Swine influenza viruses isolated in 1983, 2002 and 2009 in Sweden exemplify different lineages
1 National Veterinary Institute, Ulls väg 2B, 75189 Uppsala, Sweden
2 Department of Virology, Central Agricultural Office, Veterinary Diagnostic Directorate, Tábornok u. 2., H-1149 Budapest, Hungary
3 Department of Microbiology, Central Agricultural Office, Veterinary Diagnostic Directorate, Bornemissza u. 3-7, H-4031 Debrecen, Hungary
4 Department of Biomedical Sciences and Veterinary Public Health, Division of Microbiology and Food Safety, Swedish University of Agricultural Sciences, Box 7036, S-75007 Uppsala, Sweden
5 Department of Clinical Sciences, Swedish University of Agricultural Sciences, Box 7054, S-75007 Uppsala, Sweden
Acta Veterinaria Scandinavica 2010, 52:65 doi:10.1186/1751-0147-52-65Published: 14 December 2010
Swine influenza virus isolates originating from outbreaks in Sweden from 1983, 2002 and 2009 were subjected to nucleotide sequencing and phylogenetic analysis. The aim of the studies was to obtain an overview on their potential relatedness as well as to provide data for broader scale studies on swine influenza epidemiology. Nonetheless, analyzing archive isolates is justified by the efforts directed to the comprehension of the appearance of pandemic H1N1 influenza virus. Interestingly, this study illustrates the evolution of swine influenza viruses in Europe, because the earliest isolate belonged to 'classical' swine H1N1, the subsequent ones to Eurasian 'avian-like' swine H1N1 and reassortant 'avian-like' swine H1N2 lineages, respectively. The latter two showed close genetic relatedness regarding their PB2, HA, NP, and NS genes, suggesting common ancestry. The study substantiates the importance of molecular surveillance for swine influenza viruses.