Biologists vaccinate Washington’s endangered pygmy rabbits to protect them from ‘bunny ebola’
A highly contagious, often fatal virus is threatening Washington’s endangered pygmy rabbits. Biologists want to vaccinate the palm-sized rabbits before the virus crosses the state’s borders.
Under bright moonlight, with the help of a spotlight-like flashlight, Paula Clements scanned the hip-high sagebrush for a reflective orange flag, which marked the site of a pygmy rabbit burrow.
“See that orange flag right in front of us? If I had it sitting on top of a taller bush, we probably would have been able to see it a while ago,” said Clements, a technician with the Washington Department of Fish and Wildlife.
Somewhere out in the dark, pygmy rabbits had left their burrows to feast on sagebrush leaves in the vast expanse of Washington’s Sagebrush Flat Wildlife Area, near Ephrata. Clements took advantage of the rabbit’s time away from home.
She placed a tomahawk trap directly in the fist-sized entrance of the pygmy rabbit burrow, camouflaging it by tucking a strip of burlap around the cage.
“When the rabbit hops in, it pushes down on this trip plate, and then it releases this little latch, and the door shuts. That’s where they hang out, until we come and get them,” Clements said.
She spotted signs of the tiny rabbits all around this burrow, including a nearby pygmy rabbit trail and fresh scat.
She said she hoped the signs signaled good luck in a week that was anything but lucky. Over two days, the team had caught only one rabbit.
Pygmy rabbits are the smallest rabbit species in North America. An adult rabbit can grow up to 12 inches long and weigh around a pound.
Any rabbit caught in the trap would face an unusual morning. A shot from a tiny needle right in its haunches, all in the hope of saving this endangered population from Rabbit Hemorrhagic Disease Virus, an encroaching, fatal virus.
“The virus is on Washington’s doorstep,” said Jon Gallie, a wildlife biologist with the Washington Department of Fish and Wildlife.
One day, it will show up, he said.
The virus, often called bunny ebola, is thought to kill 80 to 90 percent of rabbits just days after the initial infection. The virus is believed to infect only rabbits, including pets and feral rabbits. However, biologists are concerned the virus could infect pikas, which while not endangered are in peril, Gallie said.
In an eerie parallel to Covid-19, Rabbit Hemorrhagic Disease Virus first ramped up in the spring of 2020, starting in the Southwest. The virus leapt around the West with sickening speed, Gallie said. The virus has now been found in every western and southwestern state except Washington.
Two weeks ago, biologists in Nevada confirmed a group of pygmy rabbits they were tracking died of the virus, marking the first known time pygmy rabbits died in this outbreak. The Nevada biologists haven’t trapped a pygmy rabbit since, Gallie said.
In the Northwest, officials have confirmed the virus in Oregon and Idaho.
The virus first showed up in Oregon in March 2021, infecting a group of feral rabbits near Portland. In April, a wild black-tailed jackrabbit died in southeastern Oregon’s Malheur County. A month later a second wild black-tailed jackrabbit died in south-central Oregon’s Lake County. Most recently, the Oregon Veterinary Diagnostic Laboratory confirmed another case in a wild rabbit in Central Oregon’s Crook County.
According to the U.S. Department of Agriculture, another wild rabbit died of the virus on March 20 in southeastern Oregon’s Harney County.
The Oregon Department of Fish and Wildlife asks people to keep an eye out for the disease and to report any suspicious rabbit deaths.
To report wild rabbit mortalities, people can call the wildlife health reporting hotline at 1-866-968-2600 or e-mail email@example.com. To report sick or dead domestic or feral rabbits, people can call the Oregon Department of Agriculture at 1-800-347-7028.
In Idaho, wild jackrabbits south of the Boise Airport died of the virus.
To report a suspicious rabbit, people can call the Idaho Fish and Game’s wildlife health laboratory at (208) 939-9171 or can report the sighting online.
Virus particles can travel on most any material, Gallie said, from people’s boots to weeds to other scavenging wildlife or even on insects.
“It's a pretty hardy virus, and it's able to spread very easily. So that's one of the hard things. People could come here to visit and spread it and not know it,” Gallie said.
Detecting the virus is a challenge as well, he said.
To help protect Washington’s pygmy rabbits, Gallie and his team ordered the vaccine from a manufacturer in Europe.
“We're just lucky, period, that there is a vaccine,” he said.
Since 2020, the Washington team has vaccinated around 100 pygmy rabbits.
“In an endangered population, where we may only have 150 left in existence, we can't sustain that,” he said, although he said an exact population estimate is difficult.
Washington’s Columbia Basin pygmy rabbits have been geographically isolated from other populations for at least 10,000 years. Reintroduction efforts brought the rabbits back to two areas in the region – Sagebrush Flat and Beezley Hills near Quincy. The most recent and most successful population, near Jameson Lake, all burned in the 2020 Pearl Hill Fire, a loss that still stings biologists.
The tiny rabbits face a litany of threats from wildfires, habitat loss, climate change, and a variety of predators, including raptors and weasels. It’s hard to be a prey species, Gallie said.
A severely contagious virus could erase decades of work to help this species.
So, the team quickly got to preventative care, working on one of two projects vaccinating wild rabbits in North America. The first project, in an active outbreak in central California, began vaccinating its endangered riparian brush rabbits shortly before Washington biologists.
Once the team traps a rabbit, veterinary technician Angel McCormick gets to work. As one of three people in the state qualified to vaccinate these rabbits, McCormick’s hands are integral to the team.
“The rabbits have paper-thin skin, and the syringes that we’re using are very tiny,” McCormick said.
To give the shot, someone must calmly hold the rabbit in a specific position, she said. The team covers the rabbits eyes to make them less nervous.
Rabbits must be more than 10 weeks old for the shot to work properly. It takes two weeks for rabbits to receive the full protection of the vaccine, which lasts about a year or just about the lifetime of a pygmy rabbit in the wild.
“Proportionally to the rabbit, it would be like us getting a 12-ounce Gatorade shot in our haunches,” Gallie said of the size of the shot.
After the shot, the team takes a DNA sample from the rabbit’s ear. That also helps identify which rabbits already received the jab, if the team recaptures the rabbit.
Then, McCormick closely monitors each rabbit while it's still in a crate for side effects, including fevers or short-lived neurological problems. So far, she said, no rabbits have suffered severe side effects, although a couple had mild reactions.
“They’ll look lethargic in their little crate. The worst thing that can happen is they can become overheated,” McCormick said, in which case she applies an ice pack to the bottom of the crate to bring the fever down.
Although the vaccine supply is limited, Clements said the team hasn’t run out yet.
“I guess that also speaks to the level of endangeredness,” Clements said of Washington’s small number of rabbits.
That level of endangeredness was on full display at Sagebrush Flat each time the team checked the 15 traps.
Clements checked the door of each trap she set.
“Open. Open. Ugh!” she sighed heavily, frustrated.
“You can see that they’ve been here, though. Not long ago. There are the darker pellets, which means they’re fresh,” Clements said as she pointed to fresh scat.
This is the first time the researchers have attempted to trap pygmy rabbits in the spring. They’d hoped to catch the rabbits during breeding season, when one study showed mother rabbits could pass partial immunity to their offspring.
The team wondered: Is the timing off? Would it work better to trap at night? Have the mother rabbits hunkered down, pregnant already? Might the rabbits sense people and simply move to a different burrow for the day? Or are the rabbits just not in their burrows right now?
“Sometimes it feels like we’re Elmer Fudd, where it’s like, ‘Be very, very quiet. We’re hunting wabbits,’ except we’re not hunting. Just trying to catch them. Just trying to save an endangered species out here,” Clements said.
An endangered species that is very hard to find.
“It's pretty difficult when you consider how small they are and how easy it is to miss their sign,” Gallie said. “They only live in a couple burrows the size of a softball or volleyball. Easy to walk by. You can't just drive by road and go, ‘Oh, there’s a pygmy rabbit out there.’”
Gallie said he planned to change the strategy the following week to trap at different times of the day. No more 4 a.m. starts.
The team is on this mission for the long haul, he said. Biologists will continue to trap and vaccinate rabbits, including a big effort this summer, when they can vaccinate easier-to-trap juvenile rabbits to stave off this virus.
“We can only handle so many biblical plagues,” Gallie said, of the encroaching Rabbit Hemorrhagic Disease Virus.