The organisation says the RHDV virus causes a haemorrhagic disease with a high mortality rate. Susceptible wild and pet rabbits can be infected if exposed to the virus, which is spread by insect vectors, such as flies, and by direct contact between an infected rabbit (dead or alive) and a susceptible rabbit.
The SPCA claims that in welfare assessments, the level of suffering of rabbits affected by RHDV is reported to be "moderate to severe," and the time taken for the rabbit to lose consciousness and die can be prolonged.
A media release stated rabbits may have fever, loss of appetite, lethargy, fatigue, convulsions, signs of suffocation, opisthotonus (a condition in which the body is held in an abnormal posture with the body rigid, the head thrown backward, and a severely arched back), sudden crying, haemorrhaging, and uncoordinated movements or paddling of the limbs. However, infected rabbits may show no external signs of disease but suddenly die from organ failure within 12 to 36 hours of the onset of infection.
"A large number of pets could be at risk so we are urging all rabbit owners to contact their veterinarian immediately for up-to-date advice on how to protect their rabbit from the new strain of this deadly virus," said Dr Dale.
Dr Janine Duckworth, leader of Landcare Research's rabbit biocontrol initiative, said last year the virus could help farmers slash the number of rabbits by up to 30 per cent and that rabbit damage costs the agricultural industry tens of millions of dollars in control and lost production each year.
Duckworth said K5 had undergone thorough testing in Australia prior to release here, and that the K5 strain would be a boost to rabbit control by killing some of the rabbits now immune to rabbit haemorrhagic disease (RHD), which was first illegally imported in 1997.
She said the new strain would provide farmers with a more cost-effective and efficient solution. This should make follow-up with conventional trapping, shooting and dogs more effective and worthwhile too, Dr Duckworth said. However, K5 wouldn't be a "silver bullet" to New Zealand's rabbit problem.
A vaccine is available for owners of domestic rabbits to protect their pets, but immunity is usually not acquired until 21 days after vaccination.
Tips for rabbit owners
* Contact your veterinarian for up-to-date advice about the best way to protect your rabbit from the virus. You should have your rabbits vaccinated or make sure they are up to date with their vaccinations. This should be done urgently because the virus may be released as early as late March, leaving little time to get rabbits vaccinated and develop immunity.
* Prevent indirect and direct contact between domestic and wild rabbits.
* Avoid cutting grass and feeding it to rabbits if there is the risk of contamination from wild rabbits. Also be careful of fresh vegetables as some may be grown in areas contaminated with RHDV.
* If you are in contact with rabbits other than your own, wash your hands with warm soapy water between handling rabbits.
* Good insect control is also important and will help reduce the risk of exposure to the virus. Insect control could include insect-proofing your rabbit's enclosure or keeping your rabbit indoors.
* Clean anything that rabbits come into contact with by using 10 per cent bleach, 10 per cent sodium hydroxide, or Virkon (available from your local vet).
