A DEADLY new strain of calicivirus is set to be released across a host of sites in the east in the first week of March to cull the wild rabbit population.

The WA Department of Agriculture and Food is supporting preparations to release the Rabbit Haemorrhagic Disease Virus, known as RHDV1 K5, at more than 100 community-led release sites, including in the shires of Mundaring and Toodyay as well as the City of Swan.

Department research officer Susan Campbell said RHDV1 K5 would be a vital tool to reduce the population of pest rabbits, which cost more than $200 million in lost agricultural production each year and wreak havoc on the environment and biodiversity.

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“However, RHDV1 K5 is not expected to result in a 90 per cent reduction of pest rabbit populations, as seen with other biocontrol releases,” she said. “Rather, it is expected to boost current management and help slow down the increase in rabbit numbers.”

Dr Campbell warned owners of domestic rabbits to ensure they were aware of the virus and know how to protect their pet rabbits from infection.

“As the virus is contagious and can be spread by direct contact or by mosquito vector, we urge owners to contact their local vet for advice on vaccination which also covers the existing strain of the virus, and to take additional precautions such as keeping rabbits in insect-proof enclosures or inside.”

RSPCA WA animal services manager Jess Moore said RHDV1 K5 was fatal to rabbits without immunity.

Dr Moore said while the currently available RHDV1 vaccine Cylap had shown some protection against the K5 strain in small pilot trials, the RSPCA believed further trials must be undertaken to provide real certainty regarding its effectiveness.

“For now, the Cylap vaccine is the best chance rabbit owners have of protecting their pet from the release of this new strain,” she said.

“While we would prefer to see the release of RHDV1 K5 delayed until the full efficacy of Cylap against the K5 strain can be determined, we are urging rabbit owners to go ahead with the vaccination to give their pet the best chance of protection against this deadly virus.”