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Dalton K.P.,University of Oviedo | Abrantes J.,University of Porto | Lopes A.M.,University of Porto | Lopes A.M.,University of Nantes | And 5 more authors.
Archives of Virology | Year: 2015

We report the complete genome sequences of two isolates (RHDV-N11 and CBVal16) of variant rabbit hemorrhagic disease virus (RHDVb). Isolate N11 was detected in young domestic animals during a rabbit hemorrhagic disease (RHD) outbreak that occurred in 2011 on a rabbit farm in Navarra, Spain, while CBVal16 was isolated from a wild rabbit found dead in Valpaços, Northern Portugal, a year later. The viral sequences reported show 84.8–85.1 % and 78.3–78.5 % identity to RHDVAst/89 and RCV-A1 MIC-07, representative members of the pathogenic genogroup 1 RHDV and apathogenic rabbit calicivirus, respectively. In comparison with other RHDV isolates belonging to the previously known genogroups 1–6, RHDVb shows marked phenotypic differences, as it causes disease preferentially in young rabbits under 40 days of age and shows modified red blood cell agglutination profiles as well as antigenic differences that allow this variant to escape protection by the currently available vaccines. © 2015, Springer-Verlag Wien. Source

Esteves P.J.,University of Porto | Esteves P.J.,Institute Investigacao e Formacao Avancada em Ciencias e Tecnologias da Saude CESPU | Lopes A.M.,University of Porto | Lopes A.M.,French Institute of Health and Medical Research | And 2 more authors.
Viruses | Year: 2014

Rabbit hemorrhagic disease is caused by a calicivirus, rabbit hemorrhagic disease virus (RHDV), which is responsible for high mortality in domestic and wild European rabbits (Oryctolagus cuniculus). RHDV strains were sequenced from wild European rabbits (Oryctolagus cuniculus algirus) collected in the Azorean island of Pico, Portugal. Phylogenetic analyses showed that the Pico RHDV strains diverge from all of the others described so far, but cluster with the genogroups 1-5 (G1-G5). The genetic distance between the Pico RHDV sequences and each G1, G2 and G3-G5 genogroup (~0.08) is compatible with an RHDV introduction at least 17 years ago. Our results show that in Pico, RHDV is the outcome of an independent evolution from the original RHDV strain that appeared in its European rabbit population. These are the first sequences of RHDV obtained in the subspecies O. c. algirus, outside of its original region, the Iberian Peninsula. Furthermore, we discuss the risk of rabbit translocations from the Azores to the Iberian Peninsula, where the rabbit wild populations are suffering high mortalities. © 2014 by the authors; licensee MDPI, Basel, Switzerland. Source

Almeida T.,University of Porto | Lopes A.M.,University of Porto | Lopes A.M.,University of Nantes | Magalhaes M.J.,University of Porto | And 7 more authors.
Infection, Genetics and Evolution | Year: 2015

Previous genetic characterization of rabbit haemorrhagic disease virus (RHDV) from Azores, Portugal, revealed the presence of genogroup 3-5 (G3-G5) like strains. These strains differed from the genogroup 1 (G1) strains circulating in mainland Portugal, suggesting an independent evolution of RHDV in Azores. More recently, the new variant RHDV (RHDVb) was detected in Azores. In mainland Portugal, current circulating strains resulted from recombination events between RHDVb and non-pathogenic or pathogenic G1 strains. To characterize the RHDVb strains from Azores, a ~2.5. kb fragment of the RHDV genome (nucleotide positions 4873-7323), including the complete sequence of the capsid gene VP60 (nucleotide positions 5305-7044), was amplified and sequenced. Samples were obtained from rabbits found dead in the field between December 2014 and March 2015 in the Azorean islands Flores, Graciosa, São Jorge, Terceira, Faial, Pico, São Miguel and Santa Maria. For VP60, the highest homology was found with Iberian RHDVb strains, while the upstream fragment revealed high similarity (~95%) with Iberian G1 strains. Phylogenetic reconstruction based either on VP60 or VP10 grouped the Azorean strains with Iberian RHDVb strains. For the fragment upstream of VP60, the Azorean strains grouped with G1. Our results show that the RHDVb strains circulating in Azores are G1/RHDVb recombinants and we hypothesize that such strains had their origin in Iberian strains. The geographic isolation of Azores suggests that arrival of RHDVb was man-mediated. A network analysis further allowed us to trace virus dispersion in Azores: from an initial outbreak in Graciosa, RHDVb spread to São Jorge and Faial, to Terceira, Flores and Santa Maria, and finally to Pico; dispersion to São Miguel occurred later from Terceira. As the consequences of the presence of G1/RHDVb strains in Azores are unpredictable, we suggest a continued monitoring and characterization of RHD outbreaks. © 2015 Elsevier B.V. Source

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