Rabbit Haemorrhagic Disease Virus (Calicivirus)

RHDV1 virus and RHDV1 (K5) variant

The RHDV1 strain of the rabbit haemorrhagic disease virus (Calicivirus) was first released in Australia in 1996 to control wild rabbits.

Over time the effectiveness of the virus has been decreasing. To boost the RHDV1 strain’s effectiveness, state and territory governments around Australia released K5, a new naturally occurring variant of RHDV1, in March 2017.

To protect pet and production rabbits from possible RHDV1 K5 infection, owners should ensure animals are protected through appropriate housing and vaccination. Studies funded by the NSW Department of Primary Industries and delivered by Invasive Animals CRC scientifically validated evidence that the currently available vaccine, Cylap®, is effective in protecting against RHDV1 K5.

Owners should also seek advice from their veterinarians on ways to implement additional biosecurity measures. These can include:

  • insect proofing
  • good hygiene practices, and
  • avoiding contact with other rabbits.

These measures may not only help to reduce the risk of RHDV1 K5 infection but also reduce the possibility of infection with other pathogens such as the myxoma virus or RHDV2.

RHDV2 virus

RHDV2 is a new strain of the Calicivirus that was first reported in Europe in 2010 and then in Australia in 2015. It is not known how the virus entered Australia. It was not released by any Australian government.

RHDV2 has been found to infect rabbits and hares, but has not been found to infect or kill any native or other introduced species.

Both the European brown hare and the European rabbit are invasive species to Australia and considered a threat to Australia’s environment and agricultural industry.

While there has been some interest among manufacturers to develop a vaccine to protect pet and production rabbits, currently there is no vaccine available in Australia for RHDV2. Before a vaccine can be used, it must obtain the necessary regulatory approvals.

The Cylap® vaccine currently used in Australia (for RHDV1) may only provide partial protection against the RHDV2 strain.

More information

Further information about the RHDV1 K5 virus release and recommendations for vaccinating rabbits against all strains of Calicivirus are available on the Australian Veterinary Association website.

Last reviewed: 12 August 2021
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