RHD genetic resistance
Project Leader: Dr Brian Cooke, Invasive Animals CRC
Aim: To find out whether Rabbit Haemorrhagic Disease (RHD) will continue to be successful in keeping rabbits low across Australia.
This project provides crucial knowledge for development of future rabbit control plans as it investigates levels of effectiveness of RHD by analysing development of resistance in wild rabbits.
It involves testing wild rabbits from nine sites across south-eastern Australia by challenge with a small quantity of RHDV to detect changes in case mortality rate or survival time indicative of development of genetic resistance.
Associated studies are carried out in South Australia by the Animal and Plant Control Group. They aim to determine whether the calicivirus is also changing genetically, possibly co-evolving in responses to changes in rabbit resistance and assess the effectiveness of making additional releases of RHDV. DNA samples from experimental rabbits are sent to Nantes in France for analysis as a first step towards the identification of genes that may contribute to rabbit resistance.
This work is being supplemented by the supervision of IA CRC-supported PhD student, Mr Peter Elsworth, who is testing rabbits from an additional four sites in central Australia and North Queensland.
Mr Elsworth is testing field virus strains against the initially released Czech-strain virus to see if apparent changes in genome sequence are reflected in virulence changes.
The final project outcome produces recommendations for maximising the benefits of rabbit control, suggesting actions that can be taken on individual farms or at a regional level and also allow longer-term decisions to be made as to whether additional rabbit control methods (for example, new biological control agents) should be sought.
The project directly relates to projects focusing on enhancing RHDV and RHD-Boost.
- Rabbits from nine sites across Australia have been tested and results indicate different levels of resistance related to the past frequency of RHD outbreaks. Comparisons with experimental controls indicated resistance to infection. Specifically, results showed rabbits in some regions are now more resistant to infection with Czech strain 351 RHDV than was previously the case.
- Publication of a wide-ranging review of the current efficacy of RHD as a biological control agent, including an assessment of the future prospects for control based on the rate or evolution of genetic resistance to the disease. It will allow us to assess how much more rabbit control remains to be done and also enable us to calculate the losses that would accrue if rabbits were allowed to return to former numbers.
Dr David Berman (QDNRW), Mr Peter Elsworth, Ms Dallas Powell and John Kovaliski (SA DLWBC).
IA CRC, Australian Wool Innovation, Animal and Plant Control Group, SA Department of Land, Water and Biodiversity Conservation, Western Australian Department of Agriculture, Industry and Investment NSW, Victorian Department of Primary Industries, Queensland Department of Natural Resources and Water, IZS of Brescia, Italy (supplying monoclonal antibodies for ELISAs), INSERM, Nantes, France (analysing rabbit DNA samples).
Cooke BD, Elsworth PG, Berman D, McPhee S, Kovaliski J, Mutze GJ, Sinclair RG, and Capucci L (2007) Rabbit Haemorrhagic Disease: Wild rabbits show resistance to infection with Czech strain-351 RHDV initially released in Australia, Invasive Animals CRC, Canberra.
Richardson BJ, Phillips S, Hayes R, Sindhe S and Cooke BD (2007) Aspects of the biology of the European rabbit (Oryctolagus cuniculus) and rabbit haemorrhagic disease virus (RHDV) in coastal eastern Australia, Wildlife Research 34/407
For further information, contact us.