Rabbit haemorrhagic disease (RHD) is caused by the rabbit haemorrhagic disease virus (RHDV), a type of calicivirus which is fatal in non-immune rabbits. There are currently two pathogenic types of this virus in wild rabbit populations in Australia. Rabbit owners should talk to their veterinarian about making sure their rabbits are vaccinated with a vaccine that will protect against both RHDV1 and RHDV2 strains, where possible.
This disease occurs in wild and domestic rabbits in Australia causing acute internal haemorrhage and sudden death. There are two types of RHDV present in Australia (RHDV1 and RHDV2). RHDV1 is has been used as a biological control agent to reduce the feral rabbit population in Australia since 1996, while RHDV2 was first detected in 2015 in Australia, and has also significantly affected both wild and domestic rabbit populations.
What are the symptoms of RHDV?
RHDV damages internal organs such as the liver and intestines and may cause bleeding. Signs include fever, restlessness, lethargy, and poor appetite with bleeding from the nose and/or blood on the floor where rabbits are housed. Often infected rabbits will show no signs and die suddenly. If a pet rabbit is showing signs, a veterinarian should be contacted immediately. There is no cure for RHD but affected rabbits can be given supportive treatment.
How does RHDV spread?
All RHDV types can spread easily from infected rabbits in droppings, urine, secretions from the eyes and nose, and at mating. Spread can also occur from contaminated objects such as food, clothing, cages, equipment, insects (especially flies), birds and rodents. The virus can survive in the environment for three and a half months over hotter periods but up to seven and a half months in moderate temperatures.
How can I protect my pet rabbit against RHDV?
Rabbit owners should ensure their rabbits are vaccinated to protect them against RHDV.
Australian veterinarians have been using the CYLAP vaccine (which contains an inactivated RHDV1 strain) since 1997. When RHDV2 became the predominant strain in Australia, the recommendation for the use of CYLAP changed to an increased dose frequency of every 6 months, in the hope was that an increased vaccination regimen would be more likely to confer cross-protection to RHDV2, while acknowledging that CYLAP only contained RHDV1.
In May 2022, a new vaccine was approved (FILAVAC VHD K C+V) against both RHDV1 and RHDV2 virus strains. Rabbits should be vaccinated every 6-12 months against Rabbits Haemorrhagic Disease Virus (Calicivirus) to protect them against this fatal virus. Your veterinarian will be able to advise you on a suitable vaccination program for your bunny. For more information about vaccination against RHDV, see our article here.
No vaccination is 100% effective at preventing infection, and additional precautions should be taken to help to prevent infection (see below), As well as vaccination, to further protect your rabbits.
Reducing the risk of RHDV infection
RHDV can remain in the environment for an extended period and can be transmitted on objects and via some insects. The following precautions can reduce the risk of infection:
- Keep your pet rabbit indoors
- Rabbit-proof your backyard to prevent access by wild rabbits
- Regularly decontaminate equipment and materials including cages, hutches, bowls etc, with either 10% bleach or 10% sodium hydroxide
- Limit contact between and handling of unfamiliar pet rabbits
- Decontaminate hands, shoes and clothing after handling other than your own rabbits
- Control fleas
- Control insects (especially flies) as much as possible both indoors and outdoors
- Remove uneaten food on a daily basis.
