The Australian Government has planned to release the Calicivirus (RHDV) strain K5 in March 2017 in more than 600 sites within Australia to control wild rabbit populations. The K5 strain is a mutation of the existing RHDV1 and is already widespread in Australia.

In a nutshell:

There are now four types of Calicivirus with significance for pet rabbits in Australia:

  • RHDV1 (the original virus released in 1995)
  • RHDV1A (not in Victoria)
  • RHDV1 – K5 variant (release planned in March 2017)
  • RHDV2 (detected in Melbourne 2016)

We have only 1 vaccine, Cylap which is registered for vaccination against RHDV1. Based on scientific evidence to date the existing vaccine Cylap is also effective against the K5 strain. However, the Cylap vaccine is not fully protective against RHDV2 and it is not known how long the immunity lasts. There is evidence of some cross protection between type 1 and type 2 viruses so keeping your rabbit up to date with vaccination is essential.

We recommend that all owners of pet rabbits ensure that their rabbits are vaccinated/ up to date with their vaccinations as Calicivirus causes a fatal disease in rabbits known as Viral or Rabbit Haemorragic disease (VHD or RHD). All Calicivirus strains are considered contagious to rabbits and hares and can be transmitted via direct contact with infected rabbits, urine, faeces, saliva, insects (including flies), contaminated bedding, clothing, footwear, and equipment.

Change in Vaccination Protocol

Our clinic has adopted the vaccination protocol recommended by the Australian Veterinary Association (AVA) against Calicivirus as follows:

  • Young Rabbits– Vaccinate from 4 weeks of age, repeat doses at 8 and 12 weeks, and then vaccinate every 6 months.
  • Adult rabbits– Vaccinate every 6 months.
  • Unvaccinated adults, or overdue adults – Vaccinate twice 1 month apart, then every 6 months.

This protocol is off-label as Cylap is not registered for 6 monthly use or for use against RHDV2.

It is not known to what extent this will confer protection, but based on studies conducted so far, vaccinating every 6 months does not have negative health effects. Our vets will do a health check on your pet rabbit to determine that your pet is in good health for a vaccination and weigh up the benefits of a 6 monthly vaccination protocol and the risk of vaccination reactions for your pet rabbit.

What else can owners do to reduce the risks?

We recommend that rabbit owners take the following extra precautions:

  • Prevent direct and indirect contact between domestic and wild rabbits.
  • Avoid cutting grass and feeding it to rabbits if there is the risk of contamination from wild rabbits.
  • Good insect control is also important and will help reduce the risks of introduction of both RHDV and Myxomatosis. Insect control could include:
    • Insect proofing the hutch for rabbits kept outside
    • Where possible keep your rabbits indoors.
    • Keep indoor/outdoor rabbits inside at high risk times of the day: dawn and dusk
  • Wash hands, with warm soapy water between handling different groups of rabbits.
  • Quarantine (keep separate) new rabbits for at least 1 week before introducing them to your current rabbits.
  • Take unwell rabbits to your rabbit-knowledgable vet. If you suspect that your rabbit has been infected with calicivirus, isolate from other rabbits and call the vet clinic as soon as possible.
  • All cages and equipment should be thoroughly cleaned and disinfected with 10 % bleach or 10 % sodium hydroxide. Please read the disinfectants material safety data sheets prior to use. Calicivirus lives in the environment for a long time (up to 3 or 4 months)

For more information please refer to the link http://www.ava.com.au/rabbit-calicivirus or call us on 9850 5046

Dr Alice Phan BVSc (vet and rabbit owner)