Hawke's Bay release of fatal rabbit virus on cards

The calcivirus is a strain of the disease released illegally in New Zealand in 1998, to which many rabbits are now immune. Photo / File

A virus hoped to "knock down" up to 40 per cent of the rabbit population is expected to be released in Hawke's Bay in the coming months, as part of a nationwide programme.

This week it was announced the Ministry for Primary Industries agreed to the approvals required for the importation and release of the new rabbit virus disease strain, RHDV1 K5.

The virus causes a fatal haemorrhagic disease in the European rabbit, and is hoped to control the wild rabbit population. Rabbit-related damage is said to cost the agricultural industry millions annually in control and lost production.

The proposed re-release has been in the pipeline for over a year. Last year the Hawke's Bay Regional Council had agreed to release the virus once the approvals were received.

In light of this week's development, council land services manager Campbell Leckie said it would be revising its operational plans around the release of the virus.

It was planned to release it to 30 sites where historically rabbit numbers are high. He said he thought the release would be some time between April and June, and advised all domestic rabbit owners to vaccinate their pets.

It was not known how many wild rabbits could be impacted by the virus, however "knockdown" figures of between 30 and 40 per cent were expected.

This news was welcomed by Federated Farmers provincial Hawke's Bay president Will Foley, who said farmers spent a lot of money trying to control the population.

"Rabbits are very much a pest to farming operations. The degree of damage that the rabbit can cause varies from farm to farm, but for those farms where it is a pest ... they will welcome a new tool that can help them."

Federated Farmers was part of the New Zealand Rabbit Co-ordination Group, which also included representatives from councils, the Ministry of Primary Industries, and the Department of Conservation.

On their behalf, Environment Canterbury applied for the approvals needed to re-release the virus - which it was granted Tuesday.

Environment Canterbury Regional Leader Biosecurity Graham Sullivan said the decision was an important milestone for the national consortium of agencies seeking to release RHDV1 K5 to reduce the significant environmental and agricultural impacts of wild rabbits.

The New Zealand Veterinary Association has advised domestic rabbit owners to protect their pets by vaccinating them from 10 to 12 weeks of age, with boosters given to ensure ongoing protection.

"The new strain set to be released in autumn 2018 is just as deadly to pet rabbits as the existing strain. However, there may be an increase in cases among the wild rabbit population therefore increasing the possibility of exposure of the virus to pet rabbits."

A number of biosecurity measures were also recommended, including removing uneaten food, keeping pets inside, rabbit-proofing backyards to prevent wild rabbits access, and control of insects (with flies being the main source through which the virus is spread).

In 1998 a strain of the rabbit calcivirus was illegally released into New Zealand. With many rabbits now immune to it, it is hoped the re-release of a different strain would overcome the protective effects of this immunity.

In Hawke's Bay, blood sample monitoring has shown average immunity has gone from 8 per cent to 70 per cent in the past decade.