Phylogeny of Spanish swine influenza viruses isolated from respiratory disease outbreaks and evolution of swine influenza virus within an endemically infected farm

GE Martin-Valls, M Simon-Grife, Sander van Boheemen, Miranda de Graaf, Theo Bestebroer, N Busquets, M Martin, J Casal, Ron Fouchier, E Mateu

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In the present study, outbreaks of respiratory disease were investigated for the presence of swine influenza virus (SIV). In 14 cases the circulating SIV strains were isolated, fully sequenced and compared with other known SIVs. The viruses causing the outbreaks belonged to the H1N1 (including human pandemic H1N1), H3N2 and H1N2 subtypes. In 11/14 cases the phylogenetic analyses indicated the occurrence of probable reassortment events. In the second part of the study, the genetic evolution of H1N1 SIV was assessed in a longitudinal study in closed groups of pigs over six months. Sequencing of the 22 isolates indicated co-circulation of two different variants for the same virus, as well as the emergence of SIV reassortants at certain time-points. These results indicate that reassortment events in SIV are common, and point towards the need for a better understanding of the epidemiology of SIV, particularly in endemic farms. (C) 2014 Elsevier B.V. All rights reserved.
Original languageUndefined/Unknown
Pages (from-to)266-277
Number of pages12
JournalVeterinary Microbiology
Issue number3-4
Publication statusPublished - 2014

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