Rabbit Hemorrhagic Disease (RHD) is a fatal disease caused by a calicivirus that affects only rabbits. USDA considers RHD a foreign animal disease and has recently detected the Rabbit Hemorrhagic Disease Virus Serotype 2 (RHDV2) in North America. RHDV2 is not known to pose health risks to humans, livestock, or pets other than rabbits. The first detected case of RHDV2 was in Washington state in February 2018. Ohio saw a case in September 2018 and again in Washington in July 2019. Until March 2020, it was believed that RHDV2 only affected rabbits of the European species, but confirmed cases in the Southwest U.S. indicate it is affecting Eastern cottontail rabbits, the most common species in the U.S. (Hreiz, 2020).
What are the signs and symptoms?
Visual signs owners might see are swelling, bleeding in the eyes, lethargy, decreased appetite,difficulty breathing, or yellowing of the skin. Bleeding from the nose, anus, or vent are also signs of possible RHD infection in rabbits. The virus attacks rapidly, so most owners might only find dead rabbits that display bleeding from the nose, anus or vent.
How is RHDV2 transmitted?
The virus can be transmitted by contact with infected rabbits (live or carcasses) and is present in all excretions and secretions from infected animals (USDA APHIS, 2019). It can be transmitted by indirect contact with exposed objects like feeders, water crocks, cages, carriers, etc. Rodents, insects, birds, and other animals can serve as the mechanical vector for transfer to rabbits or equipment. Humans can also transmit the virus on shoes and clothes if they have been exposed to the virus.
RHDV2 can also be transmitted through infected rabbits’ fur and meat, as well as contaminated feed and water. Manure and urine contain the virus, so bedding can serve as a source of infection if owners are not following adequate sanitation protocols for cleaning and disposal. The incubation period for RHD is 1-5 days from time of exposure to showing signs of infection.
The RHD virus can be very persistent and is aided by a wide range of viable temperatures and protection with the presence of organic material. Active viruses can survive for multiple days or months on surfaces (USDA APHIS 2020):
- 22-35 days at 72 degrees Fahrenheit
- 3-7 days at 99 degrees Fahrenheit
- can survive freeze-thaw cycles
- viable virus has been detected in a dry state (e.g., on a cloth or towel) for as long as 105 days
Rabbits that survive an RHD infection may remain a carrier and can shed the virus for 4-6 weeks (Hayhow, 2020).
Is there a cure?
Once a rabbit is infected, there is no cure for RHD, but vaccines are available in the U.S. and Ohio has been added to the approved list. This means that Ohio veterinarians can order and administer the U.S.-manufactured vaccine to rabbits. Vaccines can be cost prohibitive for some rabbit owners—take the time to identify veterinarians who are willing to administer the vaccine at a cost within your budget before approving this vaccination.
How do I protect my rabbits? Biosecurity Tips
Strict biosecurity practices in your rabbit facility are the best way to reduce the chance that RHD shows up in your facility. For effective results, owners should clean with soap and water to remove organic material (fur, manure, bedding etc.) before applying disinfectant. This is extremely important and challenging if there are any wood surfaces in your cages. Effective disinfection can be achieved with a 1:10 dilution of household bleach, allowing five minutes of contact time with the surface you are disinfecting. Quarantine new rabbits or those returning from shows for at least 30 days. (Quarantine includes housing rabbits away from the rest of the herd, ideally in a separate barn. Make sure you are feeding rabbits in quarantine AFTER you have fed the rest of the rabbits in your herd to control the spread of disease)
Sanitize any equipment that leaves your property (carriers going to a show, crocks loaned to a friend, etc.)
- Restrict access to anyone (other than family) to your rabbit facility
- Make sure you disinfect or change clothes and shoes before entering your rabbit facility, especially if you have visited a location off your property
- Restrict wild and feral rabbits, and predators from accessing your rabbit facility
- Wash hands between handling rabbits in different pens or cages
- If you are handling rabbits that are not yours, make sure you are thoroughly washing your hands and changing clothes.
- Clean and disinfect equipment, tools, footwear, feed and water containers, cages, etc.
- Control flies and biting insects
- Remove brush, grass, weeds, trash, and debris from rabbit facility
- Protect feed from contamination by flies, birds, rodents, etc.
- Do not feed grass or other forages that could be contaminated with the virus
- Do not use forages, branches, etc. for bedding
- Remove and bury or dispose of dead rabbits promptly
- Do not transport rabbits into or out of RHD quarantine areas
Owners should examine their biosecurity habits and determine if they need to step up their practices to aid in the prevention of RHD in their rabbit facility.
How do I report a suspected case of RHDV2?
If you notice wild or domestic rabbits that die suddenly and display bleeding from the nose, anus, or vent, send a report to your state veterinarian. The Ohio Department of Agriculture State Veterinarian reporting number is 614-728-6220. We encourage reporting from all residents if they notice wild rabbits around their property that appear to be dying for no apparent reason.
How do I stay updated on RHD information?
It is important to examine your biosecurity practices and adopt additional protocols to decrease the incidence of RHD in your rabbits. Educate others to be on the lookout for suddenly dying wild rabbits and provide them with the appropriate reporting channels for deaths they suspect might be linked to RHD.
Animal and Plant Health Inspection Service. (2020). General Guidance for Cleaning and Disinfection of Rabbit Hemorrhagic Disease Virus (RHDV) Contaminated Premises. [fact sheet]. United States Department of Agriculture. aphis.usda.gov/animal_health/downloads/rh dv-cleaning-guidance.pdf
Animal and Plant Health Inspection Service. (2020). Emerging Risk Notice: Rabbit Hemorrhagic Disease Virus, Serotype 2. [fact sheet]. United States Department of Agriculture. aphis.usda.gov/animal_health/downloads/rh dv1.pdf
Animal and Plant Health Inspection Service. (2019). Rabbit Hemorrhagic Disease. [fact sheet].United States Department of Agriculture. aphis.usda.gov/publications/animal_health/fs
California Department of Fish and Wildlife. (n.d.). Quick Facts About Rabbit Hemorrhagic Disease. [fact sheet]. nrm.dfg.ca.gov/FileHandler.ashx?DocumentID=17 9037&inline
California Department of Food and Agriculture. (May 2020). Keep Your Rabbits Safe from Rabbit Hemorrhagic Disease. [fact sheet]. cdfa.ca.gov/ahfss/Animal_Health/pdfs/CDFA ProtectYourRabbitsRHD.pdf
Hayhow, C. (2020, Jan/Feb). Rabbit Hemorrhagic Disease (RHD) in the U.S. Domestic Rabbits,48(1), 14-15.
Hreiz, J. (n.d.). ARBA Rabbit & Cavy Health Committee. [open letter]. American Rabbit Breeders Association. Retrieved from arba.net/wp- content/uploads/2020/05/rhdlettertoarba5.14.20.pdf