Endangered riparian brush rabbit survived floods and is now fighting a deadly virus with help from biologists

The riparian brush rabbit was once thought extinct, but a small population still makes its home in California’s Central Valley.

Conservation efforts helped rebuild the species, but when a highly contagious virus deadly to rabbits began sweeping through the region last year, it prompted a frantic effort to once again intervene to protect the species.

The rabbit hemorrhagic disease virus serotype-2 (RHDV-2) has been detected in domestic rabbits with a 90 per cent fatality rate, but this was a first time it has been picked up in the wild — something the U.S. Fish and Wildlife Service called “alarming.”

“Before March [2020], the biggest threat to the rabbits was winter flooding, but the virus poses an unexpected and potentially catastrophic threat,” the USFWS said.

Adult riparian brush rabbit. Photo: Don Cool/USFWS

Work began in the San Joaquin River National Wildlife Refuge to trap and vaccinate them against the virus, since the wild animals have no known immunity.

“We needed to capture some of the riparian brush rabbits on the refuge and bring them into captivity temporarily while the safety of a vaccine was determined,” Eric Hopson, assistant refuge manager at the wildlife refuge, explained.

The small cottontail, which only grows to 12 inches long and perhaps 1-and-a-half pounds, is one of the most endangered species in California.

Experts have been seriously working to protect habitat to rebuilding the population for the past 20 years.

Last August, 20 brush rabbits were caught and moved to a bio-secure area at the Oakland Zoo where they were cared for and assessed for vaccines. Then, trapping and vaccinating of wild rabbits began.

More than 200 were vaccinated in just three months.

Meanwhile, the progression of the virus seemed to slow down giving researchers — and the rabbits a break.

By late last year, the rabbits taken to the zoo were released back at the refuge.

But the work to save the species done yet.

This spring, experts set out to find out of antibodies from those vaccines are present.

Rabbits were once again trapped and blood samples taken.

This is a juvenile riparian brush rabbit. Photo: USFWS

And more rabbits were vaccinated.

No matter how small, biologist aren’t willing to give up on the riparian brush rabbit.

Efforts of the last two decades is being heralded as a success story and one of the refuge’s “greatest accomplishments.”

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Recovering newspaper reporter.

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