Rabbit Hemorrhagic Disease (RHD) is a highly fatal disease in domestic rabbits and some types of the virus are deadly for wild rabbits. RHD is considered a Foreign Animal Disease (FAD) in the United States (U.S.). The disease poses no threat to humans. The disease is caused by a calicivirus, which has 3 different pathogenic groups. One of the serotypes is Rabbit Hemorrhagic Disease Virus, Serotype 2 (RHDV2). This serotype was discovered in France in 2010. In 2018, RHDV2 was diagnosed in a pet rabbit in the state of Washington. In the spring of 2020, the disease was found in wild and domestic rabbits in the states of Arizona, California, Colorado, Nevada, New Mexico and Texas. Oklahoma rabbit owners need to be aware of this emerging threat.
The virus is highly contagious. It spreads through direct contact between infected rabbits. A dead carcass of a positive rabbit contains large amounts of the virus, and the virus survives for long periods of time in the decaying tissues. Other means of spread are through meat, fur, contaminated food and water or other materials that come in contact with the virus. Biting insects can transfer the virus from animal to animal. Humans can spread the virus on shoes or clothing. The virus is thought to be found in all rabbit secretions such as urine, feces, blood, and respiratory secretions of infected rabbits.
The first clinical signs that most people observe with RHD are dead rabbits with dried blood in the nasal passages. Other signs seen are anorexia, dullness, vocalization, respiratory signs (increased respiration rate, frothy and bloody nasal discharge), neurological signs (ataxia, paddling, convulsion, paralysis), and cyanosis of the mucous membranes. If the disease continues to progress, the animal will show signs of jaundice, lethargy, and weight loss. These animals will usually die of liver failure, but some will survive. Diagnosis is based on clinical signs and laboratory testing.
There is no specific treatment for RHD. Sick rabbits should be isolated from all other rabbits and owners should consult with their veterinarian. Veterinarians will provide supportive care, but the best option of controlling the disease is to focus on preventing the disease.
Other countries have a RHDV2 vaccine, but the vaccine is not approved for use in the U.S. If the disease is found in Oklahoma, Oklahoma State Veterinarian Dr. Rod Hall will petition the Food and Drug Administration for permission to import the vaccine. Rabbit owners should contact their veterinarian for more information about the vaccine.
Until a vaccine is available, the only means of preventing RHDV2 is biosecurity. The USDA recommends the following biosecurity protocols:
- Do not allow pet, feral, or wild rabbits to have contact with your rabbits or gain entry to the facility or home.
- Do not allow visitors in rabbitries or let them handle pet rabbits without protective clothing (including coveralls, shoe covers, hair covering, and gloves).
- Always wash hands with warm soapy water before entering your rabbit area, after removing protective clothing and before leaving the rabbit area.
- Do not introduce new rabbits from unknown or untrusted sources. Do not add rabbits to your rabbitry from animal shelters or other types of rescue operations.
- If you bring outside rabbits into your facility or home, keep them separated from your existing rabbits. Use separate equipment for newly acquired or sick rabbits to avoid spreading disease.
- Sanitize all equipment and cages moved on or off premises before they are returned to the rabbitry. We recommend disinfecting with 10% bleach or 10% sodium hydroxide mixed with water.
- Establish a working relationship with a veterinarian to review biosecurity practices for identification and closure of possible gaps.
Rabbit owners should review their biosecurity plan. If they do not have a biosecurity protocol, they should consult with their veterinarian and develop one.
Additional steps recommended by the USDA to prevent the disease are
- If you live near or visit an area where this disease was confirmed, do not touch any dead wild rabbits you may see. You may contact your local veterinarian, state and federal animal health officials to learn if RHDV2 has been detected in your area.
- If you see multiple dead wild rabbits, report it to state wildlife officials.
- If you own domestic rabbits, do not release them into the wild. If your rabbits appear ill or die suddenly, contact your veterinarian.
- If you volunteer at animal shelters or wildlife rescue facilities, be aware that this disease has been found in feral rabbits. If rabbits appear ill or die suddenly, contact the facility’s veterinarian.
- Anyone working with rabbits should always practice good biosecurity. This includes basic steps like washing your hands before and after working with rabbits and not sharing equipment with other owners.
RHD is a reportable disease. If an individual finds several dead rabbits in the wild or a rabbit owner suspects the disease in their rabbits, they should contact their local veterinarian or Dr. Rod Hall at the Oklahoma Department of Agriculture, Food, and Forestry at 405-522-6141.
Rabbit owners with questions about RHDV2 should consult with their local veterinarian or their local County Oklahoma State University Agriculture Extension Educator. For additional information, a fact sheet from the USDA can be found at https://www.aphis.usda.gov/publications/animal_health/fs-rhdv2.pdf.
Read more in the July 2020 issue of Oklahoma Farm & Ranch.