Members of the black-tailed deer family appear to be most severely affected by adenovirus hemorrhagic disease. (Photo - Veronika Andrews)

Fast-spreading disease baffles wildlife experts

'Hundreds' of deer dropping dead on Vancouver Island

Sooke resident Susan Renaud’s Maple Avenue North property is an idyllic place for black-tailed deer, a spot where the animals come to play, rest, nibble on a handful of grass, and lick up a few drops of water.

Does have given birth three times in her backyard over the last 15 years.

But several weeks ago, Renaud came across two dead fawns in her yard – for no apparent reason. It was a devastating discovery.

“It was very upsetting. The deer to me are like pets,” Renaud said.

RELATED: Province tracks potential deadly deer virus outbreak on Gulf Islands

Among neighbours, Renaud is far from alone. Since last fall, Sooke residents and others from Vancouver Island and the Gulf Islands reported hundreds of strange deer deaths to local and provincial officials.

At first, provincial officials weren’t sure what was killing deer. They reasoned it could be anything from fertilizers to pesticides – or a virus.

But after tissue samples were sent to Canadian and United States laboratories for testing, the real culprit emerged – a fast-spreading virus in deer that operates not unlike COVID-19 does in humans.

Adenovirus hemorrhagic disease (AHD) poses no risk to humans, livestock or pets – but until now has never been recorded in B.C.

First discovered in California in 1993, the disease has gradually moved up the west coast. In 2017, about a dozen animals fell ill in Washington state. The condition began showing up in the Gulf Islands last fall.

Provincial wildlife veterinarian Caeley Thacker said the virus is “very contagious,” spread by direct contact between deer and through the air. Like COVID-19 in humans, research suggests healthy-appearing deer can shed and spread the virus.

“There’s not a whole lot known about the disease,” Thacker said.

“We know from other places it seems to be a nose-to-nose contact transmission pathway. We don’t think there are insects or anything like that involved, but, again, we don’t know.”

Visible symptoms of AHD include difficulty breathing, foaming or drooling from the mouth, diarrhea, and seizures. Other symptoms include ulcers and abscesses in the mouth and throat.

Thacker suspects “hundreds” of deer have died from the disease on Vancouver Island in less than a year but doesn’t think it can wipe out the deer population since the disease only transmits from direct contact.

Part of the problem with monitoring the disease is the only reliable diagnostic tool is collecting samples from the carcass of dead deer.

“We can’t tell until the animal is dead if it has AHD,” Thacker said.

So far, deer affected with AHD have been found between Sooke and Courtenay.

But sampling is limited due to laboratory capacity and financing.

“We’ve only been testing animals from areas that haven’t been identified, so we’re tracking the spread of the disease rather than the prevalence. The sampling is limited to new areas,” Thacker said.

The province is also collecting blood samples from live animals to see if some deer create antibodies and survive the disease.

The province asks anyone who sees deer with symptoms of AHD to report them to the Wildlife Health Laboratory at 250-751-7246.


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