Rabbit biocontrol: RHDV1 K5 national release

Page last updated: Wednesday, 22 February 2023 - 4:34pm

Please note: This content may be out of date and is currently under review.

The national release of a Korean strain of Rabbit Haemorrhagic Disease Virus, known as RHDV1 K5 took place during the first week of March 2017.

This is the first time in 20 years that a new rabbit biocontrol agent has been released into Australia. More than 600 release sites were selected nationally. The virus was released at 110 sites in Western Australia.

The release of this new rabbit virus strain is part of a 20 year national biocontrol plan for rabbits.

Map of 2017 release sites
Locations where RHDV1 K5 was released in 2017

Preliminary analysis

Preliminary analysis has shown an observed reduction of up to 36% in rabbit numbers at Australian release sites following the release of RHDV1 K5 in March 2017.

Initial data is positive, however, long term success will be measured and seen through environmental benefits and increased productivity for the agricultural sector. It is important to stress that not all sites where RHDV1 K5 was released did experience the same results and results are based on all data collected.

The outcomes of the national RHDV1 K5 release will be published in a scientific report in the first half of 2019. 

Domestic pet rabbits and breeding stock

  • Owners should seek advice from their veterinarian regarding vaccination.
  • Owners should implement biosecurity  measures to protect their animals from infection.
  • Download this flyer for distribution.


RHDV1 K5 is not a new virus. RHDV1 K5 is a naturally occurring Korean variant of the Rabbit Haemorrhagic Disease Virus (RHDV). Its release is expected to ‘boost’ current management and help slow down the increase in rabbit numbers.

RHDV1 K5 is highly contagious, can be spread by insect vectors, and other animals feeding on infected carcasses may excrete the virus.

Domestic rabbit owners are advised to seek advice from their local veterinarian and use protective biosecurity measures to help keep their rabbits safe from infection. 

You can help

Landholders are asked to help maximise outcomes from the virus release by undertaking follow-up conventional control, coordinating any future releases at a landscape level, report rabbit sightings, and submit samples from dead rabbits for testing.

RHDV1 K5 is now available as a commercial product to authorised users, however landholders are asked to wait for late Spring or Autumn before releasing the virus.

Training and virus distribution

Winter is not best practice period for release. Late Spring and Autumn are ideal conditions for deliberate releases of RHDV1 K5, when insect activity is high, but when there are also a low proportion of very young rabbits present. 

The supply and use of RHDV1 K5 in WA to authorised users was enabled under the Biosecurity and Agriculture Management Regulations Amendment 2017 (Government Gazette Friday, 3 February 2017). Under the regulations, anyone who will be handling and mixing the liquid suspension virus must complete on-line training to become authorised users of RHDV. RHDV1-K5 Authorisation Training is available from DPIRD's Client Online Training website.

Coordinated, landscape scale release of rabbit biological control viruses will maximise effectiveness and produce greater results than patchy, individual landholder releases. DPIRD recommends land managers contact their local biosecurity group before applying for the virus to coordinate a release or to determine if a release has already occurred within their area. Biosecurity group contact details are available within the online RHDV1 K5 training package. 

The commercially available rabbit biological control virus, RHDV1-K5, can be released by authorised users in Western Australia who have completed their training. Although DPIRD keeps a record of authorised individuals and their post code, we are not informed of when or where individual releases of the virus occur. DPIRD does not routinely undertake virus release for pest rabbit control.  Under collaborative research programs, DPIRD has undertaken a few releases since the initial 2017 nation-wide release of RHDV1-K5, at trial sites.

One vial of RHDV1-K5 will treat approximately 150 hectares of rabbit prone land (less if rabbit density is high). The virus is either mixed onto bait (oats or carrots), or can be directly injected into live rabbits. Both techniques require some pre-feeding to get rabbits eating bait or for attracting them into approved wire cages. Oats should be standard intact oats with husks attached and carrots should be good quality and freshly diced. One vial reconstituted product (10 mL) diluted with an additional 90 mL of water (100 mL total volume) is sufficient to treat 10kg of freshly diced carrots OR 5kg of oats. For information on the delivery of RHDV, see the PestSmart webpage.  For more information about the cost of the virus, contact the NSW Department of Primary Industries (DPI) Virology labs (02) 4640 6337 or virology.enquiries@dpi.nsw.gov.au.

Submit reports and dead rabbit samples

The Invasive Animals Cooperative Research Centre (CRC) expects RHDV activity to increase in the coming months and the RHD Boost research team encourages landholders to report any rabbit sightings or signs of disease, and submit samples from dead rabbits.

A national approach is in place for the collection and testing of all potential RHDV+ rabbit samples. This process allows for national coordination of data, samples, messages and provides all labs access to the samples they need. This will continue for at least the next two years, and hopefully longer.

Online information can be provided (once you have a sample or samples) via the FeralScan website or the FeralScan smartphone app – available via iTunes and GooglePlay.

For any questions or technical support regarding these processes please contact Emma Sawyers on 02 6391 3834 or rhdboost@invasiveanimals.com.

Carry out integrated control

The release of RHDV1 K5 is part of a 20 year national biocontrol plan for rabbits. It will not result in a 90% reduction of pest rabbit populations, as seen with other biocontrol releases.

It is critical then that landholders undertake an integrated and complementary pest management approach, with conventional control measures put in place following release of the virus. This could include starting a conversation with neighbours with the aim of integrated best practice rabbit control at a landscape scale.

Land managers must also consider concurrent control for predators such as foxes (potentially looking for alternative food sources in the absence of rabbits). A reminder to carry out Integrated Pest Management is included on the virus product label directions and in the online RHDV1 K5 training package.

video series on best practice rabbit control has been released by the Invasive Animals CRC to increase skills in control programs. The videos include instructional ‘how-to’ videos to demonstrate control procedures such as poison baiting, baiting with biocontrol agents, rabbit warren fumigation, rabbit warren ripping and harbour destruction. It also includes video instructions for the RabbitScan (FeralScan) app and information on the RHDV1 K5 release.

Why do we need a new biocontrol agent?

Rabbits are Australia’s most destructive agricultural pest animal, costing upwards of $200 million in lost agricultural production annually. Two rabbits can become 200 rabbits in just two years, and in another two years that could be 40,000. It is vital to keep on top of the problem with new interventions and new tools.

A Czech strain of Rabbit Haemorrhagic Disease Virus (RHDV) was first released in Australia in 1996 and proved extremely effective, knocking down up to 90% of the pest rabbit population in some parts of Australia.

However, in 2009 a native benign calicivirus, called RCV-A1, was identified as a factor for RHDV being less effective in cooler and wetter climates.

The release of RHDV1 K5 comes after more than 5 years of testing through the Invasive Animals Cooperative Research Centre (IACRC) RHD Boost project, with major financial and in kind resources provided by the Australian government, state governments, and industry and non-government organisations. 

After testing 38 variants of RHDV, this project noted that RHDV1 K5 should work better in the cool-wet regions of Australia where the current variant has not been so successful.

Animal welfare considerations

  • Given the short disease time (between 24 and 72 hours after infection) and the sudden death from rapid organ failure, RHDV1 K5 is one of the most humane control methods for rabbits (even more so than the Czech strain).

  • RHDV1 will only infect the European rabbit and will not harm humans, other pets or native species.

  • Approval to use RHDV1 K5 included a stringent approval process by the Australian Pesticides and Veterinary Medicine Authority, including consideration of all information available on potential impacts to native animals.

  • Even predatory animals that eat rabbits that have died from RHDV1 K5 do not develop an infection.

Protection measures for pet rabbits 

Owners should seek advice from their veterinarian regarding vaccination.

Owners should implement biosecurity measures to protect their animals from infection.

RHDV1 K5 is highly contagious. RHDV can be spread by flies and biting insects, and direct rabbit to rabbit contact. Predators feeding on infected rabbit carcasses may excrete viable virus in their faeces.

The virus can also remain in the environment for an extended period and can be transmitted on objects including clothing, fodder and bedding material.

Pet rabbits that are already vaccinated for the existing strain of RHDV1 are likely to be covered for the new strain (K5) and all strains of RHDV1. 

If unvaccinated, rabbit owners should talk to their local veterinarian about vaccination. Studies have shown that the existing RHDV1 vaccine is likely to be effective against the new K5 variant. A detailed summary of field and experimental data into the efficacy of RHDV vaccines can be found on the PestSmart website.

The AVA recommends that rabbits are vaccinated against RHDV (calicivirus) as follows:

  • Kittens: 4, 8, 12 weeks of age, then 6 monthly for life
  • Adults: 2 vaccinations 1 month apart, then 6 monthly for life
  • This protocol is off-label. Cylap is not registered for 6 monthly use or for use against RHDV2.

Australian Veterinary Association advice on biosecurity measures

  • If possible, keep rabbits inside for the next few weeks or until they can be vaccinated and your vet advises it is now safe for them to be outside.
  • Prevent direct and indirect contact between domestic and wild rabbits. Rabbit-proof your backyard to prevent access by wild rabbits.
  • Limit contact between and handling of unfamiliar pet rabbits.
  • Avoid cutting grass and feeding it to rabbits if there is the risk of contamination from wild rabbits.
  • Remove uneaten food on a daily basis.
  • Wash hands with warm soapy water in between handling rabbits that are not normally in contact with each other.
  • Good insect control is vitally important and will help reduce the risks of introduction of both RHDV and myxomatosis. Insect control should include insect proofing the hutch or keeping the rabbits indoors.
  • Infected rabbits should be isolated and any dead rabbits should be disposed of in a manner that will minimise environmental contamination. Contact your local vet for more information.
  • All cages and equipment should be thoroughly cleaned and disinfected. Disinfectants that can be used to decontaminate equipment include 10% bleach, 10% sodium hydroxide, or parvocide disinfectants. Autoclaving will also kill the virus.

Further information

RHDV1 K5 project updates

IACRC web pages healthierlandscapes.org.au