Rabbit Calicivirus causes RCD (Rabbit Calicivirus Disease), and is 100% fatal in pet rabbits.
It is also known as RHD (Rabbit Haemorrhagic Disease) and much less frequently as VHD (Viral Haemorrhagic Disease).
RCD was being researched in South Australia by the CSIRO on Wardang
Island but 'escaped' in October 1995 and the CSIRO estimated tens of
thousands of rabbits died within several weeks - However some
(sensationalist?) reports estimated that up to 10 million rabbits died
within 8 weeks... needless to say this number probably died within 1-2
years because once it was noted that no native species were being
affected by RCD, there were controlled RCD releases through out all of
Australia a year after the initial 'escape'.
Although cats get a respiratory disease caused by a cat calicivirus (and are routinely vaccinated against this), it is a completely different virus and is not transmissable between cats and rabbits. There was a significant impact indirectly on wild life as feral cats preyed heavily on young rabbits and without this source of food were believed to have attacked and eaten even more native species.
Many believe that the release of the RCD virus was deliberate:
smuggled ashore by farmers from Wardang Island off of Yorke Peninsula.
Farmers were frustrated by the apparant lack of action by the scientists
BUT extreme care MUST ALWAYS been taken when introducing biological
controls as there have been disasters in the past when thorough research
had not been adequately undertaken. The introduction of the CANE TOAD
is a classic example.
In most places of Australia, the death rate was over 90%, with the desert and semi-arid region rabbits having the highest mortality rates (up to 100%). The death rate is much lower (30 - 40%) in the wetter areas for some unknown reason. Very young rabbits don't die from the disease either due to their immature blood clotting sytems not being damaged by the virus, or due to any maternal antibodies passed on to them by their mothers. These young rabbits grow and can produce resistant young.
Currently the wild rabbit population in Australia is approximately 50% of the pre-RCD release population.
Most wild rabbits that die from RCD are not found as they usually die
in their burrows and warrens. Usually rabbits are still in good body
weight condition and die suddenly. In pet rabbits you may note lethargy
and loss of appetite, body spasms, sometimes sudden onsset breathing
difficulty, arching of the back, followed soon by bleeding from the
nose, mouth and/or eyes and, unfortunately, death.
The virus is believed to spread in a few ways: flies, biting insects
(fleas and mosquitos), contaminated food, direct contact between
rabbits, or contact with urine, faeces or secretions (eyes and mouth)
from an infected rabbit. The greater spread of the disease in desert
regions is thought to be due to the very large number of flies, especially blowflies,
that feed on the dead rabbits and then spread the virus to vegetation
other rabbits eat, or to the coat of a rabbit that then contracts the
virus by grooming its coat.
Wild rabbits also affected by myxomatosis infection have a much higher, likely 100%, death rate.
Prevention of RCD in pet rabbits
To minimise the risk to your pet rabbits we advise:
- Ensure you vaccinate your rabbits against RCD. Kits can be
vaccinated from 6 weeks of age but if teh first vaccination is before 10
weeks of age, then a booster vaccination is required 2 -4 weeks after
the initial vaccination. Then vaccinate ANNUALLY.
- Ensure your rabbit's hutch is mosquito proof.
- Apply monthly flea control eg Revolution
- Avoid handling other people's rabbits and ensure strict hygiene if
you do - REMEMBER that any secretions or faeces that is on your clothing
is a potential source of RCD.
- Ensure there is no possibility of contact with wild rabbits.
- Purchase packaged Timothy Hay and not hay or straw from local farms.
If you have any questions, please call and ask, we'll be pleased to help!