit hungrier than they would be if there was an abundant deer population," said Caeley Thacker, a wildlife veterinarian.

"I think it's not surprising that we may be seeing more predator contact in our communities right now," she said.

There have been five reports of cougar attacks on pets in the Sooke and Metchosin areas over the past several weeks.

Thacker says AHD has not been confirmed in humans or any other animal species.

She recommends that people avoid handling or harvesting sick deer.

The province is asking anyone who spots a dead deer that may have had AHD to report it on the Wildlife Health website, where further information on symptoms can be found.

There is currently no treatment for the disease in deer.