Healthier landscapes: RHDV1 K5 national release


RELEASE SITES: GALORE HILL

& THE ESPLANADE, PLEASANT HILLS

Healthier landscapes: RHDV1 K5 national release

To combat the threat of rabbits within Australia, the national release of a Korean strain of Rabbit Haemorrhagic Disease Virus, known as RHDV1 K5 is planned to take place during the first week of March, 2017.

This is the first time in 20 years that a new rabbit biocontrol agent is being released into Australia, however RHDV1 K5 is not a new virus; it is a strain of the existing virus already widespread in Australia, commonly known as calicivirus.

More than 600 sites across Australia are involved in the release of RHDV1 K5 and are working closely with Biosecurity Officers in their regions to ensure the best management outcomes.

RHDV1 K5: Frequently asked questions

What is RHDV1 K5? 
RHDV1K5 is a variant of rabbit haemorrhagic disease virus (RHDV1) that causes a fatal haemorrhagic disease in the European rabbit (Oryctolagus cuniculus). It is specific to the European rabbit, and once a rabbit shows symptoms, death is rapid. There is no treatment or cure for rabbit haemorrhagic disease (RHD); however a vaccine for domestic and production rabbits is available.

 

Where will RHDV1 K5 work best? 
We expect RHDV1 K5 to work in all areas where rabbits are found. However, we expect to see the greatest benefits of RHDV1 K5 in the cool-wet regions of the country. An endemic benign virus is found in the cool-wet regions and temporarily protects rabbits from the Czech strain of RHDV1 (released in 1996). RHDV1 K5 can overcome this protection, so it is likely that in these cool-wet regions we will see an improvement in RHDV biocontrol.

 

How is RHDV1 K5 different to the current variant of RHDV1? 
Both variants cause the same disease; however the RHDV1 K5 variant is better adapted to overcome the protective effects of the benign calicivirus detected several years ago in Australian rabbits.

These benign viruses can temporarily protect rabbits from infection with our current variant of RHDV. These benign viruses are predominantly found in the cool-wet regions of Australia, usually areas with higher production and biodiversity values – where typically RHDV has not worked as well as it has in more arid environments. The use of the RHDV1 K5 variant should improve the effectiveness of RHDV in these cool-wet regions and continue to supress rabbit numbers throughout their distribution, particularly in conjunction with other forms of control.

How do rabbits with RHD die? 
Rabbits that are infected with RHDV first develop symptoms anywhere from 24-72 hours after infection and usually succumb within 6-36 hours after the first symptoms appear. Many infected animals show no signs of disease and die suddenly. Some animals may exhibit lethargy or excitement before death. Animals die from the rapid onset of multiple organ failure. Given the short disease time and the sudden death from rapid organ failure, RHDV continues to be one of the most humane control methods for rabbits.

 

If it takes 48 hours to kill the rabbit, doesn’t the rabbit suffer during this time? 
RHDV is one of the more humane methods of controlling wild rabbits. Basically the rabbits end up with ‘cold-like’ symptoms, become lethargic and then die quickly. Post-infection, there is a rise in body temperature lasting up to 24 hours, followed, in 70–90% of cases, by death up to 48 hours after the onset of a fever.

 

What type of knock-down will RHDV1 K5 achieve? 
While exact knockdown figures are unknown, we do not expect to see population reductions like those seen with the release of the Czech strain of RHDV1 (calicivirus) in 1996. We are not releasing into a naïve population like that in 1996. Knockdowns are expected to be conservative, depending on location and susceptibility of the rabbit population to RHDV1 K5.

 

How does RHDV spread naturally? 
RHDV is spread by insect vectors, such as bushflies and blowflies. Direct contact between a rabbit and a rabbit carcass with RHDV is also an avenue of spread. Animals that predate on rabbit carcasses such as foxes, dogs and cats may also excrete the virus in their faeces.

 

Does it affect people or other animals (pet, native wildlife and livestock)? 
In Australia, no variant of RHDV1 has ever been found to cause infection in any other animal except the European rabbit (Oryctolagus cuniculus). Even predatory animals that eat rabbits that have died from RHDV1 do not develop an infection.

 

Monitoring the effectiveness of the RHDV1 K5 release. 
During February, March and April, Lockhart Shire Council staff, in conjunction with Local Land Services staff, will be involved in the monitoring and control of the rabbit population. This will include spotlighting, release of virus via carrots, collection of deceased rabbits, and sampling of internal organs for laboratory testing. For further information, visit: www.pestsmart.org.au or contact Tracey Geppert on 0429 692 986.

Controlling Fruit Flies

By taking effective action to control fruit flies in your home garden you can minimise damage to the fresh fruit and vegetables you produce and contribute to regional management strategies for fruit fly control.

Follow the links below to view fact sheets for suggested control methods of fruit fly.