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Abstract
Viral diseases, whether of animals or humans, are normally considered as problems to be managed. However, in Australia, two viruses have been used as landscape-scale therapeutics to control European rabbits (Oryctolagus cuniculus), the preeminent invasive vertebrate pest species. Rabbits have caused major environmental and agricultural losses and contributed to extinction of native species. It was not until the introduction of Myxoma virus that effective control of this pest was obtained at a continental scale. Subsequent coevolution of rabbit and virus saw a gradual reduction in the effectiveness of biological control that was partially ameliorated by the introduction of the European rabbit flea to act as an additional vector for the virus. In 1995, a completely different virus, Rabbit hemorrhagic disease virus (RHDV), escaped from testing and spread through the Australian rabbit population and again significantly reduced rabbit numbers and environmental impacts. The evolutionary pressures on this virus appear to be producing quite different outcomes to those that occurred with myxoma virus and the emergence and invasion of a novel genotype of RHDV in 2014 have further augmented control. Molecular studies on myxoma virus have demonstrated multiple proteins that manipulate the host innate and adaptive immune response; however the molecular basis of virus attenuation and reversion to virulence are not yet understood.
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2
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Wells K, Fordham DA, Brook BW, Cassey P, Cox T, O'Hara RB, Schwensow NI. Disentangling synergistic disease dynamics: Implications for the viral biocontrol of rabbits. J Anim Ecol 2018; 87:1418-1428. [DOI: 10.1111/1365-2656.12871] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2018] [Accepted: 05/14/2018] [Indexed: 12/15/2022]
Affiliation(s)
- Konstans Wells
- The Environment Institute and School of Biological Sciences The University of Adelaide Adelaide SA Australia
- Environmental Futures Research Institute Griffith University Brisbane QLD Australia
| | - Damien A. Fordham
- The Environment Institute and School of Biological Sciences The University of Adelaide Adelaide SA Australia
- Center for Macroecology, Evolution, and Climate National Museum of Denmark University of Copenhagen Copenhagen Denmark
| | - Barry W. Brook
- The Environment Institute and School of Biological Sciences The University of Adelaide Adelaide SA Australia
- School of Natural Sciences University of Tasmania Hobart TAS Australia
| | - Phillip Cassey
- The Environment Institute and School of Biological Sciences The University of Adelaide Adelaide SA Australia
| | - Tarnya Cox
- Vertebrate Pest Research Unit NSW Department Primary Industries Orange NSW Australia
| | - Robert B. O'Hara
- Department of Mathematical Sciences Norwegian University of Science and Technology Trondheim Norway
| | - Nina I. Schwensow
- The Environment Institute and School of Biological Sciences The University of Adelaide Adelaide SA Australia
- Institute of Evolutionary Ecology and Conservation Genomics University of Ulm Ulm Germany
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3
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Schwensow NI, Detering H, Pederson S, Mazzoni C, Sinclair R, Peacock D, Kovaliski J, Cooke B, Fickel J, Sommer S. Resistance to RHD virus in wild Australian rabbits: Comparison of susceptible and resistant individuals using a genomewide approach. Mol Ecol 2017; 26:4551-4561. [PMID: 28667769 DOI: 10.1111/mec.14228] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2015] [Revised: 06/02/2017] [Accepted: 06/12/2017] [Indexed: 12/20/2022]
Abstract
Deciphering the genes involved in disease resistance is essential if we are to understand host-pathogen coevolutionary processes. The rabbit haemorrhagic disease virus (RHDV) was imported into Australia in 1995 as a biocontrol agent to manage one of the most successful and devastating invasive species, the European rabbit (Oryctolagus cuniculus). During the first outbreaks of the disease, RHDV caused mortality rates of up to 97%. Recently, however, increased genetic resistance to RHDV has been reported. Here, we have aimed to identify genomic differences between rabbits that survived a natural infection with RHDV and those that died in the field using a genomewide next-generation sequencing (NGS) approach. We detected 72 SNPs corresponding to 133 genes associated with survival of a RHD infection. Most of the identified genes have known functions in virus infections and replication, immune responses or apoptosis, or have previously been found to be regulated during RHD. Some of the genes identified in experimental studies, however, did not seem to play a role under natural selection regimes, highlighting the importance of field studies to complement the genomic background of wildlife diseases. Our study provides a set of candidate markers as a tool for the future scanning of wild rabbits for their resistance to RHDV. This is important both for wild rabbit populations in southern Europe where RHD is regarded as a serious problem decimating the prey of endangered predator species and for assessing the success of currently planned RHDV variant biocontrol releases in Australia.
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Affiliation(s)
- Nina I Schwensow
- Institute of Evolutionary Ecology and Conservation Genomics, University of Ulm, Ulm, Germany.,School of Biological Sciences, University of Adelaide, Adelaide, SA, Australia
| | - Harald Detering
- Berlin Center for Genomics in Biodiversity Research, Berlin, Germany.,Department of Biochemistry, Genetics and Immunology and Biomedical Research Center (CINBIO), University of Vigo, Vigo, Spain
| | - Stephen Pederson
- Bioinformatics Hub, School of Biological Sciences, University of Adelaide, Adelaide, SA, Australia
| | - Camila Mazzoni
- Berlin Center for Genomics in Biodiversity Research, Berlin, Germany.,Department of Evolutionary Genetics, Leibniz Institute for Zoo and Wildlife Research (IZW), Berlin, Germany
| | - Ron Sinclair
- School of Biological Sciences, University of Adelaide, Adelaide, SA, Australia
| | | | | | - Brian Cooke
- Institute for Applied Ecology, University of Canberra, Canberra, ACT, Australia
| | - Jörns Fickel
- Department of Evolutionary Genetics, Leibniz Institute for Zoo and Wildlife Research (IZW), Berlin, Germany.,Molecular Ecology & Evolution, Institute for Biochemistry and Biology, Potsdam University, Potsdam, Germany
| | - Simone Sommer
- Institute of Evolutionary Ecology and Conservation Genomics, University of Ulm, Ulm, Germany
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4
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DIFFERENT SEROLOGICAL PROFILES TO CO-OCCURRING PATHOGENIC AND NONPATHOGENIC CALICIVIRUSES IN WILD EUROPEAN RABBITS (ORYCTOLAGUS CUNICULUS) ACROSS AUSTRALIA. J Wildl Dis 2017; 53:472-481. [PMID: 28231031 DOI: 10.7589/2016-06-148] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Rabbit hemorrhagic disease virus (RHDV) was released in Australia as a biocontrol agent for wild European rabbits ( Oryctolagus cuniculus ) in 1995-96; however, its effects were variable across Australia with the greatest population reductions seen in lower annual rainfall areas (<400 mm). There is speculation that the reduced effectiveness observed at higher annual rainfall sites is at least partially due to the presence of a nonpathogenic calicivirus (RCV-A1). The RCV-A1 is related to RHDV and confers partial and transient protection against lethal RHDV infection in laboratory tests. What is not well understood is where, how, and to what degree RCV-A1 impedes the effect of RHDV-mediated rabbit control under field conditions. We investigated seven wild rabbit populations across six states and territories representing different seasonal rainfall zones across Australia, four times during 2011-12, to investigate if the presence and prevalence of RCV-A1 coincided with a change in RHDV immunity status within these populations. Besides serology, tissue samples from both trapped and shot rabbits were collected for virus detection by reverse transcription PCR. Overall, 52% (n=258) of the total samples (n=496) tested positive for RHDV antibodies and 42% (n=208) positive for RCV-A1 antibodies; 30% (n=150) of the sera contained antibodies to both viruses. The proportion of rabbits with RHDV antibodies increased significantly at sites where RCV-A1 antibodies were present (χ21, α=0.1, P<0.001). Evidence that preinfection of RCV-A1 may lead to a higher proportion of sampled rabbits with antibodies to both viruses was found at only one site.
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Velarde R, Cavadini P, Neimanis A, Cabezón O, Chiari M, Gaffuri A, Lavín S, Grilli G, Gavier-Widén D, Lavazza A, Capucci L. Spillover Events of Infection of Brown Hares (Lepus europaeus) with Rabbit Haemorrhagic Disease Type 2 Virus (RHDV2) Caused Sporadic Cases of an European Brown Hare Syndrome-Like Disease in Italy and Spain. Transbound Emerg Dis 2016; 64:1750-1761. [PMID: 27615998 PMCID: PMC5697611 DOI: 10.1111/tbed.12562] [Citation(s) in RCA: 69] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2016] [Indexed: 12/17/2022]
Abstract
Rabbit haemorrhagic disease virus (RHDV) is a lagovirus that can cause fatal hepatitis (rabbit haemorrhagic disease, RHD) with mortality of 80–90% in farmed and wild rabbits. Since 1986, RHDV has caused outbreaks in rabbits (Oryctolagus cuniculus) in Europe, but never in European brown hares (Lepus europaeus, EBH). In 2010, a new RHDV‐related virus, called RHDV2, emerged in Europe, causing extended epidemics because it largely overcame the immunity to RHDV present in most rabbit populations. RHDV2 also was identified in Cape hare (Lepus capensis subsp. mediterraneus) and in Italian hare (Lepus corsicanus). Here, we describe two distinct incidents of RHDV2 infection in EBH that occurred in Italy (2012) and Spain (2014). The two RHDV2 strains caused macroscopic and microscopic lesions similar to European brown hare syndrome (EBHS) in hares, and they were genetically related to other RHDV2 strains in Europe. EBHs are common in Europe, often sharing habitat with rabbits. They likely have been exposed to high levels of RHDV2 during outbreaks in rabbits in recent years, yet only two incidents of RHDV2 in EBHs have been found in Italy and Spain, suggesting that EBHs are not a primary host. Instead, they may act as spillover hosts in situations when infection pressure is high and barriers between rabbits and hares are limited, resulting in occasional infections causing EBHS‐like lesions. The serological survey of stocked hare sera taken from Italian and Spanish hare populations provided an understanding of naturally occurring RHDV2 infection in the field confirming its sporadic occurrence in EBH. Our findings increase the knowledge on distribution, host range and epidemiology of RHDV2.
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Affiliation(s)
- R Velarde
- Servei d'Ecopatologia de Fauna Salvatge (SEFaS), Departament de Medicina i Cirurgia Animals, Universitat Autònoma de Barcelona (UAB), Bellaterra, Barcelona, Spain
| | - P Cavadini
- Istituto Zooprofilattico Sperimentale della Lombardia e dell'Emilia Romagna 'Bruno Ubertini' (IZSLER), OIE Reference Laboratory for Rabbit Haemorrhagic Disease, Brescia, Italy
| | - A Neimanis
- Department of Pathology and Wildlife Disease, National Veterinary Institute (SVA), Uppsala, Sweden.,Department of Biomedical Sciences and Veterinary Public Health, University of Agricultural Sciences, Uppsala, Sweden
| | - O Cabezón
- Servei d'Ecopatologia de Fauna Salvatge (SEFaS), Departament de Medicina i Cirurgia Animals, Universitat Autònoma de Barcelona (UAB), Bellaterra, Barcelona, Spain.,IRTA, Centre de Recerca en Sanitat Animal (CReSA, IRTA-UAB), Campus de la Universitat Autònoma de Barcelona, Bellaterra, Spain
| | - M Chiari
- Istituto Zooprofilattico Sperimentale della Lombardia e dell'Emilia Romagna 'Bruno Ubertini' (IZSLER), OIE Reference Laboratory for Rabbit Haemorrhagic Disease, Brescia, Italy
| | - A Gaffuri
- Istituto Zooprofilattico Sperimentale della Lombardia e dell'Emilia Romagna 'Bruno Ubertini' (IZSLER), OIE Reference Laboratory for Rabbit Haemorrhagic Disease, Brescia, Italy
| | - S Lavín
- Servei d'Ecopatologia de Fauna Salvatge (SEFaS), Departament de Medicina i Cirurgia Animals, Universitat Autònoma de Barcelona (UAB), Bellaterra, Barcelona, Spain
| | - G Grilli
- Dipartimento di Medicina Veterinaria, Università degli Studi di Milano, Milan, Italy
| | - D Gavier-Widén
- Department of Pathology and Wildlife Disease, National Veterinary Institute (SVA), Uppsala, Sweden.,Department of Biomedical Sciences and Veterinary Public Health, University of Agricultural Sciences, Uppsala, Sweden
| | - A Lavazza
- Istituto Zooprofilattico Sperimentale della Lombardia e dell'Emilia Romagna 'Bruno Ubertini' (IZSLER), OIE Reference Laboratory for Rabbit Haemorrhagic Disease, Brescia, Italy
| | - L Capucci
- Istituto Zooprofilattico Sperimentale della Lombardia e dell'Emilia Romagna 'Bruno Ubertini' (IZSLER), OIE Reference Laboratory for Rabbit Haemorrhagic Disease, Brescia, Italy
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6
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Liu J, Fordham DA, Cooke BD, Cox T, Mutze G, Strive T. Distribution and prevalence of the Australian non-pathogenic rabbit calicivirus is correlated with rainfall and temperature. PLoS One 2014; 9:e113976. [PMID: 25486092 PMCID: PMC4259302 DOI: 10.1371/journal.pone.0113976] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2014] [Accepted: 11/02/2014] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND Australia relies heavily on rabbit haemorrhagic disease virus (RHDV) for the biological control of introduced European wild rabbits Oryctolagus cuniculus, which are significant economic and environmental pests. An endemic non-pathogenic rabbit calicivirus termed RCV-A1 also occurs in wild rabbits in Australian and provides partial protection against lethal RHDV infection, thus interfering with effective rabbit control. Despite its obvious importance for rabbit population management, little is known about the epidemiology of this benign rabbit calicivirus. METHODS We determined the continent-wide distribution and prevalence of RCV-A1 by analysing 1,805 serum samples from wild rabbit populations at 78 sites across Australia for the presence of antibodies to RCV-A1 using a serological test that specifically detects RCV-A1 antibodies and does not cross-react with co-occurring RHDV antibodies. We also investigated possible correlation between climate variables and prevalence of RCV-A1 by using generalised linear mixed effect models. RESULTS Antibodies to RCV-A1 were predominantly detected in rabbit populations in cool, high rainfall areas of the south-east and south-west of the continent. There was strong support for modelling RCV-A1 prevalence as a function of average annual rainfall and minimum temperature. The best ranked model explained 26% of the model structural deviance. According to this model, distribution and prevalence of RCV-A1 is positively correlated with periods of above average rainfall and negatively correlated with periods of drought. IMPLICATIONS Our statistical model of RCV-A1 prevalence will greatly increase our understanding of RCV-A1 epidemiology and its interaction with RHDV in Australia. By defining the environmental conditions associated with the prevalence of RCV-A1, it also contributes towards understanding the distribution of similar viruses in New Zealand and Europe.
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Affiliation(s)
- June Liu
- Commonwealth Scientific and Industrial Research Organisation, Ecosystem Sciences Division, Canberra, Australian Capital Territory 2601, Australia
- Invasive Animals Cooperative Research Centre, University of Canberra, Canberra, Australian Capital Territory 2601, Australia
| | - Damien A. Fordham
- The Environment Institute and School of Earth and Environmental Sciences, University of Adelaide, Adelaide, South Australia 5005, Australia
| | - Brian D. Cooke
- Institute of Applied Ecology, University of Canberra, Canberra, Australian Capital Territory 2601, Australia
- Invasive Animals Cooperative Research Centre, University of Canberra, Canberra, Australian Capital Territory 2601, Australia
| | - Tarnya Cox
- Invasive Animals Cooperative Research Centre, University of Canberra, Canberra, Australian Capital Territory 2601, Australia
- Vertebrate Pest Research Unit, NSW Department Primary Industries, Orange, New South Wales 2800, Australia
| | - Greg Mutze
- Natural Resources Management Biosecurity Unit, Department of Water, Land and Biodiversity Conservation, Adelaide, South Australia 5001, Australia
| | - Tanja Strive
- Commonwealth Scientific and Industrial Research Organisation, Ecosystem Sciences Division, Canberra, Australian Capital Territory 2601, Australia
- Invasive Animals Cooperative Research Centre, University of Canberra, Canberra, Australian Capital Territory 2601, Australia
- * E-mail:
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7
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Elsworth P, Cooke BD, Kovaliski J, Sinclair R, Holmes EC, Strive T. Increased virulence of rabbit haemorrhagic disease virus associated with genetic resistance in wild Australian rabbits (Oryctolagus cuniculus). Virology 2014; 464-465:415-423. [PMID: 25146599 DOI: 10.1016/j.virol.2014.06.037] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2014] [Revised: 06/10/2014] [Accepted: 06/12/2014] [Indexed: 01/14/2023]
Abstract
The release of myxoma virus (MYXV) and Rabbit Haemorrhagic Disease Virus (RHDV) in Australia with the aim of controlling overabundant rabbits has provided a unique opportunity to study the initial spread and establishment of emerging pathogens, as well as their co-evolution with their mammalian hosts. In contrast to MYXV, which attenuated shortly after its introduction, rapid attenuation of RHDV has not been observed. By studying the change in virulence of recent field isolates at a single field site we show, for the first time, that RHDV virulence has increased through time, likely because of selection to overcome developing genetic resistance in Australian wild rabbits. High virulence also appears to be favoured as rabbit carcasses, rather than diseased animals, are the likely source of mechanical insect transmission. These findings not only help elucidate the co-evolutionary interaction between rabbits and RHDV, but reveal some of the key factors shaping virulence evolution.
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Affiliation(s)
- Peter Elsworth
- Robert Wicks Pest Animal Research Centre, Biosecurity Queensland, Department of Agriculture, Fisheries and Forestry, Toowoomba, Queensland, Australia; Invasive Animals Cooperative Research Centre, University of Canberra, Bruce, ACT, Canberra, Australia
| | - Brian D Cooke
- Invasive Animals Cooperative Research Centre, University of Canberra, Bruce, ACT, Canberra, Australia; University of Canberra, Institute for Applied Ecology, ACT, Canberra, Australia
| | - John Kovaliski
- Invasive Animals Cooperative Research Centre, University of Canberra, Bruce, ACT, Canberra, Australia; Biosecurity South Australia, Adelaide, South Australia, Australia
| | - Ronald Sinclair
- Invasive Animals Cooperative Research Centre, University of Canberra, Bruce, ACT, Canberra, Australia; Biosecurity South Australia, Adelaide, South Australia, Australia
| | - Edward C Holmes
- Marie Bashir Institute for Infectious Diseases & Biosecurity, Charles Perkins Centre, School of Biological Sciences and Sydney Medical School, The University of Sydney, Sydney, New South Wales 2006, Australia
| | - Tanja Strive
- Invasive Animals Cooperative Research Centre, University of Canberra, Bruce, ACT, Canberra, Australia; CSIRO Ecosystem Sciences, Canberra, ACT, Australia; CSIRO Biosecurity Flagship, Canberra, Australia.
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8
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Matthaei M, Kerr PJ, Read AJ, Hick P, Haboury S, Wright JD, Strive T. Comparative quantitative monitoring of rabbit haemorrhagic disease viruses in rabbit kittens. Virol J 2014; 11:109. [PMID: 24913134 PMCID: PMC4060863 DOI: 10.1186/1743-422x-11-109] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2014] [Accepted: 05/23/2014] [Indexed: 12/31/2022] Open
Abstract
Background Only one strain (the Czech CAPM-v351) of rabbit haemorrhagic disease virus (RHDV) has been released in Australia and New Zealand to control pest populations of the European rabbit O. cuniculus. Antigenic variants of RHDV known as RHDVa strains are reportedly replacing RHDV strains in other parts of the world, and Australia is currently investigating the usefulness of RHDVa to complement rabbit biocontrol efforts in Australia and New Zealand. RHDV efficiently kills adult rabbits but not rabbit kittens, which are more resistant to RHD the younger they are and which may carry the virus without signs of disease for prolonged periods. These different infection patterns in young rabbits may significantly influence RHDV epidemiology in the field and hence attempts to control rabbit numbers. Methods We quantified RHDV replication and shedding in 4–5 week old rabbits using quantitative real time PCR to assess their potential to shape RHDV epidemiology by shedding and transmitting virus. We further compared RHDV-v351 with an antigenic variant strain of RHDVa in kittens that is currently being considered as a potential RHDV strain for future release to improve rabbit biocontrol in Australia. Results Kittens were susceptible to infection with virus doses as low as 10 ID50. Virus growth, shedding and transmission after RHDVa infection was found to be comparable or non-significantly lower compared to RHDV. Virus replication and shedding was observed in all kittens infected, but was low in comparison to adult rabbits. Both viruses were shed and transmitted to bystander rabbits. While blood titres indicated that 4–5 week old kittens mostly clear the infection even in the absence of maternal antibodies, virus titres in liver, spleen and mesenteric lymph node were still high on day 5 post infection. Conclusions Rabbit kittens are susceptible to infection with very low doses of RHDV, and can transmit virus before they seroconvert. They may therefore play an important role in RHDV field epidemiology, in particular for virus transmission within social groups during virus outbreaks.
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Affiliation(s)
| | | | | | | | | | | | - Tanja Strive
- Commonwealth Scientific and Industrial Research Organisation - Ecosystem Sciences, ACT 2601 Black Mountain, Australia.
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9
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Mutze G, Bird P, Jennings S, Peacock D, de Preu N, Kovaliski J, Cooke B, Capucci L. Recovery of South Australian rabbit populations from the impact of rabbit haemorrhagic disease. WILDLIFE RESEARCH 2014. [DOI: 10.1071/wr14107] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Context
Recovery of Australian rabbit populations from the impact of rabbit haemorrhagic disease virus (RHDV) contrasts with more prolonged suppression of wild rabbits in Europe, and has been widely discussed in the scientific community, but not yet documented in formal scientific literature. The underlying causes of recovery remain unclear, but resistance to RHDV infection has been reported in laboratory studies of wild-caught rabbits.
Aims
We document numerical changes in two South Australian wild rabbit populations that were initially suppressed by RHDV, and examine serological data to evaluate several alternative hypotheses for the cause of recovery.
Methods
Rabbit numbers were assessed from spotlight transect counts and dung mass transects between 1991 and 2011, and age and RHDV antibody sero-prevalence were estimated from rabbits shot in late summer.
Key results
Rabbit numbers were heavily suppressed by RHDV between 1995 and 2002, then increased 5- to 10-fold between 2003 and 2010. During the period of increase, annual RHDV infection rates remained stable or increased slightly, average age of rabbits remained stable and annual rainfall was below average.
Conclusions
Rabbit populations recovered but neither avoidance of RHDV infection, gradual accumulation of long-lived RHD-immune rabbits, nor high pasture productivity were contributing factors. This leaves increased annual survival from RHDV infection as the most likely cause of recovery.
Implications
Previously documented evidence of resistance to RHDV infection may be of little consequence to post-RHD recovery in rabbit numbers, unless the factors that influence the probability of infection also shape the course of infection and affect survival of infected rabbits.
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Kovaliski J, Sinclair R, Mutze G, Peacock D, Strive T, Abrantes J, Esteves PJ, Holmes EC. Molecular epidemiology of Rabbit Haemorrhagic Disease Virus in Australia: when one became many. Mol Ecol 2013; 23:408-20. [PMID: 24251353 DOI: 10.1111/mec.12596] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2013] [Revised: 11/06/2013] [Accepted: 11/13/2013] [Indexed: 12/20/2022]
Abstract
Rabbit Haemorrhagic Disease Virus (RHDV) was introduced into Australia in 1995 as a biological control agent against the wild European rabbit (Oryctolagus cuniculus). We evaluated its evolution over a 16-year period (1995-2011) by examining 50 isolates collected throughout Australia, as well as the original inoculum strains. Phylogenetic analysis of capsid protein VP60 sequences of the Australian isolates, compared with those sampled globally, revealed that they form a monophyletic group with the inoculum strains (CAPM V-351 and RHDV351INOC). Strikingly, despite more than 3000 rereleases of RHDV351INOC since 1995, only a single viral lineage has sustained its transmission in the long-term, indicative of a major competitive advantage. In addition, we find evidence for widespread viral gene flow, in which multiple lineages entered individual geographic locations, resulting in a marked turnover of viral lineages with time, as well as a continual increase in viral genetic diversity. The rate of RHDV evolution recorded in Australia -4.0 (3.3-4.7) × 10(-3) nucleotide substitutions per site per year - was higher than previously observed in RHDV, and evidence for adaptive evolution was obtained at two VP60 residues. Finally, more intensive study of a single rabbit population (Turretfield) in South Australia provided no evidence for viral persistence between outbreaks, with genetic diversity instead generated by continual strain importation.
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Affiliation(s)
- John Kovaliski
- NRM Biosecurity, Biosecurity South Australia, PO Box 1671, Adelaide, SA, 5001, Australia.,Invasive Animals Cooperative Research Centre, University of Canberra, Canberra, ACT, 2601, Australia
| | - Ron Sinclair
- NRM Biosecurity, Biosecurity South Australia, PO Box 1671, Adelaide, SA, 5001, Australia.,Invasive Animals Cooperative Research Centre, University of Canberra, Canberra, ACT, 2601, Australia
| | - Greg Mutze
- NRM Biosecurity, Biosecurity South Australia, PO Box 1671, Adelaide, SA, 5001, Australia.,Invasive Animals Cooperative Research Centre, University of Canberra, Canberra, ACT, 2601, Australia
| | - David Peacock
- NRM Biosecurity, Biosecurity South Australia, PO Box 1671, Adelaide, SA, 5001, Australia.,Invasive Animals Cooperative Research Centre, University of Canberra, Canberra, ACT, 2601, Australia
| | - Tanja Strive
- Invasive Animals Cooperative Research Centre, University of Canberra, Canberra, ACT, 2601, Australia.,CSIRO Ecosystem Sciences, Black Mountain Laboratories, Clunies Ross Street, Black Mountain, ACT, 2601, Australia
| | - Joana Abrantes
- CIBIO/UP Centro de Investigação em Biodiversidade e Recursos Genéticos/Universidade do Porto, InBio, Laboratório Associado, Campus Agrário de Vairão, R. Padre Armando Quintas, 4485-661, Vairão, Portugal.,INSERM, U892, Université de Nantes, Nantes, France
| | - Pedro J Esteves
- INSERM, U892, Université de Nantes, Nantes, France.,CITS, Centro de Investigação em Tecnologias da Saúde, IPSN, CESPU, Gandra, Portugal
| | - Edward C Holmes
- Marie Bashir Institute for Infectious Diseases and Biosecurity, School of Biological Sciences and Sydney Medical School, The University of Sydney, Sydney, NSW, 2006, Australia
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11
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Strive T, Elsworth P, Liu J, Wright JD, Kovaliski J, Capucci L. The non-pathogenic Australian rabbit calicivirus RCV-A1 provides temporal and partial cross protection to lethal Rabbit Haemorrhagic Disease Virus infection which is not dependent on antibody titres. Vet Res 2013; 44:51. [PMID: 23834204 PMCID: PMC3733936 DOI: 10.1186/1297-9716-44-51] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2012] [Accepted: 06/12/2013] [Indexed: 02/06/2023] Open
Abstract
The endemic non-pathogenic Australian rabbit calicivirus RCV-A1 is known to provide some cross protection to lethal infection with the closely related Rabbit Haemorrhagic Disease Virus (RHDV). Despite its obvious negative impacts on viral biocontrol of introduced European rabbits in Australia, little is known about the extent and mechanisms of this cross protection. In this study 46 rabbits from a colony naturally infected with RCV-A1 were exposed to RHDV. Survival rates and survival times did not correlate with titres of serum antibodies specific to RCV-A1 or cross reacting to RHDV, but were instead influenced by the time between infection with the two viruses, demonstrating for the first time that the cross protection to lethal RHDV infection is transient. These findings are an important step towards a better understanding of the complex interactions of co-occurring pathogenic and non-pathogenic lagoviruses.
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Affiliation(s)
- Tanja Strive
- Division of Ecosystem Sciences, Commonwealth Scientific and Industrial Research Organisation, Canberra ACT 2601, Australia.
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12
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Abstract
Viral diseases of rabbits have been used historically to study oncogenesis (e.g. rabbit fibroma virus, cottontail rabbit papillomavirus) and biologically to control feral rabbit populations (e.g. myxoma virus). However, clinicians seeing pet rabbits in North America infrequently encounter viral diseases although myxomatosis may be seen occasionally. The situation is different in Europe and Australia, where myxomatosis and rabbit hemorrhagic disease are endemic. Advances in epidemiology and virology have led to detection of other lapine viruses that are now recognized as agents of emerging infectious diseases. Rabbit caliciviruses, related to rabbit hemorrhagic disease, are generally avirulent, but lethal variants are being identified in Europe and North America. Enteric viruses including lapine rotavirus, rabbit enteric coronavirus and rabbit astrovirus are being acknowledged as contributors to the multifactorial enteritis complex of juvenile rabbits. Three avirulent leporid herpesviruses are found in domestic rabbits. A fourth highly pathogenic virus designated leporid herpesvirus 4 has been described in Canada and Alaska. This review considers viruses affecting rabbits by their clinical significance. Viruses of major and minor clinical significance are described, and viruses of laboratory significance are mentioned.
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Affiliation(s)
- Peter J. Kerr
- CSIRO Entomology, GPO Box 1700, Canberra, ACT 2601, Australia
| | - Thomas M. Donnelly
- The Kenneth S. Warren Institute, 712 Kitchawan Road, Ossining, NY 10562, USA
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Liu J, Kerr PJ, Strive T. A sensitive and specific blocking ELISA for the detection of rabbit calicivirus RCV-A1 antibodies. Virol J 2012; 9:182. [PMID: 22943557 PMCID: PMC3493337 DOI: 10.1186/1743-422x-9-182] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2012] [Accepted: 08/28/2012] [Indexed: 12/17/2022] Open
Abstract
BACKGROUND Antibodies to non-pathogenic rabbit caliciviruses (RCVs) cross-react in serological tests for rabbit hemorrhagic disease virus (RHDV) and vice versa, making epidemiological studies very difficult where both viruses occur. It is important to understand the distribution and interaction of the two viruses because the highly pathogenic RHDV has been used as a biocontrol agent for wild rabbits in Australia and New Zealand for the past 17 years. The presence of the benign RCV Australia 1 (RCV-A1) is considered a key factor for the failure of RHDV mediated rabbit control in cooler, wetter areas of Australia. RESULTS A highly sensitive and specific blocking ELISA was developed for the detection of RCV-A1 antibodies. When sera from rabbits with a known infection history for either RCV-A1 or RHDV were tested, this assay showed 100% sensitivity and no cross-reactivity with RHDV sera (100% specificity). CONCLUSIONS This new ELISA not only allows the detection of RCV-A1 at a population level, but also permits the serological status of individual rabbits to be determined more reliably than previously described methods. This robust and simple to perform assay is therefore the tool of choice for studying RCV-A1 epidemiology in Australian wild rabbit populations.
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Affiliation(s)
- June Liu
- Commonwealth Scientific and Industrial Research Organisation, Ecosystem Sciences Division, GPO Box 1700, Canberra ACT, 2601, Australia
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Liu J, Kerr PJ, Wright JD, Strive T. Serological assays to discriminate rabbit haemorrhagic disease virus from Australian non-pathogenic rabbit calicivirus. Vet Microbiol 2012; 157:345-54. [DOI: 10.1016/j.vetmic.2012.01.018] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2011] [Revised: 01/17/2012] [Accepted: 01/19/2012] [Indexed: 10/14/2022]
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Abrantes J, van der Loo W, Le Pendu J, Esteves PJ. Rabbit haemorrhagic disease (RHD) and rabbit haemorrhagic disease virus (RHDV): a review. Vet Res 2012; 43:12. [PMID: 22325049 PMCID: PMC3331820 DOI: 10.1186/1297-9716-43-12] [Citation(s) in RCA: 262] [Impact Index Per Article: 21.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2011] [Accepted: 02/10/2012] [Indexed: 02/06/2023] Open
Abstract
Rabbit haemorrhagic disease virus (RHDV) is a calicivirus of the genus Lagovirus that causes rabbit haemorrhagic disease (RHD) in adult European rabbits (Oryctolagus cuniculus). First described in China in 1984, the virus rapidly spread worldwide and is nowadays considered as endemic in several countries. In Australia and New Zealand where rabbits are pests, RHDV was purposely introduced for rabbit biocontrol. Factors that may have precipitated RHD emergence remain unclear, but non-pathogenic strains seem to pre-date the appearance of the pathogenic strains suggesting a key role for the comprehension of the virus origins. All pathogenic strains are classified within one single serotype, but two subtypes are recognised, RHDV and RHDVa. RHD causes high mortality in both domestic and wild adult animals, with individuals succumbing between 48-72 h post-infection. No other species has been reported to be fatally susceptible to RHD. The disease is characterised by acute necrotising hepatitis, but haemorrhages may also be found in other organs, in particular the lungs, heart, and kidneys due to disseminated intravascular coagulation. Resistance to the disease might be explained in part by genetically determined absence or weak expression of attachment factors, but humoral immunity is also important. Disease control in rabbitries relies mainly on vaccination and biosecurity measures. Such measures are difficult to be implemented in wild populations. More recent research has indicated that RHDV might be used as a molecular tool for therapeutic applications. Although the study of RHDV and RHD has been hampered by the lack of an appropriate cell culture system for the virus, several aspects of the replication, epizootology, epidemiology and evolution have been disclosed. This review provides a broad coverage and description of the current knowledge on the disease and the virus.
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Affiliation(s)
- Joana Abrantes
- CIBIO/UP, Centro de Investigacao em Biodiversidade e Recursos Geneticos/Universidade do Porto, Campus Agrario de Vairao, 4485-661 Vairao, Portugal
- INSERM, U892, Université de Nantes, 44007 Nantes, France
| | - Wessel van der Loo
- CIBIO/UP, Centro de Investigacao em Biodiversidade e Recursos Geneticos/Universidade do Porto, Campus Agrario de Vairao, 4485-661 Vairao, Portugal
| | | | - Pedro J Esteves
- CIBIO/UP, Centro de Investigacao em Biodiversidade e Recursos Geneticos/Universidade do Porto, Campus Agrario de Vairao, 4485-661 Vairao, Portugal
- CITS, Centro de Investigacao em Tecnologias de Saude, CESPU, Gandra, Portugal
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Rabbit haemorrhagic disease: are Australian rabbits (Oryctolagus cuniculus) evolving resistance to infection with Czech CAPM 351 RHDV? Epidemiol Infect 2012; 140:1972-81. [PMID: 22244198 DOI: 10.1017/s0950268811002743] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Rabbit haemorrhagic disease is a major tool for the management of introduced, wild rabbits in Australia. However, new evidence suggests that rabbits may be developing resistance to the disease. Rabbits sourced from wild populations in central and southeastern Australia, and domestic rabbits for comparison, were experimentally challenged with a low 60 ID50 oral dose of commercially available Czech CAPM 351 virus - the original strain released in Australia. Levels of resistance to infection were generally higher than for unselected domestic rabbits and also differed (0-73% infection rates) between wild populations. Resistance was lower in populations from cooler, wetter regions and also low in arid regions with the highest resistance seen within zones of moderate rainfall. These findings suggest the external influences of non-pathogenic calicivirus in cooler, wetter areas and poor recruitment in arid populations may influence the development rate of resistance in Australia.
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Cabezas S, Calvete C, Moreno S. Survival of translocated wild rabbits: importance of habitat, physiological and immune condition. Anim Conserv 2011. [DOI: 10.1111/j.1469-1795.2011.00472.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Zheng T, Parkes JP. Rabbit haemorrhagic disease: advantages of cELISA in assessing immunity in wild rabbits (Oryctolagus cuniculus). Vet Microbiol 2011; 153:387-92. [PMID: 21719216 DOI: 10.1016/j.vetmic.2011.05.049] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2011] [Revised: 05/26/2011] [Accepted: 05/31/2011] [Indexed: 11/30/2022]
Abstract
Rabbit haemorrhagic disease (RHD) is an acute fatal disease of domestic and wild European rabbits (Oryctolagus cuniculus) caused by RHD virus (RHDV). Accurate assessment of immunity is of great importance for the conservation and control of wild rabbits. We evaluated a competitive ELISA (cELISA) against isotype ELISAs for assessing the protective immunity against the disease by challenging 50 wild-caught rabbits with a lethal dose of RHDV. Death or survival to the challenge was used as a criterion to determine the performance characteristics of the assay for the assessment of immunity in rabbits. At 1:10 dilution, a serum exhibiting ≥ 25% inhibition (1:10(25)) was regarded as the presence of RHDV-specific antibodies. Eleven of 16 (68.8%) rabbits with antibodies at 1:10(25) (<1:40) died of RHD. When the cut-off was moved from 25% to 50% inhibition (1:10(50)) at 1:10 serum dilution, the assay sensitivity, specificity and accuracy for the protective immunity were improved from 84%, 54.2% and 69.4% to 84%, 100% and 91.8%, respectively. We also demonstrated at the epitope amino acid sequence level why the presence of the RHDV-cross reactive benign rabbit calicivirus, which interfered with isotype ELISAs, had little impact on the specificity of the cELISA for the diagnosis of RHDV infection. The presence of RHDV-specific antibody at 1:10(50) by the cELISA is a reliable indicator for the protective immunity. In contrast to isotype ELISAs, the cELISA is a valuable specific tool for monitoring the herd immunity to RHD for the conservation and management of wild rabbits in the field.
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Affiliation(s)
- Tao Zheng
- AgResearch Grasslands, Hopkirk Research Institute, Private Bag 11008, Palmerston North 4442, New Zealand.
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Le Gall-Reculé G, Zwingelstein F, Fages MP, Bertagnoli S, Gelfi J, Aubineau J, Roobrouck A, Botti G, Lavazza A, Marchandeau S. Characterisation of a non-pathogenic and non-protective infectious rabbit lagovirus related to RHDV. Virology 2010; 410:395-402. [PMID: 21195443 DOI: 10.1016/j.virol.2010.12.001] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2010] [Revised: 10/03/2010] [Accepted: 12/03/2010] [Indexed: 11/17/2022]
Abstract
The existence of non-pathogenic RHDV strains was established when a non-lethal virus named rabbit calicivirus (RCV) was characterised in 1996 in Italy. Since then, different RNA sequences related to RHDV have been detected in apparently healthy domestic and wild rabbits, and recently a new lagovirus was identified in Australia. We have characterised from seropositive healthy domestic rabbits a non-lethal lagovirus that differs from RHDV in terms of pathogenicity, tissue tropism and capsid protein sequence. Phylogenetic analyses have revealed that it is close to the Ashington strain and to the RCV, but distinct. We proved experimentally that it is infectious but non-pathogenic and demonstrated that, contrary to the other described non-pathogenic lagoviruses, it induces antibodies that do not protect against RHDV. Our results indicate the existence of a gradient of cross-protection between circulating strains, from non-protective, partially protective to protective strains, and highlight the extent of diversity within the genus Lagovirus.
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Affiliation(s)
- Ghislaine Le Gall-Reculé
- French Agency for Food, Environmental and Occupational Health Safety (Anses), Laboratory for Studies and Research on Poultry, Pig and Fish Farming (LERAPP), UVIPAC, BP 53, F-22440 Ploufragan, France.
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Mutze G, Kovaliski J, Butler K, Capucci L, McPhee S. The effect of rabbit population control programmes on the impact of rabbit haemorrhagic disease in south-eastern Australia. J Appl Ecol 2010. [DOI: 10.1111/j.1365-2664.2010.01844.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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Strive T, Wright J, Kovaliski J, Botti G, Capucci L. The non-pathogenic Australian lagovirus RCV-A1 causes a prolonged infection and elicits partial cross-protection to rabbit haemorrhagic disease virus. Virology 2010; 398:125-34. [DOI: 10.1016/j.virol.2009.11.045] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2009] [Revised: 11/19/2009] [Accepted: 11/25/2009] [Indexed: 11/16/2022]
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Mutze G, Sinclair R, Peacock D, Kovaliski J, Capucci L. Does a benign calicivirus reduce the effectiveness of rabbit haemorrhagic disease virus (RHDV) in Australia? Experimental evidence from field releases of RHDV on bait. WILDLIFE RESEARCH 2010. [DOI: 10.1071/wr09162] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Context. European rabbits are serious environmental and agricultural pests throughout their range in Australia. Rabbit haemorrhagic disease virus (RHDV) greatly reduced rabbit numbers in arid central Australia but had less impact in cooler, higher-rainfall areas. RHDV-like benign caliciviruses (bCVs) have been implicated in limiting the impact of RHDV in the higher-rainfall regions of Australia and also in Europe.
Aims. Experimental releases of RHDV on bait were tested as a means of initiating disease outbreaks. Serological evidence of antibodies to bCVs was examined to determine whether they reduce mortality rates and/or spread of the released RHDV, and how that might influence the effectiveness of future RHDV releases for rabbit management.
Methods. Four experimental releases were conducted in high-rainfall and coastal regions of southern Australia. Virus activity was implied from recapture rates and serological changes in marked rabbits, and genetic sequencing of virus recovered from dead rabbits. Changes in rabbit abundance were estimated from spotlight transect counts.
Key results. Release of RHDV on bait produced disease outbreaks that challenged almost all animals within the general release area and spread up to 4 km beyond the release sites. Recapture rates were high in marked rabbits that possessed antibodies from previous exposure to RHDV and extremely low amongst rabbits that lacked any detectable antibodies. Rabbits carrying antibodies classified as being due to previous infection with bCVs had recapture rates that were dependent on circulating antibody titre and were ~55% of recapture rates in rabbits with clear antibodies to RHDV.
Conclusions. This is the first quantified evidence that antibodies produced against bCVs provide significant protection against RHD outbreaks in field populations of rabbits.
Implications. bCVs can greatly reduce the impact of RHDV on wild-rabbit populations in Australia and presumably elsewhere. RHDV can be effectively released on bait although further releases are likely to be of minor or inconsistent benefit for controlling rabbit numbers where bCVs are common.
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