New strain of biological control agent for rabbits
3 February 2016
A new strain of the rabbit calicivirus called Rabbit Haemorrhagic Disease Virus, K5 (referred to as RHDV K5 or simply 'K5'), is likely to be released in spring 2016 or autumn 2017 to assist land owners in their efforts to control rabbits.
The Department of Economic Development, Jobs, Transport and Resources (DEDJTR) is partnering with the Invasive Animals Cooperative Research Centre in the development, monitoring and release of RHDV K5.
This new strain is predicted to yield better results in cooler-wetter regions, such as Victoria, where the current RHDV strain hasn't been so successful.
DEDJTR's rabbit specialist John Matthews said K5 is not a new virus.
"K5 is a strain of the existing virus already established and widespread in Australia and has exciting potential for Victoria.
"For some, K5 will be seen as a once in a generation opportunity to improve biological control options for rabbits in Australia," he said.
Mr Matthews said K5 was selected because it may overcome the protective effects of a benign calicivirus which naturally occurs in Australia's rabbit population. It is species-specific to European rabbits and existing vaccines can protect pet and farmed rabbits against the K5 strain.
"K5 has the potential to kill more rabbits and will provide for a faster death than the current strain of RHDV.
"DEDJTR has commenced biological sampling at 13 long-term rabbit population monitoring sites across Victoria in the lead up to the release of K5, in order to be able to accurately monitor the spread and impact of K5 once released, "he said.
Mr Matthews said an additional four sites will be monitored more intensely to establish the vulnerability of rabbit populations prior to release and to assess the impacts of K5 on rabbit populations.
"A key message for landowners is that K5 isn't a silver bullet and is not expected to result in population reductions like those seen in 1996-97 when calicivirus first arrived in Victoria.
"Knockdowns are expected to be improved by anywhere from zero to 40 per cent, depending on location and susceptibility of the rabbit population to K5, however some vulnerable rabbit populations may be affected at higher rates," he said.
"The combination of an improved biological control agent in K5, community-led rabbit management and using best practice rabbit management principles, should provide an opportunity to manage and maintain rabbit numbers at low levels."
Mr Matthews said in late 2015, a new variant of RHDV (RHDV2) that was not previously known to occur in Australia was identified in some captive and wild rabbits in Victoria. This virus is not the RHDV K5 that is proposed for release.
RHDV2 has the ability to also infect some species of hares, but so far has not been reported to infect the only hare species present in Australia, the European brown hare.
Further information regarding the vaccination of pet or farmed rabbits against the existing RHDV, RHDV K5 or RHDV2 can be found on the Office of the Australian Chief Veterinary Officer website.
Land owners and community groups are encouraged to become involved in the future K5 release.
Categorised under: Agriculture,Biosecurity