Status: Completed
Start date: 1 July 2018
Completion date: 30 September 2022
Project code: P01-B-001
Species: European rabbits
Download project report (PDF, 3.42 MB)
European rabbits have become Australia’s most widespread and destructive environmental and agricultural vertebrate pest. One way Australia ‘battles the bunny’ is using viruses.
Using inoculation trials, the project team examined how RHDV2 (rabbit haemorrhagic disease virus strain 2) spreads, how fast, how it evolves, how it interacts with other viruses, and whether it would be an effective extra tool for biocontrol. The results, from most trapping sites and in most months, were consistent with other work indicating that RHDV2 is dominant in Australia.
The objectives of this project were:
Experiments have been undertaken to contribute data to understanding the interactions between the different genotypes of RHDV. The experiments involved studying the “protection” afforded by both natural infection and maternal antibodies, as well as studies involving immunity induced by vaccination. These data confirm that; a) the challenge viruses cause extremely high mortality rates (approaching 100%) b) that RHDV2 has a very variable capacity to overcome immunity c) that the K5 strain of RHDV1 has the capacity to overcome immunity to RHDV2 strains in a moderate proportion of rabbits.
RHDV2 virulence trials in both adult and young domestic rabbits are complete, the results are currently being prepared for publication. Trials have commenced into how maternal antibodies protect young rabbits against RHDV2 infection. A humaneness assessment of RHDV2 infections was completed using an established welfare matrix scoring process. The updated welfare assessment will be made available through PestSmart.
Good progress is being made towards a multivalent vaccine and a research permit for use of a prototype monovalent RHDV2 vaccine has been submitted to the AVPMA and is awaiting approval.
A component of the RHDV2 registration package has been prepared for submission to the APVMA.
The virulence of RHDV2 has been assessed in both adult and young laboratory rabbits. Studies investigating the effects of maternal antibodies on RHDV2 infection have commenced in laboratory rabbits.
Assessment of the virulence and welfare impacts of RHDV2 in both adult and young rabbits is almost complete. 100% case fatality rate has been observed in laboratory rabbits, with a short illness duration.
Another project aspect is investigating the effect of maternal immunity on the ability of young rabbits to get infected with RHDV2 – a critical piece of information that will inform the timing of any future applications of RHDV2 as an additional biocide.
This project is supporting research into the potential registration of RHDV2 as a biological agent for control of wild rabbits. It is unclear how the survival of rabbits is influenced by previous infections by one or more strains of RHDV. Understanding these interactions will inform which RHDV strains may be best suited for release at different times of the year and in different parts of Australia. A component of this work has commenced that experimentally assesses the ability of different virus strains to overcome pre-existing immunity to other strains in wild rabbits.
Another component of this project, the development of a prototype monovalent vaccine for RHDV2 is progressing well.
Cox T, Ramsey D, Sawyers E, Campbell S, Matthews J and Elsworth P (2019) The impact of RHDV-K5 on rabbit populations in Australia: an evaluation of citizen science surveys to monitor rabbit abundance. Scientific Reports 9(15229). https://www.nature.com/articles/s41598-019-51847-w
Hall RN, King T, O’Connor T, Read AJ, Arrow J, Trought K, Duckworth J, Piper M and Strive T (2021) Age and infectious dose significantly affect disease progression after RHDV2 infection in naive domestic rabbits. Viruses 13(6), 1184. https://doi.org/10.3390/v13061184
Hall RN, King T, O’Connor TW, Read AJ, Vrankovic S, Piper M and Strive T (2021) Passive immunity against RHDV2 induces protection against disease but not infection Vaccines 9(10), 1197. https://doi.org/10.3390/vaccines9101197
Kerr P, Hall RN and Strive T (2021) Viruses for landscape-scale therapy: Biological control of rabbits in Australia. In ‘Viruses as Therapeutics: Methods in Molecular Biology’ (editor Lucas AR). Humana, New York, NY. https://doi.org/10.1007/978-1-0716-1012-1\_1.
Kerr P and Strive T (2020) Biological control of vertebrates: Myxoma virous and rabbit hemorrhagic disease virus as biological control for rabbits, In ‘Managing Biological and Ecological Systems’ (Fath BD and Jorgensen SE eds). CRC Press. https://doi.org/10.1201/9780429346170
Mahar JE, Jenckel M, Huang N, Smertina E, Holmes EC, Stive T and Hall R (2021) Frequent intergenotypic recombination between the two non-structural genes is a major driver of epidemiological fitness in calicivirus (submitted), https://www.biorxiv.org/content/biorxiv/early/2021/02/18/2021.02.17.431744.full.pdf
O’Connor TW, Read AJ, Hall RN, Strive S and Kirkland PD (2022) Immunological cross-protection between different rabbit haemorrhagic disease viruses: implications for rabbit biocontrol and vaccine development Vaccines 10(5), 666. https://doi.org/10.3390/vaccines10050666
Pacioni C, Vaughan TG, Strive T, Campbell S, Ramsey DL (2021) Field validation of phylodynamic analytical methods for inference on epidemiological processes in wildlife Transboundary and Emerging Diseases 69(3), 1020-1029, https://doi.org/10.1111/tbed.14058
Patel KK, Strive T, Hall RN, Mutze G, Page B, Korcz M, Booth-Remmers M, Smith IL, Huang N, Kovaliski J, Jayasinghe Ellakkala Appuhamilage RMJ and Taggart PL (2002) Cross-protection, infection and case fatality rates in wild European rabbits experimentally challenged with different rabbit haemorrhagic disease viruses Transboundary and Emerging Diseases, https://doi.org/10.1111/tbed.14530
Ramsey D, Cox T, Strive T, Forsyth D, Stuart I, Hall R, Elsworth P and Campbell S (2019) Emerging RHDV2 suppresses the impact of endemic and novel strains of RHDV on wild rabbit populations Journal of Applied Ecology 57(3), 630-641. https://doi.org/10.1111/1365-2664.13548
Strive T, Piper M, Huang N, Mourant R, Kovaliski J, Capucci L, Cox T and Smith I (2020) Retrospective serological analysis reveals presence of the emerging lagovirus RHDV2 in Australia in wild rabbits at least five months prior to its first detection Transboundary and Emerging Diseases 67(2), 822-833. https://doi.org/10.1111/tbed.13403
Taggart PL, Hall RN, Cox TE, Kovaliski J, McLeod SR and Strive T (2022) Changes in virus transmission dynamics following the emergence of RHDV2 shed light on its competitive advantage over previously circulating variants Transboundary and Emerging Diseases, 69, 1118-1130, https://doi.org/10.1111/tbed.14071
Taggart PL, O’Connor TW, Cooke B, Read AJ, Kirkland PD, Sawyers E, West P and Patel K (2022) Good intentions with adverse outcomes when conservation and pest management guidelines are ignored: A case study in rabbit biocontrol Conservation Science and Practice 4(4), 12639. https://doi.org/10.1111/csp2.12639
Ramsey DS, Patel KK, Campbell S, Hall RN, Taggart PL, Strive T (2023) Sustained Impact of RHDV2 on Wild Rabbit Populations across Australia Eight Years after Its Initial Detection Viruses 15, 1159. https://doi.org/10.3390/v15051159
Elfekih S, Metcalfe S, Walsh TK, Cox TE and Strive T (2022) ‘Genomic insights into a population of introduced European rabbits Oryctolagus cuniculus in Australia and the development of genetic resistance to rabbit hemorrhagic disease virus’, Transbound Emerg Dis, 69:895–902, https://doi.org/10.1111/tbed.14030
Hall R, Huang N, Roberts J and Strive T (2019) ‘Carrion flies as sentinels for monitoring lagovirus activity in Australia’, Transboundary and Emerging Diseases, 66(5):2025–2032. https://doi.org/10.1111/tbed.13250
Jenckel, M., Hall, R.N. and Strive, T., 2022. Pathogen profiling of Australian rabbits by metatranscriptomic sequencing. Transboundary and Emerging Diseases, 69(5), pp.e2629-e2640. https://doi.org/10.1111/tbed.14609
Pacioni C, Hall RN, Strive T, Ramsey DSL, Gilland M and Vaughan TG (2022) ‘Comparative epidemiology of rabbit haemorrhagic disease virus strains from viral sequence data’. Viruses, 15(1): 21 https://doi.org/10.3390/v15010021
Strive T and Cox T (2019) ‘Lethal biological control of rabbits – the most powerful tools for landscape-scale mitigation of rabbit impacts in Australia’, Australian Zoologist, 40(1):118–128. https://doi.org/10.7882/AZ.2019.016
