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Águeda-Pinto A, Lemos de Matos A, Abrantes M, Kraberger S, Risalde MA, Gortázar C, McFadden G, Varsani A, Esteves PJ. Genetic Characterization of a Recombinant Myxoma Virus in the Iberian Hare ( Lepus granatensis). Viruses 2019; 11:v11060530. [PMID: 31181645 PMCID: PMC6631704 DOI: 10.3390/v11060530] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2019] [Revised: 05/30/2019] [Accepted: 06/06/2019] [Indexed: 01/15/2023] Open
Abstract
Myxomatosis is a lethal disease in wild European and domestic rabbits (Oryctolagus cuniculus), which is caused by a Myxoma virus (MYXV) infection-a leporipoxvirus that is found naturally in some Sylvilagus rabbit species in South America and California. The introduction of MYXV into feral European rabbit populations of Australia and Europe, in the early 1950s, demonstrated the best-documented field example of host-virus coevolution, following a cross-species transmission. Recently, a new cross-species jump of MYXV has been suggested in both Great Britain and Spain, where European brown hares (Lepus europaeus) and Iberian hares (Lepus granatensis) were found dead with lesions consistent with those observed in myxomatosis. To investigate the possibility of a new cross-species transmission event by MYXV, tissue samples collected from a wild Iberian hare found dead in Spain (Toledo region) were analyzed and deep sequenced. Our results reported a new MYXV isolate (MYXV Toledo) in the tissues of this species. The genome of this new virus was found to encode three disruptive genes (M009L, M036L, and M152R) and a novel ~2.8 kb recombinant region, which resulted from an insertion of four novel poxviral genes towards the 3' end of the negative strand of its genome. From the open reading frames inserted into the MYXV Toledo virus, a new orthologue of a poxvirus host range gene family member was identified, which was related to the MYXV gene M064R. Overall, we confirmed the identity of a new MYXV isolate in Iberian hares, which, we hypothesized, was able to more effectively counteract the host defenses in hares and start an infectious process in this new host.
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Affiliation(s)
- Ana Águeda-Pinto
- CIBIO/InBio-Centro de Investigação em Biodiversidade e Recursos Genéticos, Universidade do Porto, Campus Agrário de Vairão, 4485-661 Vairão, Portugal.
- Departamento de Biologia, Faculdade de Ciências, Universidade do Porto, 4169-007 Porto, Portugal.
- Center for Immunotherapy, Vaccines, and Virotherapy (CIVV), The Biodesign Institute, Arizona State University, Tempe, AZ 85287, USA.
| | - Ana Lemos de Matos
- Center for Immunotherapy, Vaccines, and Virotherapy (CIVV), The Biodesign Institute, Arizona State University, Tempe, AZ 85287, USA.
| | - Mário Abrantes
- Center for Immunotherapy, Vaccines, and Virotherapy (CIVV), The Biodesign Institute, Arizona State University, Tempe, AZ 85287, USA.
| | - Simona Kraberger
- The Biodesign Center for Fundamental and Applied Microbiomics, Center for Evolution and Medicine and School of Life sciences, Arizona State University, Tempe, AZ 85287, USA.
| | - Maria A Risalde
- Dpto. de Anatomía y Anatomía Patológica Comparadas, Universidad de Córdoba, Agrifood Excellence International Campus (ceiA3), 14071 Córdoba, Spain.
| | - Christian Gortázar
- Instituto de Investigación en Recursos Cinegéticos IREC-CSIC-UCLM-JCCM, Ronda de Toledo, 28005 Ciudad Real, Spain.
| | - Grant McFadden
- Center for Immunotherapy, Vaccines, and Virotherapy (CIVV), The Biodesign Institute, Arizona State University, Tempe, AZ 85287, USA.
| | - Arvind Varsani
- The Biodesign Center for Fundamental and Applied Microbiomics, Center for Evolution and Medicine and School of Life sciences, Arizona State University, Tempe, AZ 85287, USA.
- Structural Biology Research Unit, Department of Clinical Laboratory Sciences, University of Cape Town, Cape Town 7701, South Africa.
| | - Pedro J Esteves
- CIBIO/InBio-Centro de Investigação em Biodiversidade e Recursos Genéticos, Universidade do Porto, Campus Agrário de Vairão, 4485-661 Vairão, Portugal.
- Departamento de Biologia, Faculdade de Ciências, Universidade do Porto, 4169-007 Porto, Portugal.
- CITS-Centro de Investigação em Tecnologias da Saúde, IPSN, CESPU, 4585-116 Gandra, Portugal.
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Abstract
1. Identifying general patterns of how and why survival rates vary across space and time is necessary to truly understand population dynamics of a species. However, this is not an easy task given the complexity and interactions of processes involved, and the interpopulation differences in main survival determinants. 2. Here, using European rabbits (Oryctolagus cuniculus) as a model and information from local studies, we investigated whether we could make inferences about trends and drivers of survival of a species that are generalizable to large spatio-temporal scales. To do this, we first focused on overall survival and then examined cause-specific mortalities, mainly predation and diseases, which may lead to those patterns. 3. Our results show that within the large-scale variability in rabbit survival, there exist general patterns that are explained by the integration of factors previously known to be important at the local level (i.e. age, climate, diseases, predation or density dependence). We found that both inter- and intrastudy survival rates increased in magnitude and decreased in variability as rabbits grow old, although this tendency was less pronounced in populations with epidemic diseases. Some causes leading to these higher mortalities in young rabbits could be the stronger effect of rainfall at those ages, as well as, other death sources like malnutrition or infanticide. 4. Predation is also greater for newborns and juveniles, especially in population without diseases. Apart from the effect of diseases, predation patterns also depended on factors, such as, density, season, and type and density of predators. Finally, we observed that infectious diseases also showed general relationships with climate, breeding (i.e. new susceptible rabbits) and age, although the association type varied between myxomatosis and rabbit haemorrhagic disease. 5. In conclusion, large-scale patterns of spatio-temporal variability in rabbit survival emerge from the combination of different factors that interrelate both directly and through density dependence. This highlights the importance of performing more comprehensive studies to reveal combined effects and complex relationships that help us to better understand the mechanisms underlying population dynamics.
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Affiliation(s)
- Zulima Tablado
- Departamento Biología de la Conservación, Estación Biológica de Doñana (CSIC), Avda Américo Vespucio s/n, 41092 Sevilla, Spain.
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Atkin JW, Radford AD, Coyne KP, Stavisky J, Chantrey J. Detection of squirrel poxvirus by nested and real-time PCR from red (Sciurus vulgaris) and grey (Sciurus carolinensis) squirrels. BMC Vet Res 2010; 6:33. [PMID: 20529323 DOI: 10.1186/1746-6148-6-33] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2009] [Accepted: 06/08/2010] [Indexed: 11/10/2022] Open
Abstract
Background Squirrel poxvirus (SQPV) is highly pathogenic to red squirrels (Sciurus vulgaris), and is a significant contributing factor to the local extinction of the species in most parts of England and Wales, where infection is endemic in Eastern grey squirrel (Sciurus carolinensis) populations. Although a nested PCR assay has been used successfully to study the epidemiology of SQPV, samples have a long processing time and the assay is not quantifiable. Results This project describes the design and optimization of a real-time PCR for SQPV. Comparison with the nested PCR showed the real-time assay to be more sensitive by one log and able to detect approximately 144 genome copies per mg of tissue. Conclusions The real-time PCR has been used to quantify viral genome load in tissues from diseased and apparently healthy red and grey squirrels, and suggests that the titre of virus in tissues from diseased red squirrels is considerably higher than that found even in a grey squirrel with cutaneous lesions.
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García-bocanegra I, Astorga RJ, Napp S, Casal J, Huerta B, Borge C, Arenas A. Myxomatosis in wild rabbit: Design of control programs in Mediterranean ecosystems. Prev Vet Med 2010; 93:42-50. [DOI: 10.1016/j.prevetmed.2009.09.013] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2008] [Revised: 08/27/2009] [Accepted: 09/14/2009] [Indexed: 11/21/2022]
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WILLIAMS CK, DAVEY CC, MOORE RJ, HINDS LA, SILVERS LE, KERR PJ, FRENCH N, HOOD GM, PECH RP, KREBS CJ. Population responses to sterility imposed on female European rabbits. J Appl Ecol 2007. [DOI: 10.1111/j.1365-2664.2006.01264.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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van Leeuwen BH, Kerr PJ. Prospects for fertility control in the European rabbit (Oryctolagus cuniculus) using myxoma virus-vectored immunocontraception. Wildl Res 2007. [DOI: 10.1071/wr06167] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Research over the last 15 years has examined whether fertility control can reduce overabundant rabbit populations and whether an effective immunocontraceptive agent can be developed and delivered. The results of this research indicate that for fertility control to have an environmental impact at least 80% of females will need to be infertile and that this infertility will need to be permanent. Epidemiological studies suggest that this level of infertility may be very difficult to obtain with a recombinant myxoma virus because of competition with field strains of virus. Research with laboratory rabbits using recombinant myxoma virus to deliver an immunocontraceptive antigen demonstrated that it was possible to obtain the required level of infertility using rabbit zona pellucida C as an antigen. However, only ~50% of animals remained infertile in the medium term. Further research on delivery vector and antigen selection would be needed to produce a practical immunocontraceptive virus for laboratory testing. Such a virus would then need to be optimised for transmissibility before it would be suitable for field testing.
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Angulo E, Bárcena J. Towards a unique and transmissible vaccine against myxomatosis and rabbit haemorrhagic disease for rabbit populations. Wildl Res 2007. [DOI: 10.1071/wr06160] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Currently available vaccines against myxomatosis and rabbit hemorrhagic disease virus (RHDV) are not suited to immunise wild rabbit populations, as vaccines need to be delivered individually by conventional veterinary practices. As an alternative approach, research in Spain has focused on the development of a transmissible vaccine. A recombinant virus has been constructed based on a naturally attenuated myxoma virus (MV) field strain, expressing the RHDV capsid protein (VP60). Following inoculation of rabbits, the recombinant virus (MV-VP60) induced specific antibody responses against MV and RHDV, conferring protection against lethal challenges with both viruses. Furthermore, the recombinant MV-VP60 virus showed a limited horizontal transmission capacity, either by direct contact or in a flea-mediated process, promoting immunisation of contact uninoculated animals. Efficacy and safety of the vaccine have been extensively evaluated under laboratory conditions and in a limited field trial. The development of the transmissible vaccine strategy and the steps being taken to obtain the marketing authorisation for the vaccine in the European Union are presented in this review.
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