Calicivirus has not been released in 2021 because environmental conditions are not suitable.
Rabbit management requires an integrated, collaborative and strategic plan of action using a range of tools and techniques.
The most effective outcomes occur when management efforts look beyond property boundaries and involve a high degree of cooperation between affected landowners, community groups and other stakeholders. Landowners have primary responsibility for managing rabbits on their land.
Calicivirus is used as one option in a suite of available management options to avoid very high rabbit population numbers.
Biosecurity Tasmania (BT) provides advice on rabbit control and regulates the annual release of calicivirus. This is because calicivirus is a biological control agent, and its effective use can be more complex than other control options.
BT officers assess properties in response to enquiries from landowners and determine the suitability for release of calicivirus or whether other control options may be more appropriate.
What is happening in 2021?
As a consequence of the good growing conditions, calicivirus has not been released this year. It is unlikely that any releases will take place in 2021.
With this year’s high rainfall, there has been and still is an abundance of food available, especially grass, so conditions continue to be good for rabbits to breed. The ongoing abundance of food means that rabbits are less likely to take calicivirus treated bait.
We do not release calicivirus when there are rabbits under the age of 2 months. This is because young rabbits have a natural immunity to calicivirus, and if exposed to calicivirus at this age they retain this immunity for the remainder of their lives. Releasing calicivirus where there are young rabbits puts Tasmania at risk of a population of immune rabbits.
BT will continue to monitor populations across the state, however calicivirus release has not occurred this year.
The release sites from last year (2020) are still available on the DPIPWE website.
What strain of calicivirus is used in Tasmania for rabbit control?
RHDV1-K5 is the only strain released by Biosecurity Tasmania. RHDV1-K5 is a strain of the original RHDV1 virus, which was first released in Tasmania in 1997.
In 2016, a new variant of calicivirus, RHDV2, was detected in Tasmania. Previously detected on the mainland, it is not known how RHDV2 arrived in Australia or Tasmania.
RHDV2 is not registered for use as a biological control agent and is NOT released by the Tasmanian Government.
How best to protect domestic rabbits?
It is important to remember that despite not being released this year, calicivirus is present in the Tasmanian environment.
Rabbit owners are encouraged to talk with their veterinarian regarding protection against caliciviruses. There is currently no approved vaccine available in Australia against RHDV2.
Strategies for protecting pet and farmed rabbits from caliciviruses, including important biosecurity measures, can be found on the DPIPWE website.
Where to go for more information?
Rabbit owners and landholders are encouraged to visit the Department website for more information on calicivirus and rabbit management.