scholarly journals A Quadruplex qPCR for Detection and Differentiation of Classic and Natural Recombinant Myxoma Virus Strains of Leporids

2021 ◽  
Vol 22 (21) ◽  
pp. 12052
Author(s):  
Fábio A. Abade dos Santos ◽  
Carina L. Carvalho ◽  
Francisco Parra ◽  
Kevin P. Dalton ◽  
Maria C. Peleteiro ◽  
...  
Keyword(s):  
Real Time ◽  
Housekeeping Gene ◽  
Myxoma Virus ◽  
European Rabbit ◽  
Fast Method ◽  
Wild Rabbit ◽  
Viral Dna ◽  
Eukaryotic Organisms ◽  
Virus Strains ◽  
Iberian Hare

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.

scholarly journals Detection of Recombinant Hare Myxoma Virus in Wild Rabbits (Oryctolagus cuniculus algirus)

Viruses ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 1127
Author(s):  
Fábio A. Abade dos Santos ◽  
Carina L. Carvalho ◽  
Andreia Pinto ◽  
Ranjit Rai ◽  
Madalena Monteiro ◽  
...  
Keyword(s):  
Myxoma Virus ◽  
Virus Infectivity ◽  
Sequencing Analysis ◽  
Wild Rabbit ◽  
Mainland Portugal ◽  
Viral Particles ◽  
Domestic Rabbits ◽  
Virus Strains ◽  
Iberian Hare ◽  
Species Segregation

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.

scholarly journals Changes in the virulence of myxoma virus strains in Britain

1987 ◽  
Vol 98 (1) ◽  
pp. 113-117 ◽  
Author(s):  
J. Ross ◽  
M. F. Sanders
Keyword(s):  
Myxoma Virus ◽  
Wild Rabbit ◽  
National Surveys ◽  
Testing Method ◽  
Development Of Resistance ◽  
Similar Survey ◽  
Virus Strains

SUMMARYNational surveys of the virulence of field strains of myxoma virus were carried out in 1975 (128 virus strains) and in 1981 (123 strains), using the virulence testing method employed in a similar survey in 1962. Results showed that the virulence of field strains had increased between 1962 and 1975, and again between 1975 and 1981. The increases in virulence are thought to be a result of the development of resistance to myxomatosis in wild rabbit populations. The effects of the changes in virulence and resistance are discussed.

scholarly journals Myxomatosis: the introduction of the European rabbit flea Spilopsyllus cuniculi (Dale) into wild rabbit populations in Australia

1971 ◽  
Vol 69 (3) ◽  
pp. 331-346 ◽  
Author(s):  
W. R. Sobey ◽  
Dorothy Conolly
Keyword(s):  
Breeding Season ◽  
New South ◽  
New South Wales ◽  
Release Site ◽  
Myxoma Virus ◽  
European Rabbit ◽  
Wild Rabbit ◽  
South Wales ◽  
Breeding Seasons

SUMMARY1. The European rabbit flea Spilopsyllus cuniculi (Dale) bred successfully in wild rabbits on three properties in New South Wales and, within two breeding seasons, almost every rabbit shot within a quarter of a mile of a release site was infested.2. It was demonstrated that the flea transmitted myxoma virus in the field.3. In areas where more than 75 % of the rabbits shot at the beginning of the breeding season were flea-infested and myxoma virus was present, populations failed to show the expected summer build-up.

Myxoma virus and rabbit haemorrhagic disease virus 2 coinfection in a European wild rabbit (Oryctolagus cuniculus algirus), Portugal

2020 ◽  
Vol 8 (1) ◽  
pp. e001002 ◽  
Author(s):  
Carina Luisa Carvalho ◽  
Fábio Alexandre Abade dos Santos ◽  
Teresa Fagulha ◽  
Paulo Carvalho ◽  
Paula Mendonça ◽  
...  
Keyword(s):  
Disease Virus ◽  
Oryctolagus Cuniculus ◽  
Rare Event ◽  
Myxoma Virus ◽  
European Rabbit ◽  
Wild Rabbit ◽  
Rabbit Haemorrhagic Disease Virus ◽  
Sample Collection ◽  
Rabbit Haemorrhagic Disease ◽  
Haemorrhagic Disease

Myxoma virus (MYXV) and rabbit haemorrhagic disease virus 2 (RHDV2) are two major pathogens that affect the European rabbit (Oryctolagus cuniculus). Between August 2017 and August 2019, 1166 wild rabbits (971 legally hunted and 195 found dead) were tested by PCR-based methods for MYXV and RHDV2 within the scope of an ongoing surveillance programme on wild leporids in Portugal. Despite never having been reported before and being considered a rare event, coinfection by RHDV2 and MYXV was detected in one juvenile wild rabbit found dead in the Évora district located in Alentejo. The relative frequency of coinfection in the group of diseased rabbits (found dead in the field) was 0.52 per cent (1/195). The positivity percentage of each single virus was much higher, namely, 14.36 per cent (28/195) for MYXV and 55.38 per cent (108/195) for RHDV2, within the 2 years of sample collection considered.

scholarly journals Genetic characterization of a recombinant myxoma virus leap into the Iberian hare (Lepus granatensis)

2019 ◽  
Author(s):  
Ana Águeda-Pinto ◽  
Ana Lemos de Matos ◽  
Mário Abrantes ◽  
Simona Kraberger ◽  
Maria A. Risalde ◽  
...  
Keyword(s):  
Myxoma Virus ◽  
Open Reading Frames ◽  
Lepus Europaeus ◽  
European Rabbit ◽  
New Host ◽  
Tissue Samples ◽  
Lepus Granatensis ◽  
Domestic Rabbits ◽  
Iberian Hare

AbstractMyxomatosis is a lethal disease of wild European and domestic rabbits (Oryctolagus cuniculus) caused by a Myxoma virus (MYXV) infection, a leporipoxvirus that is found naturally in someSylvilagusrabbit species in South America and California. The introduction of MYXV in the early 1950s into feral European rabbit populations in Australia and Europe demonstrate 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 report a new MYXV strain (MYXV Toledo) in the tissues of this species. The genome of this new strain encodes three disrupted genes (M009L,M036LandM152R) and a novel 2.8 KB recombinant region that resulted from an insertion of four novel poxviral genes towards the 5’ end of its genome. From the open reading frames inserted into the MYXV Toledo strain, a new orthologue of a poxvirus host range gene family member was identified which is related to the MYXV geneM064R. Overall, we confirmed the identity of a new MYXV strain in Iberian hares that we hypothesize was able to more effectively counteract the host defenses in hares and start an infectious process in this new host.

scholarly journals Evolution and Phylogeography of the Nonpathogenic Calicivirus RCV-A1 in Wild Rabbits in Australia

2010 ◽  
Vol 84 (23) ◽  
pp. 12397-12404 ◽  
Author(s):  
Marlene Jahnke ◽  
Edward C. Holmes ◽  
Peter J. Kerr ◽  
John D. Wright ◽  
Tanja Strive
Keyword(s):  
Myxoma Virus ◽  
European Rabbit ◽  
Rabbit Hemorrhagic Disease Virus ◽  
Recent Common Ancestor ◽  
Hemorrhagic Disease ◽  
Evolutionary Analysis ◽  
Wild Rabbit ◽  
Most Recent Common Ancestor ◽  
Capsid Sequence ◽  
Australian Continent

ABSTRACT Despite its potential importance for the biological control of European rabbits, relatively little is known about the evolution and molecular epidemiology of rabbit calicivirus Australia 1 (RCV-A1). To address this issue we undertook an extensive evolutionary analysis of 36 RCV-A1 samples collected from wild rabbit populations in southeast Australia between 2007 and 2009. Based on phylogenetic analysis of the entire capsid sequence, six clades of RCV-A1 were defined, each exhibiting strong population subdivision. Strikingly, our estimates of the time to the most recent common ancestor of RCV-A1 coincide with the introduction of rabbits to Australia in the mid-19th century. Subsequent divergence events visible in the RCV-A1 phylogenies likely reflect key moments in the history of the European rabbit in Australia, most notably the bottlenecks in rabbit populations induced by the two viral biocontrol agents used on the Australian continent, myxoma virus and rabbit hemorrhagic disease virus (RHDV). RCV-A1 strains therefore exhibit strong phylogeographic separation and may constitute a useful tool to study recent host population dynamics and migration patterns, which in turn could be used to monitor rabbit control in Australia.

scholarly journals Genetic Characterization of a Recombinant Myxoma Virus in the Iberian Hare (Lepus granatensis)

Viruses ◽  
2019 ◽  
Vol 11 (6) ◽  
pp. 530 ◽  
Author(s):  
Ana Águeda-Pinto ◽  
Ana Lemos de Matos ◽  
Mário Abrantes ◽  
Simona Kraberger ◽  
Maria A. Risalde ◽  
...  
Keyword(s):  
Myxoma Virus ◽  
Open Reading Frames ◽  
Lepus Europaeus ◽  
European Rabbit ◽  
New Host ◽  
Tissue Samples ◽  
Lepus Granatensis ◽  
Domestic Rabbits ◽  
Iberian Hare

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.

scholarly journals Detection of Recombinant Hare Myxoma Virus in Wild Rabbits (Oryctolagus cuniculus algirus)

2020 ◽  
Author(s):  
Fábio A. Abade dos Santos ◽  
Carina L. Carvalho ◽  
Andreia Pinto ◽  
Ranjit Rai ◽  
Madalena Monteiro ◽  
...  
Keyword(s):  
Myxoma Virus ◽  
Virus Infectivity ◽  
Wild Rabbit ◽  
R Gene ◽  
Viral Particles ◽  
Domestic Rabbits ◽  
South Portugal ◽  
Iberian Hare ◽  
Continue Monitoring ◽  
Species Segregation

In late 2018, an epidemic myxomatosis outbreak emerged on the Iberian Peninsula leading to high mortality in Iberian hare populations. Soon, a recombinant virus (MYXV-Tol or ha-MYXV) was identified, harboring a 2.8 kb insertion containing evolved duplicates of M060L, M061L, M064L, and M065L from MYXV. Since 2017, 1616 rabbits and 82 hares were tested by a qPCR directed to M000.5L/R gene, conserved in MYXV and MYXV-Tol/ ha-MYXV strains. A subset (20%) of the positive samples was tested for the insert with MYXV being detected in rabbits and recombinant MYXV in hares. Recently, two wild rabbits found dead in South Portugal, showing skin oedema and pulmonary lesions tested positive for the 2.8 Kb insert. Sequencing showed 100% similarity with the insert sequences described in Iberian hares from Spain. Viral particles were observed in the lungs of both rabbits by electron microscopy, and isolation in RK13 cells showed virus infectivity. Despite the analysis of recombinant MYXV genomes may predict its 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, which raises serious concerns for the future of the Iberian wild leporids and emphasizes the need to continue monitoring MYXV and recombinant MYXV in both species.

scholarly journals The differential transmissibility of myxoma virus strains of differing virulence grades by the rabbit flea Spilopsyllus cuniculi (Dale)

1975 ◽  
Vol 75 (2) ◽  
pp. 237-247 ◽  
Author(s):  
A. R. Mead-Briggs ◽  
J. A. Vaughan
Keyword(s):  
Host Resistance ◽  
Oryctolagus Cuniculus ◽  
Selective Advantage ◽  
Myxoma Virus ◽  
Laboratory Studies ◽  
Natural Conditions ◽  
Male And Female ◽  
The Mean ◽  
Virus Strains ◽  
Sampling Times

SUMMARYLaboratory studies showed that few rabbit fleas (Spilopsyllus cuniculi (Dale)) transmitted myxomatosis after removal from wild rabbits (Oryctolagus cuniculus (L)) that had been infected for fewer than 10–12 days, irrespective of the virulence of the myxoma virus strain involved. Rabbits infected with fully virulent (Grade I) strains died within 10–15 days and few fleas from these hosts became infective; averaging all the samples taken, 12% of the fleas were infective. Also, few fleas acquired infectivity on individual rabbits which recovered from infection with attenuated strains; the mean was 8% infective. Rabbits which died between 17 and 44 days after infection had higher proportions of infective fleas at all sampling times; the mean was 42% infective. Male and female fleas transmitted virus with equal efficiency.For rabbits infected with any of the attenuated virus strains the mean percentage of infective fleas was inversely related to the survival time of the host. Rabbits infected with moderately attenuated strains (Grades IIIA and IIIB) had, on average, the highest proportion of infective fleas; hence such strains have a selective advantage and have become predominant under natural conditions in Britain. The changes that might occur if there is an increase in host resistance to myxomatosis are discussed.

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