What is Rabbit Calicivirus in Australia and how do I protect my rabbit from it.
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 strains of this virus in wild rabbit populations in Australia, with a third now released called RHDV1a. Rabbit owners should ensure their rabbits are vaccinated to protect against the original strain of the virus, RHDV1. However, the vaccine does not protect against all strains, so additional measures must be taken to reduce the risk of rabbits being exposed to RHDV.
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 remedy for RHD but affected rabbits can be given supportive treatment.
How does RHDV spread?
All RHDV strains 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 with Cylap® vaccine to protect against RHDV. Veterinarians should follow current Australian Veterinary Association guidelines to maximise vaccine protection. However, as Cylap® does not fully protect against all strains of RHDV, additional measures must be taken to reduce the risk of infection.
RHDV1 - an effective vaccine, Cylap® has been available for many years to protect rabbits against this strain of the virus. Rabbits must be vaccinated annually to maintain protection against RHDV1.
RHDVK5 - the current evidence indicates that vaccination with Cylap® will provide protection against RHDVK5, but further research is needed. It is still essential that all rabbits are vaccinated and that precautions are taken to help to prevent infection (see below).
RHDV2 - no vaccine is available in Australia that specifically protects against RHDV2. However, a modified vaccination protocol may provide some protection and thus it is still essential that all rabbits are vaccinated and precautions are taken to help to prevent infection (see below).
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 insects (especially flies) as much as possible both indoors and outdoors
Remove uneaten food on a daily basis.