Wild and domestic rabbits across the country are dealing with a deadly and highly contagious viral illness that can kill up to 80% of victims. Known as rabbit hemorrhagic disease, cases of a relatively new type of the illness have been spotted in over a dozen different states since 2020. Officials are warning bunny owners to keep them indoors, to get them vaccinated if possible, and to report any sick or dying rabbits suspected of having the virus.
The disease is caused by the rabbit hemorrhagic disease virus (RHDV), a cottonball-shaped member of the genus Lagovirus. It’s not harmful to humans, but it can gravely affect European rabbits, as well as cottontails and hares. The highly contagious virus can be transmitted through direct contact as well as through contact with contaminated surfaces and even insect bites. Once inside the rabbit, it tends to attack the liver, causing hepatitis, which is characterised by fever, weight loss, and jaundice. It can then cause liver failure and more dire symptoms like convulsions, heart murmurs, and profuse bleeding, or the titular haemorrhaging.
The classic version of RHDV only affects European rabbits, and while it has become established across much of Europe and Asia, it hasn’t become common in the U.S. In 2010, however, a new strain of the virus, now called RHDV-2, was discovered and began spreading like wildfire. RHDV-2 can affect a wider range of rabbits, and it has gained a foothold in the U.S. and other countries outside of Europe. It was originally thought to be less deadly than other forms of the virus, but its mortality rate may have increased recently.
This week, wildlife officials in Kentucky reported that two pet rabbits had recently contracted and died from RHDV-2. Earlier this month, Oregon officials reported further sightings of the virus, with the latest case in mid-December, while a case was found in New York last month as well. In an update released by the Florida Department of Agriculture and Consumer Services this week, officials noted that RHDV-2 has been found in 18 states, including Florida. The state has found two cases, with the latest in October 2021, both involving domestic pets.
Though outbreaks of RHDV can be seasonal, the virus can endure harsh environmental conditions like the freezing cold for up to three months or linger in the bodies of rabbits that die from it. Rabbits who survive their illness can also remain contagious for weeks or even months. So officials and experts are recommending that pet bunnies stay indoors and avoid contact with new bunnies, especially if brought in from other states. Hunters, too, are being asked to take precautions, such as not hunting in areas where they see sick and diseased rabbits or where outbreaks have been reported, and to wash their hands after hunting before touching pet rabbits.
There has been an available RHDV vaccine for the older forms of the virus for some time, but these don’t appear to protect bunnies from RHDV-2. A more recent experimental RVDV-2 vaccine is now available in the U.S., though, and some affected states like Florida are distributing it via veterinarians’ offices.