"Vaccination is our only protection"
Where did RCD come from?
Rabbit Calicivirus Disease (RCD) known in Europe as haemorrhagic viral disease (HVD) did not occur in Australia until recently. As haemorrhage is not a feature of this disease, the name RCD was adopted in Australia. RCD was first reported in China in 1984 and the disease had spread to Europe by 1986. By 1992 it had spread throughout most of western Europe. It was reported for the first time in the UK in 1992 and Australia in 1995. Australian authorities have approved the virus for use to control "wild" rabbit populations.
Where has RCD occurred in Australia?
The first reported case was in South Australia. Since then the virus has spread to parts of all states. It is anticipated it will continue to spread throughout most of Australia occupied by rabbits.
How is RCD spread?
The virus is present in the saliva and nasal secretions and contaminated excreta of infected rabbits. It is spread by either direct contact with infected rabbits, or indirectly in green feed, on clothing or other objects, or by carrion birds and other animals.
Studies have shown that this virus can survive in the environment for variable times at different temperatures. Insect vectors are also thought to be able to spread the RCD virus.
Can other species of animal catch RCD?
No. RCD only affects European rabbits (Oryctolagus cuniculus). Other species of rabbits and hares are not affected.
What are the clinical signs of RCD?
The time between the rabbit being infected and the first clinical signs of disease is very short, usually from 12 to 18 hours.
Clinical signs are seen as the rabbit becoming quiet and not eating or drinking, quickly leading to death. Death is caused by both cardiac and respiratory failure. Nearly 100% of rabbits that catch the disease die. They die quietly, with little signs of struggling or distress within about 30 hours of being infected.
There is no known therapy to reverse the disease.
Is the spread of RCD likely to continue?
Yes. Since November 1995 the virus has spread rapidly from South Australia to all other states. Mortalities of up to 100% in "wild" rabbit population have been reported. Unvaccinated pet and commercial rabbits will be at very high risk as the virus is released Australia-wide into the wild rabbit population. It is expected to persist in these areas for the foreseeable future.
How to protect your rabbit from RCD?
Vaccination against RCD can prevent pets, show rabbits and breeding rabbits from becoming infected with the disease and spreading it to others. Vaccination is the only way to protect domestic and commercial rabbits and prevent the disease spreading into these populations.
The majority of unvaccinated rabbits that become infected will die of the virus. To prevent exposure to the virus and other diseases such as myxomatosis, husbandry and management should include the following precautionary practices.
- Avoid direct and indirect contact with wild rabbits, including sources or supplies of green feed that could become contaminated.
- House rabbits in insect-proof facilities.
- Quarantine any newly introduced rabbits for at least 7 days away from other rabbits to ensure they show no signs of illness.
- Avoid contact with other people's rabbits, e.g. from possible contaminated hutches, equipment, feed and transport.
- Maintain hygiene and a disinfection programme using suitable disinfectants.
- Ask your veterinarian's advice immediately if your rabbit seems unwell.
- Protect your rabbit by vaccination. Your veterinarian will be able to advise you on this. Remember, annual booster vaccinations are essential to maintain protection.
Is a vaccine now available?
Yes. CYLAP® HVD vaccine was made available in Australia under permit by the National Registration Authority in November 1995. One dose will provide protection against RCD for twelve months in rabbits older than 10 weeks of age.
CYLAP® HVD vaccine is available from your veterinarian who will be pleased to advise you on the best means of protecting your rabbits.
The only practical and reliable way to protect your rabbit against RCD is by vaccination. The disease progresses very quickly and usually by the time you realise your rabbit is ill, death is imminent.
Your veterinarian will give you the best advice as to when to start vaccination. One dose is necessary at 10-12 weeks of age. An earlier vaccination can also be given in some circumstances if earlier protection is warranted.
Protection does not last forever. Immunity to this disease will wane over the course of a year leaving some rabbits susceptible.
An annual visit to your veterinarian will allow both a general health check and an annual booster vaccination against RCD. This will maintain immunity against RCD for a further year.
Your veterinarian will issue you with a vaccination certificate at the time of initial vaccination. It is important to keep this in a safe place as it may be required at rabbit shows, by breeders or as proof that your rabbit has been vaccinated.
The certificate should be presented to your veterinarian each year at the time of the annual booster vaccination so that it can be kept up to date.
Ask your veterinarian for further details about either the disease or the vaccine.
As with the use of any immunologicals or therapeutics, some side effects to vaccination can be expected in a few rabbits. These can include -
- depression and loss of appetite for a day or so after vaccination.
- site reactions seen as swellings that can sometimes lead to irritation with patches of hair loss about one week after injection.
- death due to anaphylactic reactions or complications with pre-existing disease conditions.
Fortunately these are rare.
Reports of loss of reproductive potential following vaccination have been made. These reports are associated principally with dwarf rabbits vaccinated during heat stress conditions. Dwarf rabbits have a semi dominant lethal gene that results in lower reproductive success rates and higher mortality of kittens up to weaning as compared to other rabbits. Heat stress conditions and high humidity have recognised adverse effects on male and female reproductive potential in all rabbit breeds. No adverse reproductive effects have been reported in standard breeds of rabbits held in controlled environmental conditions: As a general principle, vaccination is advocated when these stress conditions are absent.
- Only vaccinate healthy rabbits.
- Avoid vaccinating rabbits at times of environmental stress such as high ambient temperatures and high relative humidity. These environmental conditions may adversely affect the reproductive potential of rabbits, particularly in some breeds of rabbits such as dwarf rabbits.
If you have any questions at all, please don’t hesitate to phone one of our clinics.