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Smertina E, Keller LM, Huang N, Flores-Benner G, Correa-Cuadros JP, Duclos M, Jaksic FM, Briceño C, Ramirez VN, Díaz-Gacitúa M, Carrasco-Fernández S, Smith IL, Strive T, Jenckel M. First Detection of Benign Rabbit Caliciviruses in Chile. Viruses 2024; 16:439. [PMID: 38543804 PMCID: PMC10974056 DOI: 10.3390/v16030439] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2024] [Revised: 02/29/2024] [Accepted: 03/06/2024] [Indexed: 05/23/2024] Open
Abstract
Pathogenic lagoviruses (Rabbit hemorrhagic disease virus, RHDV) are widely spread across the world and are used in Australia and New Zealand to control populations of feral European rabbits. The spread of the non-pathogenic lagoviruses, e.g., rabbit calicivirus (RCV), is less well studied as the infection results in no clinical signs. Nonetheless, RCV has important implications for the spread of RHDV and rabbit biocontrol as it can provide varying levels of cross-protection against fatal infection with pathogenic lagoviruses. In Chile, where European rabbits are also an introduced species, myxoma virus was used for localised biocontrol of rabbits in the 1950s. To date, there have been no studies investigating the presence of lagoviruses in the Chilean feral rabbit population. In this study, liver and duodenum rabbit samples from central Chile were tested for the presence of lagoviruses and positive samples were subject to whole RNA sequencing and subsequent data analysis. Phylogenetic analysis revealed a novel RCV variant in duodenal samples that likely originated from European RCVs. Sequencing analysis also detected the presence of a rabbit astrovirus in one of the lagovirus-positive samples.
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Affiliation(s)
- Elena Smertina
- Commonwealth Scientific and Industrial Research Organisation, Health and Biosecurity, Black Mountain, Canberra, ACT 2601, Australia; (E.S.); (L.M.K.); (N.H.); (I.L.S.); (T.S.)
| | - Luca M. Keller
- Commonwealth Scientific and Industrial Research Organisation, Health and Biosecurity, Black Mountain, Canberra, ACT 2601, Australia; (E.S.); (L.M.K.); (N.H.); (I.L.S.); (T.S.)
| | - Nina Huang
- Commonwealth Scientific and Industrial Research Organisation, Health and Biosecurity, Black Mountain, Canberra, ACT 2601, Australia; (E.S.); (L.M.K.); (N.H.); (I.L.S.); (T.S.)
| | - Gabriela Flores-Benner
- Departamento de Ecología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago 8331150, Chile; (G.F.-B.); (J.P.C.-C.); (F.M.J.)
- Center of Applied Ecology and Sustainability (CAPES), Santiago 8331150, Chile; (M.D.); (S.C.-F.)
| | - Jennifer Paola Correa-Cuadros
- Departamento de Ecología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago 8331150, Chile; (G.F.-B.); (J.P.C.-C.); (F.M.J.)
- Center of Applied Ecology and Sustainability (CAPES), Santiago 8331150, Chile; (M.D.); (S.C.-F.)
| | - Melanie Duclos
- Center of Applied Ecology and Sustainability (CAPES), Santiago 8331150, Chile; (M.D.); (S.C.-F.)
- Centro de Investigación para la Sustentabilidad, Universidad Andrés Bello (CIS-UNAB), Santiago 8370251, Chile
| | - Fabian M. Jaksic
- Departamento de Ecología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago 8331150, Chile; (G.F.-B.); (J.P.C.-C.); (F.M.J.)
- Center of Applied Ecology and Sustainability (CAPES), Santiago 8331150, Chile; (M.D.); (S.C.-F.)
| | - Cristóbal Briceño
- Departamento de Medicina Preventiva Animal, Facultad de Ciencias Veterinarias y Pecuarias, Universidad de Chile, Santiago 8330111, Chile; (C.B.); (V.N.R.)
| | - Victor Neira Ramirez
- Departamento de Medicina Preventiva Animal, Facultad de Ciencias Veterinarias y Pecuarias, Universidad de Chile, Santiago 8330111, Chile; (C.B.); (V.N.R.)
| | | | - Sebastián Carrasco-Fernández
- Center of Applied Ecology and Sustainability (CAPES), Santiago 8331150, Chile; (M.D.); (S.C.-F.)
- Magíster en Recursos Naturales, Facultad de Ciencias de la Vida, Universidad Andrés Bello, República 440, Santiago 8370251, Chile
| | - Ina L. Smith
- Commonwealth Scientific and Industrial Research Organisation, Health and Biosecurity, Black Mountain, Canberra, ACT 2601, Australia; (E.S.); (L.M.K.); (N.H.); (I.L.S.); (T.S.)
| | - Tanja Strive
- Commonwealth Scientific and Industrial Research Organisation, Health and Biosecurity, Black Mountain, Canberra, ACT 2601, Australia; (E.S.); (L.M.K.); (N.H.); (I.L.S.); (T.S.)
| | - Maria Jenckel
- Commonwealth Scientific and Industrial Research Organisation, Health and Biosecurity, Black Mountain, Canberra, ACT 2601, Australia; (E.S.); (L.M.K.); (N.H.); (I.L.S.); (T.S.)
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2
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Dorji T, Jayasingha Ellakkala Appuhamilage RMJ, Bird PL, Huang N, O’Connor TW, Patel KK, Strive T, Taggart PL. Optimising the Delivery of RHDV to Rabbits for Biocontrol: An Experimental Evaluation of Two Novel Methods of Virus Delivery. Viruses 2023; 15:1814. [PMID: 37766220 PMCID: PMC10536075 DOI: 10.3390/v15091814] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2023] [Revised: 08/21/2023] [Accepted: 08/24/2023] [Indexed: 09/29/2023] Open
Abstract
Rabbit haemorrhagic disease virus (RHDV) is established as a landscape-scale biocontrol that assists the management of invasive European rabbits and their impacts in both Australia and New Zealand. In addition to this, it is also available to land managers to augment rabbit control efforts at a local scale. However, current methods of deploying RHDV to rabbits that rely on the consumption of virus-treated baits can be problematic as rabbits are reluctant to consume bait when there is abundant, green, protein-rich feed available. We ran a suite of interrupted time-series experiments to compare the duration of infectivity of two conventional (carrot and oat baits) and two novel (meat bait and soil burrow spray) methods of deploying RHDV to rabbits. All methods effectively killed exposed rabbits. Soil burrow spray and carrot baits resulted in infection and mortality out to 5 days post their deployment in the field, and meat baits caused infection out to 10 days post their deployment. In contrast, oat baits continued to infect and kill exposed rabbits out to 20 days post deployment. Molecular assays demonstrated high viral loads in deployed baits beyond the duration for which they were infectious or lethal to rabbits. Based on our results, we suggest that the drying of meat baits may create a barrier to effective transmission of RHDV by adult flies within 10 days. We therefore hypothesise that fly larvae production and development on infected tissues is critical to prolonged viral transmission from meat baits, and similarly from carcasses of RHDV mortalities, via mechanical fly vectors. Our study demonstrates that meat baits and soil spray could provide additional virus deployment options that remove the need for rabbits to consume baits at times when they are reluctant to do so.
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Affiliation(s)
- Tshewang Dorji
- Biosecurity, Department of Primary Industries and Regions (PIRSA), Urrbrae, SA 5064, Australia; (T.D.); (R.M.J.J.E.A.); (K.K.P.)
- School of Food, Agriculture and Wine, The University of Adelaide, Urrbrae, SA 5064, Australia
| | | | - Peter L. Bird
- Waite Conservation Reserve, University of Adelaide, Urrbrae, SA 5064, Australia;
| | - Nina Huang
- Health & Biosecurity, Commonwealth Scientific and Industrial Research Organisation, Acton, ACT 2601, Australia; (N.H.); (T.S.)
| | - Tiffany W. O’Connor
- Virology Laboratory, Elizabeth Macarthur Agricultural Institute, Department of Primary Industries NSW, Menangle, NSW 2568, Australia
| | - Kandarp K. Patel
- Biosecurity, Department of Primary Industries and Regions (PIRSA), Urrbrae, SA 5064, Australia; (T.D.); (R.M.J.J.E.A.); (K.K.P.)
- School of Animal and Veterinary Sciences, The University of Adelaide, Roseworthy, SA 5371, Australia
| | - Tanja Strive
- Health & Biosecurity, Commonwealth Scientific and Industrial Research Organisation, Acton, ACT 2601, Australia; (N.H.); (T.S.)
| | - Patrick L. Taggart
- School of Animal and Veterinary Sciences, The University of Adelaide, Roseworthy, SA 5371, Australia
- Vertebrate Pest Research Unit, Department of Primary Industries NSW, Queanbeyan, NSW 2620, Australia
- School of Biological, Earth and Environmental Sciences, University of New South Wales, Sydney, NSW 2000, Australia
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3
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Immunological Cross-Protection between Different Rabbit Hemorrhagic Disease Viruses—Implications for Rabbit Biocontrol and Vaccine Development. Vaccines (Basel) 2022; 10:vaccines10050666. [PMID: 35632422 PMCID: PMC9143016 DOI: 10.3390/vaccines10050666] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2022] [Revised: 04/19/2022] [Accepted: 04/20/2022] [Indexed: 11/17/2022] Open
Abstract
The use of rabbit hemorrhagic disease virus (RHDV) as a biocontrol agent to control feral rabbit populations in Australia, in combination with circulating endemic strains, provides a unique environment to observe the interactions between different lagoviruses competing for the same host. Following the arrival of RHDV2 (GI.2) in Australia, it became necessary to investigate the potential for immunological cross-protection between different variants, and the implications of this for biocontrol programs and vaccine development. Laboratory rabbits of various immune status—(1) rabbits with no detectable immunity against RHDV; (2) rabbits with experimentally acquired immunity after laboratory challenge; (3) rabbits immunised with a GI.2-specific or a multivalent RHDV inactivated virus prototype vaccine; or (4) rabbits with naturally acquired immunity—were challenged with one of three different RHDV variants (GI.1c, GI.1a or GI.2). The degree of cross-protection observed in immune rabbits was associated with the variant used for challenge, infectious dose of the virus and age, or time since acquisition of the immunity, at challenge. The immune status of feral rabbit populations should be determined prior to intentional RHDV release because of the high survival proportions in rabbits with pre-existing immunity. In addition, to protect domestic rabbits in Australia, a multivalent RHDV vaccine should be considered because of the limited cross-protection observed in rabbits given monovalent vaccines.
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Hall RN, King T, O’Connor TW, Read AJ, Vrankovic S, Piper M, Strive T. Passive Immunisation against RHDV2 Induces Protection against Disease but Not Infection. Vaccines (Basel) 2021; 9:vaccines9101197. [PMID: 34696305 PMCID: PMC8537872 DOI: 10.3390/vaccines9101197] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2021] [Revised: 10/15/2021] [Accepted: 10/15/2021] [Indexed: 11/16/2022] Open
Abstract
Rabbit haemorrhagic disease virus 2 (RHDV2) is a lagovirus in the family Caliciviridae. The closely related Rabbit haemorrhagic disease virus (RHDV, termed RHDV1 throughout this manuscript for clarity) has been used extensively as a biocontrol agent in Australia since the mid-1990s to manage wild rabbit populations, a major economic and environmental pest species. Releasing RHDV1 into populations with a high proportion of rabbits less than 8–10 weeks of age leads to non-lethal infection in many of these young animals, with subsequent seroconversion and long-term immunity against reinfection. In contrast, RHDV2 causes lethal disease even in young rabbits, potentially offering substantial benefits for rabbit management programs over RHDV1. However, it is not clear how acquired resistance from maternal antibodies may influence immunity after RHDV2 infection. In this study, we assessed serological responses after RHDV2 challenge in young rabbits of three different ages (5-, 7-, or 9-weeks-old) that were passively immunised with either high- (titre of 2560 by RHDV IgG ELISA; 2.41 mg/mL total protein) or low- (titre of 160–640 by RHDV IgG ELISA; 1.41 mg/mL total protein) dose RHDV2 IgG to simulate maternal antibodies. All rabbits treated with a high dose and 75% of those treated with a low dose of RHDV2 IgG survived virus challenge. Surviving animals developed robust lagovirus-specific IgA, IgM, and IgG responses within 10 days post infection. These findings demonstrate that the protection against RHDV2 conferred by passive immunisation is not sterilising. Correspondingly, this suggests that the presence of maternal antibodies in wild rabbit populations may impede the effectiveness of RHDV2 as a biocontrol.
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Affiliation(s)
- Robyn N. Hall
- Health & Biosecurity, Commonwealth Scientific and Industrial Research Organisation, Acton, ACT 2601, Australia; (T.K.); (T.S.)
- Centre for Invasive Species Solutions, Bruce, ACT 2617, Australia
- Correspondence: ; Tel.: +61-2-6246-4245
| | - Tegan King
- Health & Biosecurity, Commonwealth Scientific and Industrial Research Organisation, Acton, ACT 2601, Australia; (T.K.); (T.S.)
| | - Tiffany W. O’Connor
- Elizabeth Macarthur Agricultural Institute, NSW Department of Primary Industries, Menangle, NSW 2568, Australia (A.J.R.); (S.V.)
| | - Andrew J. Read
- Elizabeth Macarthur Agricultural Institute, NSW Department of Primary Industries, Menangle, NSW 2568, Australia (A.J.R.); (S.V.)
| | - Sylvia Vrankovic
- Elizabeth Macarthur Agricultural Institute, NSW Department of Primary Industries, Menangle, NSW 2568, Australia (A.J.R.); (S.V.)
| | - Melissa Piper
- Agriculture & Food, Commonwealth Scientific and Industrial Research Organisation, Acton, ACT 2601, Australia;
| | - Tanja Strive
- Health & Biosecurity, Commonwealth Scientific and Industrial Research Organisation, Acton, ACT 2601, Australia; (T.K.); (T.S.)
- Centre for Invasive Species Solutions, Bruce, ACT 2617, Australia
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Lim K, Tan A, Ho K, Sng W, Lim HP, Chan C, Toh X, Ong J, Chang SF, Fernandez CJ. Resolution of rabbit haemorrhagic disease virus 2 (RHDV2; Lagovirus europeus GI.2) outbreak in Singapore. Transbound Emerg Dis 2021; 69:3077-3083. [PMID: 34480780 DOI: 10.1111/tbed.14312] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2021] [Revised: 08/30/2021] [Accepted: 09/02/2021] [Indexed: 11/29/2022]
Abstract
Rabbit haemorrhagic disease (RHD) is a highly contagious viral disease affecting lagomorphs. The first documented cases of RHD in Singapore occurred in adult pet European rabbits in September 2020. Singapore subsequently declared the outbreak resolved in December 2020. Epidemiological investigations ruled out introductions via importation of infected rabbits and contaminated feed. The source could not be definitively determined. However, the findings suggested that the incident involved both inter- and intra-household transmission and veterinary clinic-household transmission. This incident demonstrated the importance of sustained application of biosecurity measures, epidemiological investigations including active case finding, control measures such as expedient vaccine dissemination and risk communications. It showed that even without a wild lagomorph population, an urbanized city-state like Singapore could still encounter emerging diseases such as RHD. Given its social impact on rabbit owners, the National Parks Board, Singapore and private veterinarians worked together to communicate with rabbit owners in order to urge them to adopt biosecurity measures and to address their concerns.
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Affiliation(s)
- Kelvin Lim
- Professional and Scientific Services, Animal and Veterinary Service, National Parks Board (NParks), Botanic Gardens, Singapore, Singapore
| | - Alwyn Tan
- Professional and Scientific Services, Animal and Veterinary Service, National Parks Board (NParks), Botanic Gardens, Singapore, Singapore
| | - Kelvin Ho
- Professional and Scientific Services, Animal and Veterinary Service, National Parks Board (NParks), Botanic Gardens, Singapore, Singapore
| | - Wendy Sng
- Professional and Scientific Services, Animal and Veterinary Service, National Parks Board (NParks), Botanic Gardens, Singapore, Singapore
| | - Hwee Ping Lim
- Professional and Scientific Services, Animal and Veterinary Service, National Parks Board (NParks), Botanic Gardens, Singapore, Singapore
| | - Cathy Chan
- The Animal Doctors Pte Ltd (Singapore), Singapore, Singapore
| | - Xinyu Toh
- Professional and Scientific Services, Animal and Veterinary Service, National Parks Board (NParks), Botanic Gardens, Singapore, Singapore
| | - Jasmine Ong
- Professional and Scientific Services, Animal and Veterinary Service, National Parks Board (NParks), Botanic Gardens, Singapore, Singapore
| | - Siow Foong Chang
- Professional and Scientific Services, Animal and Veterinary Service, National Parks Board (NParks), Botanic Gardens, Singapore, Singapore
| | - Charlene Judith Fernandez
- Professional and Scientific Services, Animal and Veterinary Service, National Parks Board (NParks), Botanic Gardens, Singapore, Singapore
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Lim ZJK, Xie S. Application of Epidemiology and Principles of Herd/Flock Health for the Exotic Animal Veterinarian. Vet Clin North Am Exot Anim Pract 2021; 24:495-507. [PMID: 34366006 DOI: 10.1016/j.cvex.2021.04.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
Against a backdrop of climate change and epidemics, the exotic animal veterinarian is well positioned to detect emerging and exotic disease threats, prevent and control zoonotic diseases, and identify antimicrobial resistance. Within the traditional context of animal and public health, epidemiology has had a focus on veterinary preventive health and in disease investigation and control particularly in food animal and safety application. The understanding of preventive health management and veterinary epidemiology expands the repertoire of the clinical veterinarian to advise and implement and evaluate group animal health programs and biosecurity measures as well as conduct disease investigations.
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Affiliation(s)
| | - Shangzhe Xie
- Conservation, Research and Veterinary Department, Wildlife Reserves Singapore, 80 Mandai Lake Road, Singapore 729826
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7
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Abrantes J, Lopes AM. A Review on the Methods Used for the Detection and Diagnosis of Rabbit Hemorrhagic Disease Virus (RHDV). Microorganisms 2021; 9:972. [PMID: 33946292 PMCID: PMC8146303 DOI: 10.3390/microorganisms9050972] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2021] [Revised: 04/26/2021] [Accepted: 04/27/2021] [Indexed: 01/10/2023] Open
Abstract
Since the early 1980s, the European rabbit (Oryctolagus cuniculus) has been threatened by the rabbit hemorrhagic disease (RHD). The disease is caused by a lagovirus of the family Caliciviridae, the rabbit hemorrhagic disease virus (RHDV). The need for detection, identification and further characterization of RHDV led to the development of several diagnostic tests. Owing to the lack of an appropriate cell culture system for in vitro propagation of the virus, much of the methods involved in these tests contributed to our current knowledge on RHD and RHDV and to the development of vaccines to contain the disease. Here, we provide a comprehensive review of the RHDV diagnostic tests used since the first RHD outbreak and that include molecular, histological and serological techniques, ranging from simpler tests initially used, such as the hemagglutination test, to the more recent and sophisticated high-throughput sequencing, along with an overview of their potential and their limitations.
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Affiliation(s)
- Joana Abrantes
- CIBIO/InBio-UP, Centro de Investigação em Biodiversidade e Recursos Genéticos, Universidade do Porto, 4485-661 Vairão, Portugal;
- Departamento de Biologia, Faculdade de Ciências da Universidade do Porto, 4169-007 Porto, Portugal
| | - Ana M. Lopes
- CIBIO/InBio-UP, Centro de Investigação em Biodiversidade e Recursos Genéticos, Universidade do Porto, 4485-661 Vairão, Portugal;
- Instituto de Ciências Biomédicas Abel Salazar (ICBAS)/Unidade Multidisciplinar de Investigação Biomédica (UMIB), Universidade do Porto, 4050-313 Porto, Portugal
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8
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Taggart PL, Hall RN, Cox TE, Kovaliski J, McLeod SR, Strive T. Changes in virus transmission dynamics following the emergence of RHDV2 shed light on its competitive advantage over previously circulating variants. Transbound Emerg Dis 2021; 69:1118-1130. [PMID: 33724677 DOI: 10.1111/tbed.14071] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2020] [Revised: 03/10/2021] [Accepted: 03/12/2021] [Indexed: 01/17/2023]
Abstract
Rabbit haemorrhagic disease virus (RHDV) is highly pathogenic to European rabbits. Until recently, only one serotype of RHDV was known, GI.1/RHDV. RHDV2/GI.2 is a novel virus that has rapidly spread and become the dominant pathogenic calicivirus in wild rabbits worldwide. It is speculated that RHDV2 has three competitive advantages over RHDV: (a) the ability to partially overcome immunity to other variants; (b) the ability to clinically infect young rabbits; and (c) a wider host range. These differences would be expected to influence virus transmission dynamics. We used markers of recent infection (IgM/IgA antibodies) to investigate virus transmission dynamics pre and post the arrival of RHDV2. Our data set contained over 3,900 rabbits sampled across a 7-year period at 12 Australian sites. Following the arrival of RHDV2, seasonal peaks in IgM and IgA seropositivity shifted forward one season, from winter to autumn and spring to winter, respectively. Contrary to predictions, we found only weak effects of rabbit age, seropositivity to non-pathogenic calicivirus RCV-A1 and population abundance on IgM/IgA seropositivity. Our results demonstrate that RHDV2 enters rabbit populations shortly after the commencement of annual breeding cycles. Upon entering, the population RHDV2 undergoes extensive replication in young rabbits, causing clinical disease, high virus shedding, mortality and the creation of virus-laden carcasses. This results in high virus contamination in the environment, furthering the transmission of RHDV2 and initiating outbreaks, whilst simultaneously removing the susceptible cohort required for the effective transmission of RHDV. Although RHDV may enter the population at the same time point, it is sub-clinical in young rabbits, causing minimal virus shedding and low environmental contamination. Our results demonstrate a major shift in epidemiological patterns in virus transmission, providing the first evidence that RHDV2's ability to clinically infect young rabbits is a key competitive advantage in the field.
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Affiliation(s)
- Patrick L Taggart
- Vertebrate Pest Research Unit, Department of Primary Industries NSW, Orange, NSW, Australia.,Centre for Invasive Species Solutions, Bruce, ACT, Australia.,School of Animal and Veterinary Sciences, The University of Adelaide, Roseworthy, SA, Australia
| | - Robyn N Hall
- Centre for Invasive Species Solutions, Bruce, ACT, Australia.,CSIRO Health and Biosecurity, Acton, ACT, Australia
| | - Tarnya E Cox
- Vertebrate Pest Research Unit, Department of Primary Industries NSW, Orange, NSW, Australia
| | - John Kovaliski
- Biosecurity SA, Adelaide, SA, Australia.,Invasive Animals Cooperative Research Centre, University of Canberra, Bruce, ACT, Australia
| | - Steven R McLeod
- Vertebrate Pest Research Unit, Department of Primary Industries NSW, Orange, NSW, Australia
| | - Tanja Strive
- Centre for Invasive Species Solutions, Bruce, ACT, Australia.,CSIRO Health and Biosecurity, Acton, ACT, Australia
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9
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Strive T, Piper M, Huang N, Mourant R, Kovaliski J, Capucci L, Cox TE, Smith I. Retrospective serological analysis reveals presence of the emerging lagovirus RHDV2 in Australia in wild rabbits at least five months prior to its first detection. Transbound Emerg Dis 2019; 67:822-833. [PMID: 31665828 DOI: 10.1111/tbed.13403] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2019] [Revised: 10/23/2019] [Accepted: 10/24/2019] [Indexed: 12/16/2022]
Abstract
The lagovirus rabbit haemorrhagic disease virus (RHDV) has been circulating in Australia since the mid-1990s when it was released to control overabundant rabbit populations. In recent years, the viral diversity of different RHDVs in Australia has increased, and currently four different types of RHDV are known to be circulating. To allow for ongoing epidemiological studies and impact assessments of these viruses on Australian wild rabbit populations, it is essential that serological tools are updated. To this end, reference sera were produced against all four virulent RHDVs (RHDV, RHDV2 and two different strains of RHDVa) known to be present in Australia and tested in a series of available immunological assays originally developed for the prototype RHDV, to assess patterns of cross-reactivity and the usefulness of these assays to detect lagovirus antibodies, either in a generic or specific manner. Enzyme-linked immunosorbent assays (ELISAs) developed to detect antibody isotypes IgM, IgA and IgG were sufficiently cross-reactive to detect antibodies raised against all four virulent lagoviruses. For the more specific detection of antibodies to the antigenically more different RHDV2, a competition ELISA was adapted using RHDV2-specific monoclonal antibodies in combination with Australian viral antigen. Archival serum banks from a long-term rabbit monitoring site where rabbits were sampled quarterly over a period of 6 years were re-screened using this assay and revealed serological evidence for the arrival of RHDV2 in this population at least 5 months prior to its initial detection in Australia in a dead rabbit in May 2015. The serological methods and reference reagents described here will provide valuable tools to study presence, prevalence and impact of RHDV2 on Australian rabbit populations; however, the discrimination of different antigenic variants of RHDVs as well as mixed infections at the serological level remains challenging.
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Affiliation(s)
- Tanja Strive
- Commonwealth Scientific and Industrial Research Organisation, Canberra, Australia.,Centre for Invasive Species Solutions, University of Canberra, Bruce, Australia
| | - Melissa Piper
- Commonwealth Scientific and Industrial Research Organisation, Canberra, Australia
| | - Nina Huang
- Commonwealth Scientific and Industrial Research Organisation, Canberra, Australia.,Centre for Invasive Species Solutions, University of Canberra, Bruce, Australia
| | - Roslyn Mourant
- Commonwealth Scientific and Industrial Research Organisation, Canberra, Australia
| | - John Kovaliski
- Department of Primary Industries and Regions, Biosecurity SA, Adelaide, Australia
| | - Lorenzo Capucci
- Istituto Zooprofilattico Sperimentale della Lombardia e dell'Emilia Romagna 'Bruno Ubertini' (IZSLER), OIE Reference Laboratory for Rabbit Haemorrhagic Disease, Brescia, Italy
| | - Tarnya E Cox
- Centre for Invasive Species Solutions, University of Canberra, Bruce, Australia.,Vertebrate Pest Research Unit, New South Wales Department of Primary Industries, Orange, Australia
| | - Ina Smith
- Commonwealth Scientific and Industrial Research Organisation, Canberra, Australia
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10
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High-throughput Luminex xMAP assay for simultaneous detection of antibodies against rabbit hemorrhagic disease virus, Sendai virus and rabbit rotavirus. Arch Virol 2019; 164:1639-1646. [PMID: 30982935 PMCID: PMC7087182 DOI: 10.1007/s00705-019-04226-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2018] [Accepted: 03/01/2019] [Indexed: 11/17/2022]
Abstract
Rabbits are widely used as models in biological research, and the pathogen status of rabbits used in studies can directly affect the results of experiments. Serological surveillance is the common monitoring method used in laboratory animals. A rapid, sensitive, and cost-effective high-throughput Luminex xMAP assay could be an attractive alternative to labor-intensive enzyme-linked immunosorbent assay (ELISA) methods. In this study, recombinant proteins from rabbit hemorrhagic disease virus and rabbit rotavirus and whole viral lysates of Sendai virus were used as coating antigens in an xMAP assay for the simultaneous detection of antibodies against these pathogens. The xMAP assay showed high specificity, with no cross-reaction with other pathogens. The coefficient of variation for intra-assay and inter-assay comparisons was less than 3% and 4%, respectively, indicating good repeatability and stability of the assay. The xMAP assay exhibited similar limits of detection for rabbit hemorrhagic virus and Sendai virus and was less sensitive for the detection of rabbit rotavirus when compared with commercial ELISA kits. A total of 52 clinical samples were tested simultaneously using both the xMAP assay and ELISA kits. The results obtained using these two methods were 100% coincident. In summary, the novel xMAP assay offers an alternative choice for rapid and sensitive high-throughput detection of antibodies in rabbit serum and can be used as a daily monitoring tool for laboratory animals.
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11
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Mahar JE, Read AJ, Gu X, Urakova N, Mourant R, Piper M, Haboury S, Holmes EC, Strive T, Hall RN. Detection and Circulation of a Novel Rabbit Hemorrhagic Disease Virus in Australia. Emerg Infect Dis 2018; 24:22-31. [PMID: 29260677 PMCID: PMC5749467 DOI: 10.3201/eid2401.170412] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
The highly virulent rabbit hemorrhagic disease virus (RHDV) has been widely used in Australia and New Zealand since the mid-1990s to control wild rabbits, an invasive vertebrate pest in these countries. In January 2014, an exotic RHDV was detected in Australia, and 8 additional outbreaks were reported in both domestic and wild rabbits in the 15 months following its detection. Full-length genomic analysis revealed that this virus is a recombinant containing an RHDVa capsid gene and nonstructural genes most closely related to nonpathogenic rabbit caliciviruses. Nationwide monitoring efforts need to be expanded to assess if the increasing number of different RHDV variants circulating in the Australian environment will affect biological control of rabbits. At the same time, updated vaccines and vaccination protocols are urgently needed to protect pet and farmed rabbits from these novel rabbit caliciviruses.
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12
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Neimanis A, Larsson Pettersson U, Huang N, Gavier-Widén D, Strive T. Elucidation of the pathology and tissue distribution of Lagovirus europaeus GI.2/RHDV2 (rabbit haemorrhagic disease virus 2) in young and adult rabbits (Oryctolagus cuniculus). Vet Res 2018; 49:46. [PMID: 29866169 PMCID: PMC5987473 DOI: 10.1186/s13567-018-0540-z] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2018] [Accepted: 05/03/2018] [Indexed: 01/28/2023] Open
Abstract
Lagovirus europaeus GI.2, also known as RHDV2 or RHDVb, is an emerging virus that causes rabbit haemorrhagic disease (RHD) in European rabbits (Oryctolagus cuniculus). In contrast to L. europaeus GI.1 (or RHDV/RHDVa) viruses that are only pathogenic for adults, GI.2 causes clinical disease in both adults and kittens. However, detailed descriptions of the pathology of this virus that may provide insight into its pathogenicity and emergence are lacking. Using an Australian GI.2 field strain isolated in 2015, we provide the first detailed description of pathology, viral antigen distribution and tissue load of GI.2 in adult and 5-week old New Zealand white rabbits using histology, immunohistochemistry and RT-qPCR. Liver was the target organ, but in contrast to GI.1 viruses, lesions and inflammatory responses did not differ between adults and kittens. Lymphocytic inflammation, proposed to be protective in kittens infected with GI.1, was notably absent. We also present the first descriptions of bone marrow changes in RHD, including decreased myeloid-to-erythroid ratio. Consistent with other pathogenic lagoviruses, intracellular viral antigen was demonstrated in hepatocytes and cells of the mononuclear phagocytic system. In terminal stages of disease, viral loads were highest in liver, serum and spleen. Despite the small sample size, our data suggest that unlike early European GI.2 strains, the pathogenicity of the Australian GI.2 virus is similar to GI.1 viruses. Additionally, GI.2 was fatal for all (n = 5) inoculated kittens in this study. This may significantly alter RHD epidemiology in the field, and may impact biocontrol programs for invasive rabbits in Australia where GI.1 viruses are intentionally released.
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Affiliation(s)
- Aleksija Neimanis
- Department of Pathology and Wildlife Diseases, National Veterinary Institute (SVA), 751 89, Uppsala, Sweden. .,Department of Biomedical Sciences and Veterinary Public Health, Swedish University of Agricultural Sciences (SLU), 750 07, Uppsala, Sweden.
| | - Ulrika Larsson Pettersson
- Department of Pathology and Wildlife Diseases, National Veterinary Institute (SVA), 751 89, Uppsala, Sweden
| | - Nina Huang
- Commonwealth Scientific and Industrial Research Organisation (CSIRO), Health & Biosecurity, Black Mountain Laboratories, Canberra, Australia
| | - Dolores Gavier-Widén
- Department of Pathology and Wildlife Diseases, National Veterinary Institute (SVA), 751 89, Uppsala, Sweden.,Department of Biomedical Sciences and Veterinary Public Health, Swedish University of Agricultural Sciences (SLU), 750 07, Uppsala, Sweden
| | - Tanja Strive
- Commonwealth Scientific and Industrial Research Organisation (CSIRO), Health & Biosecurity, Black Mountain Laboratories, Canberra, Australia
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13
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Wu M, Zhu Y, Cong F, Rao D, Yuan W, Wang J, Huang B, Lian Y, Zhang Y, Huang R, Guo P. Rapid detection of three rabbit pathogens by use of the Luminex x-TAG assay. BMC Vet Res 2018; 14:127. [PMID: 29625588 PMCID: PMC5889542 DOI: 10.1186/s12917-018-1438-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2017] [Accepted: 03/19/2018] [Indexed: 01/18/2023] Open
Abstract
Background Domestic rabbits especially New Zealand white rabbits play an important role in biological research. The disease surveillance and quality control are essential to guarantee the results of animal experiments performed on rabbits. Rabbit hemorrhagic disease virus, rabbit rotavirus and Sendai virus are the important pathogens that needed to be eliminated. Rapid and sensitive method focus on these three viruses should be established for routine monitoring. The Luminex x-TAG assay based on multiplex PCR and fluorescent microsphere is a fast developing technology applied in high throughput detection. Specific primers modified with oligonucleotide sequence/biotin were used to amplify target fragments. The conjugation between oligonucleotide sequence of the PCR products and the MagPlex-TAG microspheres was specific without any cross-reaction, and the hybridization products could be analyzed using the Luminex 200 analyzer instrument. Recombinant plasmids were constructed to estimate the detection limit of the viruses. Furthermore, 40 clinical samples were used to evaluate the efficiency of this multiplex PCR based Luminex x-TAG assay. Results According to the results, this new method showed high specificity and good stability. Assessed by the recombinant plasmids, the detection limit of three viruses was 100copies/μl. Among 40 clinical specimens, 18 specimens were found positive, which was completely concordant with the conventional PCR method. Conclusions The new developed Luminex x-TAG assay is an accurate, high throughput method for rapid detection of three important viruses of rabbits.
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Affiliation(s)
- Miaoli Wu
- Guangdong Provincial Key Laboratory of Laboratory Animals, Guangzhou, 510633, China.,Guangdong Laboratory Animal Monitoring Institute, Guangzhou, China
| | - Yujun Zhu
- Guangdong Laboratory Animal Monitoring Institute, Guangzhou, China
| | - Feng Cong
- Guangdong Provincial Key Laboratory of Laboratory Animals, Guangzhou, 510633, China
| | - Dan Rao
- Guangdong Laboratory Animal Monitoring Institute, Guangzhou, China
| | - Wen Yuan
- Guangdong Provincial Key Laboratory of Laboratory Animals, Guangzhou, 510633, China
| | - Jing Wang
- Guangdong Provincial Key Laboratory of Laboratory Animals, Guangzhou, 510633, China
| | - Bihong Huang
- Guangdong Laboratory Animal Monitoring Institute, Guangzhou, China
| | - Yuexiao Lian
- Guangdong Laboratory Animal Monitoring Institute, Guangzhou, China
| | - Yu Zhang
- Guangdong Laboratory Animal Monitoring Institute, Guangzhou, China
| | - Ren Huang
- Guangdong laboratory animals monitoring institute, Guangzhou, 510633, China.
| | - Pengju Guo
- Guangdong key laboratory of laboratory Animals, Guangzhou, China.
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14
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Cooke BD, Duncan RP, McDonald I, Liu J, Capucci L, Mutze GJ, Strive T. Prior exposure to non-pathogenic calicivirus RCV-A1 reduces both infection rate and mortality from rabbit haemorrhagic disease in a population of wild rabbits in Australia. Transbound Emerg Dis 2017; 65:e470-e477. [DOI: 10.1111/tbed.12786] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2017] [Indexed: 11/30/2022]
Affiliation(s)
- B. D. Cooke
- Institute for Applied Ecology; University of Canberra; Canberra ACT Australia
| | - R. P. Duncan
- Institute for Applied Ecology; University of Canberra; Canberra ACT Australia
| | - I. McDonald
- CSIRO Health and Biosecurity; Canberra ACT Australia
- Invasive Animals Co-operative Research Centre; University of Canberra; Canberra ACT Australia
| | - J. Liu
- CSIRO Health and Biosecurity; Canberra ACT Australia
- Department of Agriculture and Water Resources; Canberra ACT Australia
| | - L. Capucci
- Istituto Zooprofilattico Sperimentale della Lombardia e dell'Emilia Romagna; Brescia Italy
| | - G. J. Mutze
- Biosecurity SA; PIRSA; Adelaide SA Australia
| | - T. Strive
- CSIRO Health and Biosecurity; Canberra ACT Australia
- Invasive Animals Co-operative Research Centre; University of Canberra; Canberra ACT Australia
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15
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Hall RN, Mahar JE, Read AJ, Mourant R, Piper M, Huang N, Strive T. A strain-specific multiplex RT-PCR for Australian rabbit haemorrhagic disease viruses uncovers a new recombinant virus variant in rabbits and hares. Transbound Emerg Dis 2017; 65:e444-e456. [PMID: 29226567 DOI: 10.1111/tbed.12779] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2017] [Indexed: 02/01/2023]
Abstract
Rabbit haemorrhagic disease virus (RHDV, or GI.1) is a calicivirus in the genus Lagovirus that has been widely utilized in Australia as a biological control agent for the management of overabundant wild European rabbit (Oryctolagus cuniculus) populations since 1996. Recently, two exotic incursions of pathogenic lagoviruses have been reported in Australia; GI.1a-Aus, previously called RHDVa-Aus, is a GI.1a virus detected in January 2014, and the novel lagovirus GI.2 (previously known as RHDV2). Furthermore, an additional GI.1a strain, GI.1a-K5 (also known as 08Q712), was released nationwide in March 2017 as a supplementary tool for wild rabbit management. To discriminate between these lagoviruses, a highly sensitive strain-specific multiplex RT-PCR assay was developed, which allows fast, cost-effective and sensitive detection of the four pathogenic lagoviruses currently known to be circulating in Australia. In addition, we developed a universal RT-qPCR assay to be used in conjunction with the multiplex assay that broadly detects all four viruses and facilitates quantification of viral RNA load in samples. These assays enable rapid detection, identification and quantification of pathogenic lagoviruses in the Australian context. Using these assays, a novel recombinant lagovirus was detected in rabbit tissue samples, which contained the non-structural genes of GI.1a-Aus and the structural genes of GI.2. This variant was also recovered from the liver of a European brown hare (Lepus europaeus). The impact of this novel recombinant on Australian wild lagomorph populations and its competitiveness in relation to circulating field strains, particularly GI.2, requires further studies.
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Affiliation(s)
- R N Hall
- CSIRO, Acton, ACT, Australia.,Invasive Animals Cooperative Research Centre, University of Canberra, Bruce, ACT, Australia
| | - J E Mahar
- CSIRO, Acton, ACT, Australia.,The University of Sydney, Sydney, NSW, Australia
| | - A J Read
- Elizabeth Macarthur Agricultural Institute, Menangle, NSW, Australia
| | | | - M Piper
- CSIRO, Acton, ACT, Australia
| | - N Huang
- CSIRO, Acton, ACT, Australia
| | - T Strive
- CSIRO, Acton, ACT, Australia.,Invasive Animals Cooperative Research Centre, University of Canberra, Bruce, ACT, Australia
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16
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Benign Rabbit Calicivirus in New Zealand. Appl Environ Microbiol 2017; 83:AEM.00090-17. [PMID: 28363968 DOI: 10.1128/aem.00090-17] [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] [Received: 01/10/2017] [Accepted: 03/22/2017] [Indexed: 11/20/2022] Open
Abstract
The Czech v351 strain of rabbit hemorrhagic disease virus (RHDV1) is used in Australia and New Zealand as a biological control agent for rabbits, which are important and damaging introduced vertebrate pests in these countries. However, nonpathogenic rabbit caliciviruses (RCVs) can provide partial immunological cross-protection against lethal RHDV infection and thus interfere with effective rabbit biocontrol. Antibodies that cross-reacted against RHDV antigens were found in wild rabbits before the release of RHDV1 in New Zealand in 1997, suggesting that nonpathogenic RCVs were already present in New Zealand. The aim of this study was to confirm the presence of nonpathogenic RCV in New Zealand and describe its geographical distribution. RCV and RHDV antibody assays were used to screen serum samples from 350 wild rabbits from 14 locations in New Zealand. The serological survey indicated that both RCV and RHDV are widespread in New Zealand wild rabbits, with antibodies detected in 10 out of 14 and 12 out of 14 populations, respectively. Two closely related RCV strains were identified in the duodenal tissue from a New Zealand wild rabbit (RCV Gore-425A and RCV Gore-425B). Both variants are most closely related to Australian RCV strains, but with 88% nucleotide identity, they are genetically distinct. Phylogenetic analysis revealed that the New Zealand RCV strains fall within the genetic diversity of the Australian RCV isolates, indicating a relatively recent movement of RCVs between Australia and New Zealand.IMPORTANCE Wild rabbits are important and damaging introduced vertebrate pests in Australia and New Zealand. Although RHDV1 is used as a biological control agent, some nonpathogenic RCVs can provide partial immunological cross-protection against lethal RHDV infection and thus interfere with its effectiveness for rabbit control. The presence of nonpathogenic RCVs in New Zealand wild rabbits has been long hypothesized, but earlier attempts to isolate a New Zealand RCV strain have been unsuccessful. Therefore, it is important to determine if such nonpathogenic viruses exist in New Zealand rabbits, especially considering the proposed introduction of new RHDV strains into New Zealand as biocontrols.
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17
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Hall RN, Capucci L, Matthaei M, Esposito S, Kerr PJ, Frese M, Strive T. An in vivo system for directed experimental evolution of rabbit haemorrhagic disease virus. PLoS One 2017; 12:e0173727. [PMID: 28288206 PMCID: PMC5348035 DOI: 10.1371/journal.pone.0173727] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2016] [Accepted: 02/24/2017] [Indexed: 11/25/2022] Open
Abstract
The calicivirus Rabbit haemorrhagic disease virus (RHDV) is widely used in Australia as a biocontrol agent to manage wild European rabbit (Oryctolagus cuniculus) populations. However, widespread herd immunity limits the effectiveness of the currently used strain, CAPM V-351. To overcome this, we developed an experimental platform for the selection and characterisation of novel RHDV strains. As RHDV does not replicate in cell culture, variant viruses were selected by serially passaging a highly virulent RHDV field isolate in immunologically naïve laboratory rabbits that were passively immunised 18–24 hours post-challenge with a neutralising monoclonal antibody. After seven passages, two amino acid substitutions in the P2 domain of the capsid protein became fixed within the virus population. Furthermore, a synonymous substitution within the coding sequence of the viral polymerase appeared and was also maintained in all subsequent passages. These findings demonstrate proof-of-concept that RHDV evolution can be experimentally manipulated to select for virus variants with altered phenotypes, in this case partial immune escape.
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Affiliation(s)
- Robyn N. Hall
- Health and Biosecurity, Commonwealth Scientific and Industrial Research Organisation, Canberra, ACT, Australia
- Invasive Animals Cooperative Research Centre, University of Canberra, Canberra, ACT, Australia
| | - Lorenzo Capucci
- IZSLER, Istituto Zooprofilattico Sperimentale della Lombardia e dell’Emilia Romagna “Bruno Ubertini”, Brescia, Italy
| | - Markus Matthaei
- Health and Biosecurity, Commonwealth Scientific and Industrial Research Organisation, Canberra, ACT, Australia
| | - Simona Esposito
- IZSLER, Istituto Zooprofilattico Sperimentale della Lombardia e dell’Emilia Romagna “Bruno Ubertini”, Brescia, Italy
| | - Peter J. Kerr
- Health and Biosecurity, Commonwealth Scientific and Industrial Research Organisation, Canberra, ACT, Australia
- School of Life and Environmental Sciences, University of Sydney, Sydney, NSW, Australia
| | - Michael Frese
- Health and Biosecurity, Commonwealth Scientific and Industrial Research Organisation, Canberra, ACT, Australia
- Invasive Animals Cooperative Research Centre, University of Canberra, Canberra, ACT, Australia
- Health Research Institute, University of Canberra, Canberra, ACT, Australia
- Institute for Applied Ecology, University of Canberra, Canberra, ACT, Australia
| | - Tanja Strive
- Health and Biosecurity, Commonwealth Scientific and Industrial Research Organisation, Canberra, ACT, Australia
- Invasive Animals Cooperative Research Centre, University of Canberra, Canberra, ACT, Australia
- Institute for Applied Ecology, University of Canberra, Canberra, ACT, Australia
- * E-mail:
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18
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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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19
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Cooke B, Springer K, Capucci L, Mutze G. Rabbit haemorrhagic disease: Macquarie Island rabbit eradication adds to knowledge on both pest control and epidemiology. WILDLIFE RESEARCH 2017. [DOI: 10.1071/wr16221] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Rabbit haemorrhagic disease virus (RHDV), introduced into in Australia and New Zealand as a biological-control agent for wild rabbits, is least efficacious in cool humid areas where a non-pathogenic calicivirus (RCV-A1) also circulates. Heavy rabbit mortality following release of RHDV on cold sub-Antarctic Macquarie Island, where RCV-A1 was apparently absent, not only complemented the planned rabbit eradication operations, especially by reducing secondary poisoning of sea-birds from aerial baiting, but also ruled out cool or humid climate as a major limiting factor of disease spread. In turn, this has advanced the idea that RCV-A1 antibodies inhibit RHDV spread as well as reducing disease severity and mortality.
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20
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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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21
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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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22
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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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