Rabbit Hemorrhagic Disease (RHD) is now present in the State of Wisconsin, is highly contageous and can pose a danger to both wild and domestic rabbits.
RHD had been seen primarily in the southwestern United States beginning 2020 but it has been spreading rapidly across the country. RHD is often a very swift and sudden killer, giving little warning. Rabbits may die without showing any symptoms at all.
RHD has now been found in Wisconsin in the LaCrosse area after there being confirmed cases in Minnesota earlier in 2022. Please read more below on symptoms that you can see, how it's transmitted and other resources of information.
Fortunately, there is a vaccine that can be given to rabbits that is effective in preventing the RHD virus. This vaccine is approved for use in Wisconsin and we have been providing vaccinations for our rabbit patients since October of 2021.
Your rabbit will need to receive the initial vaccine and would need a second dose 21-28 days later. This vaccine would then be given yearly throughout your rabbit’s life to protect against RHD.
We are also recommending that rabbits that receive the vaccine be microchipped to document that your individual rabbit received the vaccine. If your rabbit is social and has, "play dates", some organizations that sponsor these events may require that your rabbit be microchipped in the future. If you would like us to place a microchip during your appointment, the cost is $40. Please call us at 608-294-9494 if you have any questions or to schedule an appointment.
Healthy Pet is now requiring that all rabbits boarding in our clinic be vaccinated against RHD.
Please call us at 608-294-9494 to make an appointment if you would like to schedule this vaccine for your rabbit.
What is Rabbit Hemorrhagic Disease?
Rabbit Hemorrhagic Disease Virus (RHDV) is a highly contagious disease caused by a calicivirus that affects rabbits. This includes wild and domesticated European rabbits (Oryctolagus cuniculus), from which our own domesticated rabbits are descended. Until 2020, RHDV had not been known to affect North American native rabbits or hares, such as cottontails, snowshoe hares, and jackrabbits however RHDV is now causing death in those species.
RHDV2 is the most recent strain of RHDV that emerged in 2010 in Europe and quickly spread in the Mediterranean. RHDV2 has replaced the original strain in many countries. In 2015, RHDV2 was first detected in Australia and it quickly spread coast-to-coast in the rabbit population there in just 18 months and became the dominant strain replacing RHDV1.
RHDV2 is very resistant to extreme temperatures. it can be spread through direct contact or exposure to an infected rabbit's excretions or blood. The virus can also survive and spread from carcasses, food, water and any contaminated materials by either direct contact or via blood feeding insects. People can spread the virus indirectly by carrying it on their clothes.
RHDV2 is often a very swift and sudden killer, giving little warning. Rabbits may die without showing any symptoms at all. Any sudden and unexplained rabbit death in Wisconsin is suspicious and should be reported to your veterinarian as a possible to investigate if the death was caused by RHDV2.
Symptoms may include:
- Sudden Loss of appetite
- Unexplained Lethargy
- High fever
- Bleeding from nose, mouth, or rectum
- Difficulty breathing
- Sudden death
Incubation Period of RHDV2 is 3-5 days until onset of symptoms, then death within 3-5 days.
Death Rate (Mortality)
- In the 2020 Southwest US and Mexico RHDV2 outbreak, officials have reported death rates to be around 90% in confirmed cases of RHDV2.
- Survivors: Rabbits who survive RHDV2 are carriers and shed the virus for at least 42 days, perhaps longer.
- Asymptomatic Carriers: Some rabbits may have little to no symptoms of RHDV2 (subclinical/asymptomatic) but may shed virus for up to 2 months.
- Transmission Routes: Rabbits are infected by oral, nasal/respiratory, or ocular exposure to the virus, or by blood-feeding insects.
- Cause of Death: RHDV causes necrotizing hepatitis, and may cause necrosis of the spleen. There may be internal or externally visible bleeding. Death occurs from liver failure or hemorrhage due to an impairment in the blood’s ability to clot.
- Durability of Virus: The RHDV Calicivirus is a very hardy virus, remaining viable in the environment outside a host for a significant length of time.
- Survives 105 days at 68F on fabric – meaning it remains stable for 3.5 months at room temperature
- Survives 225 days at 39F (just above freezing temperatures)
- Survives freeze/thaw cycles
- Survives heat of 122F for one hour
- Seasonal Outbreaks: Where the virus has a reservoir in wild rabbits or feral/stray domestic rabbits, seasonal outbreaks are expected year to year. Flies are apparently a significant vector or cause of disease transmission so seasons where flies are more common may be linked to RHDV activity.
- There is no known cure for RHDV
- RHDV treatment is supportive care in isolation
- There are currently no known effective anti-viral drugs or other treatments available
For more information, see the following RHVD webpage at the Wisconsin Department of Agriculture
And this Fact Sheet from the USDA (the fact sheet says there is not a vaccine available but that has changed since it was published and we now have a durable vaccine to protect against RHDV2.)
Additional information can be found at the House Rabbit Society Website