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Research article - Peer-reviewed, 2008

Molecular characterization of highly pathogenic H5N1 avian influenza viruses isolated in Sweden in 2006

Kiss, István; Gyarmati, Péter; Zohari, Siamak; Wilbe Ramsay, Karin; Metreveli, Giorgi; Weiss, Elisabeth; Brytting, Maria; Stivers, Marielle; Lindström, Sofia; Lundkvist, Åke; Nemirov, Kirill; Thorén, Peter; Berg, Mikael; Czifra, György; Belák, Sándor


Background: The analysis of the nonstructural (NS) gene of the highly pathogenic (HP) H5N1 avian influenza viruses (AIV) isolated in Sweden early 2006 indicated the co-circulation of two sublineages of these viruses at that time. In order to complete the information on their genetic features and relation to other HP H5N1 AIVs the seven additional genes of twelve Swedish isolates were amplified in full length, sequenced, and characterized. Results: The presence of two sub-lineages of HP H5N1 AIVs in Sweden in 2006 was further confirmed by the phylogenetic analysis of approximately the 95% of the genome of twelve isolates that were selected on the base of differences in geographic location, timing and animal species of origin. Ten of the analyzed viruses belonged to sub-clade 2.2.2. and grouped together with German and Danish isolates, while two 2.2.1. sub-clade viruses formed a cluster with isolates of Egyptian, Italian, Slovenian, and Nigerian origin. The revealed amino acid differences between the two subgroups of Swedish viruses affected the predicted antigenicity of the surface glycoproteins, haemagglutinin and neuraminidase, rather than the nucleoprotein, polymerase basic protein 2, and polymerase acidic protein, the main targets of the cellular immune responses. The distinctive characteristics between members of the two subgroups were identified and described. Conclusion: The comprehensive genetic characterization of HP H5N1 AIVs isolated in Sweden during the spring of 2006 is reported. Our data support previous findings on the coincidental spread of multiple sub-lineage H5N1 HPAIVs via migrating aquatic birds to large distance from their origin. The detection of 2.2.1. sub-clade viruses in Sweden adds further data regarding their spread in the North of Europe in 2006. The close genetic relationship of Swedish isolates sub-clade 2.2.2. to the contemporary German and Danish isolates supports the proposition of the introduction and spread of a single variant of 2.2.2. sub-clade H5N1 avian influenza viruses in the Baltic region. The presented findings underline the importance of whole genome analysis

Published in

Virology Journal
2008, volume: 5, article number: 113

Authors' information

Kiss, István
National Veterinary Institute (SVA)
Gyarmati, Peter
National Veterinary Institute (SVA)
National Veterinary Institute (SVA)
Wilbe Ramsay, Karin
Swedish University of Agricultural Sciences, Department of Biomedical Science and Veterinary Public Health
Metreveli, Giorgi
National Veterinary Institute (SVA)
Brytting, Maria
Stivers, Marielle
Lindström, Sofia
Lundkvist, Åke
Swedish Institute for Infectious Disease Control
Nemirov, Kirill
National Veterinary Institute (SVA)
Czifra, György
National Veterinary Institute (SVA)
Belák, Sándor (Belak, Sandor)
Swedish University of Agricultural Sciences, Department of Biomedical Science and Veterinary Public Health

UKÄ Subject classification

Veterinary Science
Animal and Dairy Science

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