What is Rabbit Hemorrhagic Disease?
Rabbit Hemorrhagic Disease (RHD) is a serious viral disease that may cause a high rate of infection and death in rabbits. It does not cause disease in humans or animals other than rabbits. It is caused by a Calicivirus, which can survive for weeks in the environment, and can be spread over short distances on objects such as articles of clothing, and therefore can be spread easily and rapidly.
Why is it significant that RHD has been found in Ohio?
The rabbit that died on Sept 19, 2018, in Medina County is the first confirmed case in the U.S., of a new strain of the virus, RHD2. The rabbits at this location were housed in horse stalls. They lived in this location for several years, and there had been no recent movement of rabbits in or out of this location.
There are several types of RHD viruses. The original types of RHD virus could infect domestic (pet) and European wild rabbits, but could not infect wild U.S. rabbits, such as cottontails. Not infecting cottontails is advantageous in limiting spread of the disease. RHD outbreaks, with original strains of the virus (not RHD2), have been reported in pet rabbits in the U.S. in 2000 (Iowa), 2001 (Utah, Illinois, New York), 2005 (Indiana), 2008 (Maryland), and 2010 (Minnesota). In these cases, only a single household or facility was involved, with no further spread. These short-lived, small outbreaks were controlled by isolation and cleaning.
The virus reported recently in Ohio is a newer strain, RHD2. This new strain is able to infect a wider variety of rabbit species, although it is not yet known if rabbits such as cottontails can be infected. The Ohio Department of Agriculture is working with state and federal agencies to conduct careful surveillance of wild rabbits in the area surrounding the confirmed case of RHD2.
What are the symptoms of RHD in rabbits?
Affected rabbits may die suddenly without symptoms, or may show neurologic signs such as incoordination, excessive excitement or convulsions prior to death. Most will appear to have difficulty breathing just before death and may have a bloody discharge from the nose. A few may have milder signs and survive. However, the death rate is very high – between 50 and 100%. In Canadian outbreaks of RHD2 in 2016 and 2018, the death rate was close to 90%.
How long does it take for a rabbit exposed to the virus to become ill?
The time from virus exposure to symptoms (incubation period) is very short, with affected rabbits showing illness or dying within 2-9 days.
How is the virus spread?
Infected rabbits pass on the virus through any body fluid, including urine, feces, or fluid from the eyes nose or mouth. The virus survives outside of the body, so it can be found on rabbit fur, bedding or anything the infected rabbit touches. The virus can live for weeks in wet organic material such as dirty bedding. It can be passed over short distances on clothing, shoes or hands. It can also be spread by flies and mosquitos. It is resistant to freezing and heat.
Surviving rabbits are immune, but can continue to pass the virus for 42 days or more.
RHD is not known to cause disease in humans or other species.
How is the virus treated?
There is no cure for RHD. Rabbits that are not severely infected may be more likely to survive with supportive care such as fluids and assisted feeding.
Can my rabbit be vaccinated to prevent this disease?
Vaccines are available in the U.S. and recommended for companion rabbits.
How can I protect my rabbit?
Since the virus can be carried on shoes, clothing, or hands, it is important to pay particular attention when coming home to your rabbit after you have visited locations where other rabbits have been. This would include pet stores, feed stores, shows, shelters, etc. To protect your rabbit:
- Change your clothes after handling or coming in contact with rabbits. Wash these clothes twice in hot water before you wear them around your rabbit.
- If you volunteer at a shelter in an area with an outbreak, wear protective clothing or a set of clothing and shoes that you wear only at the shelter. You may want to wear shoe covers or plastic bags over your shoes, secured with a rubber band. When you leave the shelter, remove and dispose of the covers before entering your car, making sure not to touch the outside of the bag. Launder these clothes separately from your other clothes in hot water twice.
- Take your shoes off, and ask your guests to take their shoes off before entering your home.
- Disinfect shoes that may have been contaminated. To do this, place the shoes in a foot bath that contains one of the following disinfectants: bleach (1:10 dilution), potassium peroxymonosulfate (Virkon), accelerated hydrogen peroxide (Prevail, Accel, Rescue wipes or solution, and Peroxigard), 2% 1-Stroke disinfectant, Parvosol, or parvoviricide disinfectant. (You may wish to speak with your veterinarian about how to obtain these products.) In order to kill the virus, shoes and any other items to be disinfected must be in contact with the disinfectant for at least ten minutes, during which time the disinfectant must remain wet. Merely spraying shoes with disinfectant and leaving them to dry is not effective.
- Know your sources of hay and feed and if they are near areas of any outbreaks.
- Minimize insects in your home by installing window and door screens. Eliminate mosquitoes and flies from your home.
- Quarantine any new rabbit for at least 10 days. Always handle quarantined rabbits last, and keep all supplies for them separate from your other rabbits’ supplies.
How can I protect other rabbits?
Following the procedures listed above to protect your own rabbit will also protect other rabbits by preventing the spread of the virus.
If you have a rabbit die suddenly, or die after demonstrating symptoms such as seizures, incoordination, difficulty breathing or a bloody discharge from the nose, it is essential that you not bury the remains. The virus can live in the remains for months and can become a source of infection to wild rabbits. Please contact your rabbit’s veterinarian prior to taking them in for a diagnosis, or contact the Ohio Department of Agriculture.