Virus to Blame for Deer Foaming at the Mouth, Dropping Dead in the San Juan Islands


An overwhelming "cadaverine" stench hung in the air on Aimee Beveridge's wooded, 10-acre property on Orcas Island, a destination better known for salty sea scents or its fragrant firs.

"I've got another one to go find," Beveridge said with a sigh during an interview Friday. "I can smell something dead in the woods and I'm going to hunt it out and bury it."

It was the third deer in as many weeks that had turned up dead near Beveridge's home on the picturesque island about 70 miles northwest of downtown Seattle, known for its whale-watching and sailboating.

Among neighbors, Beveridge is far from alone. Since early May, residents of the San Juan Islands reported dozens of strange deer deaths to state and local officials.

"We just started getting calls of numerous deer dying for no apparent reason, with foam coming out of their mouth," said San Juan County Sheriff Ron Krebs.

At first, county officials suspected fertilizers and pesticides, warning residents in a news release to "use care and apply chemicals as directed."

But after state officials sent tissue samples to a Washington State University laboratory for testing, the real culprit emerged — a fast-spreading virus in deer that operates not unlike COVID-19 does in humans.

A Washington Department of Fish and Wildlife veterinarian said the disease, called adenovirus hemorrhagic disease, poses no risk to humans, but also that the infection could soon spread to the mainland and carve out a permanent home in  the state.

Virus's origin still a mystery

First discovered in California in 1993, the disease had been seen in Washington just once before this year. In 2017, about a dozen animals fell ill near Goldendale in Klickitat County.

Last fall, the virus unexpectedly emerged up north.

"We were surprised as anyone else when it showed up in the Gulf Islands of British Columbia. It was a long distance from the last known outbreaks," said Dr. Kristin Mansfield, a state wildlife veterinarian.

Mansfield 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.

In deer that get sick, the virus "causes the blood vessels to become very leaky," Mansfield said. Their lungs can fill with fluid or intestines hemorrhage. There is no treatment or cure.

Common signs of infection include bloody diarrhea or frothing at the mouth.

"It's a horrible way to die for these poor deer," Mansfield said.

She said it's likely the San Juan Islands became the outbreak's epicenter in Washington because of a deer swimming from island to island.

Just a few miles separate the San Juan Islands and the Gulf Islands off Vancouver Island.

Mansfield said fecal transmission could be possible also, meaning the virus could have been tracked from place to place by deer poop on tires or boots. It's also possible scavengers feeding on carcasses or parasitic insects could be spreading the virus across the islands.

The Washington Animal Disease Diagnostic Lab  confirmed two cases in San Juan County using PCR molecular testing — the technology used to confirm cases of the coronavirus  — and genomic sequencing.

San Juan County residents have submitted s of afflicted deer to state wildlife officials. Although the cause remains unconfirmed, most are likely the virus, Mansfield said. No evidence suggests the virus has jumped to other parts of Washington state — yet.

"So far, we haven't received suspicious reports from the mainland, though I would not be at all surprised if we do," Mansfield said.

Islands particularly susceptible

The San Juan Islands — where deer are plentiful and have few, if any, natural predators — could be particularly susceptible to this kind of contagion.

"Deer up here are like people's pets," Krebs said, adding that residents feed them despite his office's warnings against such practices.

In some areas, the creatures are shaping the landscape. Beveridge said her property is dotted with oxeye daisies simply because deer leave those plants alone and chew through everything else.

Avoid feeding deer, Mansfield said. It might draw the animals together and spread the virus. They could use some social distance right now.

Mansfield said residents who find a dead deer should report it to state wildlife officials using the agency's online disease reporting system, then either leave the corpse alone, pull it into the woods to decompose, or better yet, bury it. Wear gloves when handling dead animals, Mansfield advises.

Given the experience of other states that have dealt with this disease, Mansfield does not expect the outbreak to significantly alter deer populations.  The virus often preys on fawns, and many are unlikely to survive their first year of life regardless of whether they catch the disease.

Still, Mansfield said Washingtonians can expect to see more of this disease in deer.

"Now that we have it diagnosed in two areas of Washington, we're probably going to see it crop up here and there," Mansfield said.