The lethal rabbit hemorrhagic virus Type 2 (RHDV2) is sweeping the Southwestern United States. Detected first in New Mexico in early March, it has since killed domestic and wild rabbits as it has spread through Texas, Arizona, Colorado, Nevada and, most recently, California.
The virus is not a coronavirus and is not known to affect humans or other animals. It infects only rabbit species, including jackrabbits, hares and pikas.
Scientists think the pika, a tiny alpine mammal, may provide clues to what climate change will mean in the Rocky Mountains. Pikas, which are related to rabbits, are particularly sensitive to changes in temperature and snowpack.
According to the U.S. Department of Agriculture, infected rabbits might display symptoms including fever, lack of appetite, swelling and respiratory or nervous signs. But often the disease is not detected until the animal’s sudden death. A rabbit that has died of the virus might have blood on its nose or mouth due to internal bleeding.
It’s the first outbreak of the virus in wild rabbit populations in North America. In Southern California, where the most recent RHDV2 outbreak was reported early this month, roughly 10 dead jackrabbits were discovered on private property in Palm Springs, the California Department of Fish and Wildlife said in a news release.
The virus could significantly affect wild rabbit populations, especially species already imperiled, such as the endangered riparian brush rabbit or the pygmy rabbit, according to CDFW Senior Wildlife Veterinarian Dr. Deana Clifford.
“Unfortunately, we may also see impacts to species that depend on rabbits for food, as rabbits are a common prey species for many predators,” Clifford noted.
Concerns have also been raised about the conservation of at-risk species in other states.
The virus is highly contagious and can be transmitted via contact between infected rabbits or carcasses, through their meat or fur, through contaminated food and water, and when carried on clothing and shoes.
Rabbits can be vaccinated against the virus, but the vaccine is approved for use only in Europe. However, it can be approved for use in the U.S. when the virus circulates in feral and wild rabbits, the USDA said in an emerging risk notice. This has happened in New Mexico, which received 500 doses of the vaccine from France on Wednesday, state veterinarian Ralph Zimmerman told The Washington Post.
It’s unclear how the virus made its way to New Mexico. Matt Gompper, a disease ecologist and head of the Department of Fish, Wildlife and Conservation Ecology at New Mexico State University, told CNN he predicts it made its way over via the domestic rabbit trade or rabbit meat.
Rabbit hemorrhagic disease was first recorded in China in 1984 and is believed to have come from rabbits imported from Europe. The first variant (RHDV) spread widely across several continents. The Type 2 variant, the new RHDV2, spread in Europe after its emergence in 2010 and has occurred in Australia, but only a few small outbreaks in domestic rabbits had previously been reported in North America.
There is no cure; infected rabbits should be isolated. Authorities ask that any sightings of sick or dead rabbits be reported to state wildlife officials. Dead rabbits should not be touched or moved.
And, like people, pet rabbits should be staying at home. A USDA fact sheet says owners should introduce no new rabbits and limit any contact with outside rabbits, practice good hygiene and handwashing before and after handling, and use separate equipment for any new or sick rabbits.