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Abade Dos Santos FA, Santos N, Carvalho CL, Martinez-Haro M, Gortázar C, García-Bocanegra I, Capucci L, Duarte M, Alves PC. Retrospective serological and molecular survey of myxoma or antigenically related virus in the Iberian hare, Lepus granatensis. Transbound Emerg Dis 2022; 69:3637-3650. [PMID: 36219552 PMCID: PMC10092749 DOI: 10.1111/tbed.14734] [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: 12/17/2021] [Revised: 08/10/2022] [Accepted: 10/05/2022] [Indexed: 02/07/2023]
Abstract
The 2018 outbreak of myxomatosis in the Iberian hare (Lepus granatensis) has been hypothesized to originate from a species jump of the rabbit-associated myxoma virus (MYXV), after natural recombination with an unknown poxvirus. Iberian hares were long considered resistant to myxomatosis as no prior outbreaks were reported. To provide insights into the emergence of this recombinant virus (ha-MYXV), we investigated serum samples from 451 Iberian hares collected over two time periods almost two decades apart, 1994-1999 and 2017-2019 for the presence of antibodies and MYXV-DNA. First, we screened all serum samples using a rabbit commercial indirect ELISA (iELISA) and then tested a subset of these samples in parallel using indirect immunofluorescence test (IFT), competitive ELISA (cELISA) and qPCR targeting M000.5L/R gene conserved in MYXV and ha-MYXV. The cut-off of iELISA relative index 10 = 6.1 was selected from a semiparametric finite mixture analysis aiming to minimize the probability of false positive results. Overall, MYXV related-antibodies were detected in 57 hares (12.6%) including 38 apparently healthy hares (n = 10, sampled in 1994-1999, none MYXV-DNA positive, and n = 28 sampled in 2017-2019 of which four were also ha-MYXV-DNA positive) and 19 found-dead and ha-MYXV-DNA-positive sampled in 2018-2019. Interestingly, four seronegative hares sampled in 1997 were MYXV-DNA positive by qPCR, the result being confirmed by sequencing of three of them. For the Iberian hares hunted or live trapped (both apparently health), seroprevalence was significantly higher in 2017-2019 (13.0%, CI95% 9.2-18.2%) than in 1994-1999 (5.4%, CI95% 3.0-9.6%) (p = .009). Within the second period, seroprevalence was significantly higher in 2019 compared to 2017 (24.7 vs 1.7% considering all the sample, p = .007), and lower during the winter than the autumn (p < .001). While our molecular and serological results show that Iberian hares have been in contact with MYXV or an antigenically similar virus at least since 1996, they also show an increase in seroprevalence in 2018-2019. The remote contact with MYXV may have occurred with strains that circulated in rabbits, or with unnoticed strains already circulating in Iberian hare populations. This work strongly suggests the infection of Iberian hares with MYXV or an antigenically related virus, at least 20 years before the severe virus outbreaks were registered in 2018.
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Affiliation(s)
- Fábio A Abade Dos Santos
- Instituto Nacional de Investigação Agrária e Veterinária, I.P. (INIAV, I.P.), Oeiras, Portugal.,Centro de Investigação Interdisciplinar em Sanidade Animal (CIISA), Faculdade de Medicina Veterinária, Universidade de Lisboa, Avenida da Universidade Técnica, Lisboa, Portugal.,Associate Laboratory for Animal and Veterinary Sciences (AL4AnimalS), Portugal
| | - Nuno Santos
- CIBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, InBIO Laboratório Associado, Campus de Vairão, Universidade do Porto, Vairão, Portugal.,BIOPOLIS Program in Genomics, Biodiversity and Land Planning, CIBIO, Campus de Vairão, Vairão, Portugal
| | - Carina L Carvalho
- Instituto Nacional de Investigação Agrária e Veterinária, I.P. (INIAV, I.P.), Oeiras, Portugal
| | - Monica Martinez-Haro
- Instituto Regional de Investigación y Desarrollo Agroalimentario y Forestal de Castilla-La Mancha (IRIAF). Centro de Investigación Agroambiental El Chaparrillo, Ciudad Real, Spain
| | - Christian Gortázar
- SaBio Instituto de Investigación en Recursos Cinegéticos IREC (UCLM & CSIC), Ciudad Real, Spain
| | | | - Lorenzo Capucci
- Istituto Zooprofilattico Sperimentale della Lombardia e dell'Emilia Romagna and OIE Reference Laboratory for Rabbit Haemorrhagic Disease, Brescia, Italy
| | - Margarida Duarte
- Instituto Nacional de Investigação Agrária e Veterinária, I.P. (INIAV, I.P.), Oeiras, Portugal.,Centro de Investigação Interdisciplinar em Sanidade Animal (CIISA), Faculdade de Medicina Veterinária, Universidade de Lisboa, Avenida da Universidade Técnica, Lisboa, Portugal.,Associate Laboratory for Animal and Veterinary Sciences (AL4AnimalS), Portugal
| | - Paulo Célio Alves
- CIBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, InBIO Laboratório Associado, Campus de Vairão, Universidade do Porto, Vairão, Portugal.,BIOPOLIS Program in Genomics, Biodiversity and Land Planning, CIBIO, Campus de Vairão, Vairão, Portugal.,Departamento de Biologia, Faculdade de Ciências, Universidade do Porto, Porto, Portugal.,EBM, Estação. Biológica de Mértola, Mértola, Portugal
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Abade dos Santos FA, Carvalho CL, Parra F, Dalton KP, Peleteiro MC, Duarte MD. A Quadruplex qPCR for Detection and Differentiation of Classic and Natural Recombinant Myxoma Virus Strains of Leporids. Int J Mol Sci 2021; 22:ijms222112052. [PMID: 34769480 PMCID: PMC8584577 DOI: 10.3390/ijms222112052] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2021] [Revised: 11/04/2021] [Accepted: 11/05/2021] [Indexed: 01/19/2023] Open
Abstract
A natural recombinant myxoma virus (referred to as ha-MYXV or MYXV-Tol08/18) emerged in the Iberian hare (Lepus granatensis) and the European rabbit (Oryctolagus cuniculus) in late 2018 and mid-2020, respectively. This new virus is genetically distinct from classic myxoma virus (MYXV) strains that caused myxomatosis in rabbits until then, by acquiring an additional 2.8 Kbp insert within the m009L gene that disrupted it into ORFs m009L-a and m009L-b. To distinguish ha-MYXV from classic MYXV strains, we developed a robust qPCR multiplex technique that combines the amplification of the m000.5L/R duplicated gene, conserved in all myxoma virus strains including ha-MYXV, with the amplification of two other genes targeted by the real-time PCR systems designed during this study, specific either for classic MYXV or ha-MYXV strains. The first system targets the boundaries between ORFs m009L-a and m009L-b, only contiguous in classic strains, while the second amplifies a fragment within gene m060L, only present in recombinant MYXV strains. All amplification reactions were validated and normalized by a fourth PCR system directed to a housekeeping gene (18S rRNA) conserved in eukaryotic organisms, including hares and rabbits. The multiplex PCR (mPCR) technique described here was optimized for Taqman® and Evagreen® systems allowing the detection of as few as nine copies of viral DNA in the sample with an efficiency > 93%. This real-time multiplex is the first fast method available for the differential diagnosis between classic and recombinant MYXV strains, also allowing the detection of co-infections. The system proves to be an essential and effective tool for monitoring the geographical spread of ha-MYXV in the hare and wild rabbit populations, supporting the management of both species in the field.
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Affiliation(s)
- Fábio A. Abade dos Santos
- Centro de Investigação Interdisciplinar em Sanidade Animal (CIISA), Faculdade de Medicina Veterinária, Universidade de Lisboa, Avenida da Universidade Técnica, 1300-477 Lisboa, Portugal; (M.C.P.); (M.D.D.)
- Instituto Nacional de Investigação Agrária e Veterinária (INIAV, I.P.), Av. da República, Quinta do Marquês, 2780-157 Oeiras, Portugal;
- Instituto Universitario de Biotecnología de Asturias (IUBA), Departamento de Bioquímica y Biología Molecular, Universidad de Oviedo, 33003 Oviedo, Spain; (F.P.); (K.P.D.)
- Correspondence: ; Tel.: +351-21-440-3500
| | - Carina L. Carvalho
- Instituto Nacional de Investigação Agrária e Veterinária (INIAV, I.P.), Av. da República, Quinta do Marquês, 2780-157 Oeiras, Portugal;
| | - Francisco Parra
- Instituto Universitario de Biotecnología de Asturias (IUBA), Departamento de Bioquímica y Biología Molecular, Universidad de Oviedo, 33003 Oviedo, Spain; (F.P.); (K.P.D.)
| | - Kevin P. Dalton
- Instituto Universitario de Biotecnología de Asturias (IUBA), Departamento de Bioquímica y Biología Molecular, Universidad de Oviedo, 33003 Oviedo, Spain; (F.P.); (K.P.D.)
| | - Maria C. Peleteiro
- Centro de Investigação Interdisciplinar em Sanidade Animal (CIISA), Faculdade de Medicina Veterinária, Universidade de Lisboa, Avenida da Universidade Técnica, 1300-477 Lisboa, Portugal; (M.C.P.); (M.D.D.)
| | - Margarida D. Duarte
- Centro de Investigação Interdisciplinar em Sanidade Animal (CIISA), Faculdade de Medicina Veterinária, Universidade de Lisboa, Avenida da Universidade Técnica, 1300-477 Lisboa, Portugal; (M.C.P.); (M.D.D.)
- Instituto Nacional de Investigação Agrária e Veterinária (INIAV, I.P.), Av. da República, Quinta do Marquês, 2780-157 Oeiras, Portugal;
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Abade Dos Santos FA, Carvalho CL, Monteiro M, Carvalho P, Mendonça P, Peleteiro MDC, Duarte MD. Recombinant myxoma virus infection associated with high mortality in rabbit farming (Oryctolagus cuniculus). Transbound Emerg Dis 2020; 68:2616-2621. [PMID: 33119958 DOI: 10.1111/tbed.13899] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Revised: 10/24/2020] [Accepted: 10/25/2020] [Indexed: 12/01/2022]
Abstract
Myxomatosis is an emergent disease in the Iberian hare, having been considered a rabbit disease for decades. Genome sequencing of the strains obtained from Iberian hares with myxomatosis showed these to be distinct from the classical ones that circulated in rabbits since the virus introduction in Europe, in 1952. The main genomic difference in this natural recombinant hare myxoma virus (ha-MYXV) is the presence of an additional 2.8 kb region disrupting the M009L gene and adding a set of genes homologous to the myxoma virus (MYXV) genes M060R, M061R, M064R, M065R and M066R originated in Poxviruses. After the emergence of this recombinant virus (ha-MYXV) in hares, in the summer of 2019, the ha-MYXV was not detected in rabbit surveys, suggesting an apparent species segregation with the MYXV classic strains persistently circulating in rabbits. Recently, a group of six unvaccinated European rabbits (Oryctolagus cuniculus cuniculus) from a backyard rabbitry in South Portugal developed signs of myxomatosis (anorexia, dyspnoea, oedema of eyelids, head, ears, external genitals and anus, and skin myxomas in the base of the ears). Five of them died within 24-48 hr of symptom onset. Molecular analysis revealed that only the recombinant MYXV was present. This is the first documented report of a recombinant hare myxoma virus in farm rabbits associated with high mortality, which increases the concern for the future of both the Iberian hare and wild rabbits and questions the safety of the rabbit industry. This highlights the urgent need to evaluate the efficacy of available vaccines against this new MYXV.
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Affiliation(s)
- Fábio A Abade Dos Santos
- INIAV, I.P. National Institute of Agrarian and Veterinarian Research, Oeiras, Portugal.,Centre for Interdisciplinary Research in Animal Health, Faculty of Veterinary Medicine of Lisbon, CIISA, Lisboa, Portugal.,Instituto Universitario de Biotecnología de Asturias (IUBA), Departamento de Bioquímica y Biología Molecular, Universidad de Oviedo, Oviedo, Spain
| | - Carina L Carvalho
- INIAV, I.P. National Institute of Agrarian and Veterinarian Research, Oeiras, Portugal
| | - Madalena Monteiro
- INIAV, I.P. National Institute of Agrarian and Veterinarian Research, Oeiras, Portugal
| | - Paulo Carvalho
- INIAV, I.P. National Institute of Agrarian and Veterinarian Research, Oeiras, Portugal
| | - Paula Mendonça
- INIAV, I.P. National Institute of Agrarian and Veterinarian Research, Oeiras, Portugal
| | | | - Margarida D Duarte
- INIAV, I.P. National Institute of Agrarian and Veterinarian Research, Oeiras, Portugal.,Centre for Interdisciplinary Research in Animal Health, Faculty of Veterinary Medicine of Lisbon, CIISA, Lisboa, Portugal
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Detection of recombinant Hare Myxoma Virus in wild rabbits ( Oryctolagus cuniculus algirus). Viruses 2020; 12:v12101127. [PMID: 33028004 PMCID: PMC7600370 DOI: 10.3390/v12101127] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2020] [Revised: 09/26/2020] [Accepted: 10/02/2020] [Indexed: 11/29/2022] Open
Abstract
In late 2018, an epidemic myxomatosis outbreak emerged on the Iberian Peninsula leading to high mortality in Iberian hare populations. A recombinant Myxoma virus (strains MYXV-Tol and ha-MYXV) was rapidly identified, harbouring a 2.8 kbp insertion containing evolved duplicates of M060L, M061L, M064L, and M065L genes from myxoma virus (MYXV) or other Poxviruses. Since 2017, 1616 rabbits and 125 hares were tested by a qPCR directed to M000.5L/R gene, conserved in MYXV and MYXV-Tol/ha-MYXV strains. A subset of the positive samples (20%) from both species was tested for the insert with MYXV being detected in rabbits and the recombinant MYXV in hares. Recently, three wild rabbits were found dead South of mainland Portugal, showing skin oedema and pulmonary lesions that tested positive for the 2.8 kbp insert. Sequencing analysis showed 100% similarity with the insert sequences described in Iberian hares from Spain. Viral particles were observed in the lungs and eyelids of rabbits by electron microscopy, and isolation in RK13 cells attested virus infectivity. Despite that the analysis of complete genomes may predict the recombinant MYXV strains’ ability to infect rabbit, routine analyses showed species segregation for the circulation of MYXV and recombinant MYXV in wild rabbit and in Iberian hares, respectively. This study demonstrates, however, that recombinant MYXV can effectively infect and cause myxomatosis in wild rabbits and domestic rabbits, raising serious concerns for the future of the Iberian wild leporids while emphasises the need for the continuous monitoring of MYXV and recombinant MYXV in both species.
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