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Genetic diversity of the 2009 pandemic influenza A(H1N1) viruses in Finland.

Ikonen N, Haanpää M, Rönkkö E, Lyytikäinen O, Kuusi M, Ruutu P, Kallio-Kokko H, Mannonen L, Lappalainen M, Ziegler T, Julkunen I - PLoS ONE (2010)

Bottom Line: During the next three months almost all infections were found from patients who had recently traveled abroad.Most amino acid changes in HA and NA molecules accumulated on the surface of the molecule and were partly located in antigenic sites.All Finnish pandemic viruses were sensitive to oseltamivir having the amino acid histidine at residue 275 of the neuraminidase molecule.

View Article: PubMed Central - PubMed

Affiliation: Viral Infections Unit, Department of Vaccination and Immune Protection, National Institute for Health and Welfare THL, Helsinki, Finland. niina.ikonen@thl.fi

ABSTRACT

Background: In Finland, the first infections caused by the 2009 pandemic influenza A(H1N1) virus were identified on May 10. During the next three months almost all infections were found from patients who had recently traveled abroad. In September 2009 the pandemic virus started to spread in the general population, leading to localized outbreaks and peak epidemic activity was reached during weeks 43-48.

Methods/results: The nucleotide sequences of the hemagglutinin (HA) and neuraminidase (NA) genes from viruses collected from 138 patients were determined. The analyzed viruses represented mild and severe infections and different geographic regions and time periods. Based on HA and NA gene sequences, the Finnish pandemic viruses clustered in four groups. Finnish epidemic viruses and A/California/07/2009 vaccine virus strain varied from 2-8 and 0-5 amino acids in HA and NA molecules, respectively, giving a respective maximal evolution speed of 1.4% and 1.1%. Most amino acid changes in HA and NA molecules accumulated on the surface of the molecule and were partly located in antigenic sites. Three severe infections were detected with a mutation at HA residue 222, in two viruses with a change D222G, and in one virus D222Y. Also viruses with change D222E were identified. All Finnish pandemic viruses were sensitive to oseltamivir having the amino acid histidine at residue 275 of the neuraminidase molecule.

Conclusions: The Finnish pandemic viruses were quite closely related to A/California/07/2009 vaccine virus. Neither in the HA nor in the NA were changes identified that may lead to the selection of a virus with increased epidemic potential or exceptionally high virulence. Continued laboratory-based surveillance of the 2009 pandemic influenza A(H1N1) is important in order to rapidly identify drug resistant viruses and/or virus variants with potential ability to cause severe forms of infection and an ability to circumvent vaccine-induced immunity.

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Related in: MedlinePlus

Amino acid differences in the NA between the Finnish pandemic viruses and the A/California/07/2009.The amino acid differences are located in the tetrameric NA structure. Amino acid changes in antigenic sites are colored in pink and changes in other regions in yellow. The catalytic site is marked in purple. Changes in antigenic sites are illustrated by the amino acid residue number, the amino acids that have changed, and in addition, the number of viruses found with this change is indicated (numbers in red denote severe cases). The structure is based on the 3-dimensional NA structure of A/Brevig Mission/1/1918 (RCSB Protein Bank accession number 3beq) virus.
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pone-0013329-g005: Amino acid differences in the NA between the Finnish pandemic viruses and the A/California/07/2009.The amino acid differences are located in the tetrameric NA structure. Amino acid changes in antigenic sites are colored in pink and changes in other regions in yellow. The catalytic site is marked in purple. Changes in antigenic sites are illustrated by the amino acid residue number, the amino acids that have changed, and in addition, the number of viruses found with this change is indicated (numbers in red denote severe cases). The structure is based on the 3-dimensional NA structure of A/Brevig Mission/1/1918 (RCSB Protein Bank accession number 3beq) virus.

Mentions: In Figure 5, amino acid changes between the Finnish viruses and the vaccine viruses are shown in a three-dimensional model of the NA molecule. As in the HA, most amino acid changes were located on the surface of the NA molecule and these changes cover a considerable surface area of the molecule. Only three changes were found in antigenic sites [8].


Genetic diversity of the 2009 pandemic influenza A(H1N1) viruses in Finland.

Ikonen N, Haanpää M, Rönkkö E, Lyytikäinen O, Kuusi M, Ruutu P, Kallio-Kokko H, Mannonen L, Lappalainen M, Ziegler T, Julkunen I - PLoS ONE (2010)

Amino acid differences in the NA between the Finnish pandemic viruses and the A/California/07/2009.The amino acid differences are located in the tetrameric NA structure. Amino acid changes in antigenic sites are colored in pink and changes in other regions in yellow. The catalytic site is marked in purple. Changes in antigenic sites are illustrated by the amino acid residue number, the amino acids that have changed, and in addition, the number of viruses found with this change is indicated (numbers in red denote severe cases). The structure is based on the 3-dimensional NA structure of A/Brevig Mission/1/1918 (RCSB Protein Bank accession number 3beq) virus.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2958116&req=5

pone-0013329-g005: Amino acid differences in the NA between the Finnish pandemic viruses and the A/California/07/2009.The amino acid differences are located in the tetrameric NA structure. Amino acid changes in antigenic sites are colored in pink and changes in other regions in yellow. The catalytic site is marked in purple. Changes in antigenic sites are illustrated by the amino acid residue number, the amino acids that have changed, and in addition, the number of viruses found with this change is indicated (numbers in red denote severe cases). The structure is based on the 3-dimensional NA structure of A/Brevig Mission/1/1918 (RCSB Protein Bank accession number 3beq) virus.
Mentions: In Figure 5, amino acid changes between the Finnish viruses and the vaccine viruses are shown in a three-dimensional model of the NA molecule. As in the HA, most amino acid changes were located on the surface of the NA molecule and these changes cover a considerable surface area of the molecule. Only three changes were found in antigenic sites [8].

Bottom Line: During the next three months almost all infections were found from patients who had recently traveled abroad.Most amino acid changes in HA and NA molecules accumulated on the surface of the molecule and were partly located in antigenic sites.All Finnish pandemic viruses were sensitive to oseltamivir having the amino acid histidine at residue 275 of the neuraminidase molecule.

View Article: PubMed Central - PubMed

Affiliation: Viral Infections Unit, Department of Vaccination and Immune Protection, National Institute for Health and Welfare THL, Helsinki, Finland. niina.ikonen@thl.fi

ABSTRACT

Background: In Finland, the first infections caused by the 2009 pandemic influenza A(H1N1) virus were identified on May 10. During the next three months almost all infections were found from patients who had recently traveled abroad. In September 2009 the pandemic virus started to spread in the general population, leading to localized outbreaks and peak epidemic activity was reached during weeks 43-48.

Methods/results: The nucleotide sequences of the hemagglutinin (HA) and neuraminidase (NA) genes from viruses collected from 138 patients were determined. The analyzed viruses represented mild and severe infections and different geographic regions and time periods. Based on HA and NA gene sequences, the Finnish pandemic viruses clustered in four groups. Finnish epidemic viruses and A/California/07/2009 vaccine virus strain varied from 2-8 and 0-5 amino acids in HA and NA molecules, respectively, giving a respective maximal evolution speed of 1.4% and 1.1%. Most amino acid changes in HA and NA molecules accumulated on the surface of the molecule and were partly located in antigenic sites. Three severe infections were detected with a mutation at HA residue 222, in two viruses with a change D222G, and in one virus D222Y. Also viruses with change D222E were identified. All Finnish pandemic viruses were sensitive to oseltamivir having the amino acid histidine at residue 275 of the neuraminidase molecule.

Conclusions: The Finnish pandemic viruses were quite closely related to A/California/07/2009 vaccine virus. Neither in the HA nor in the NA were changes identified that may lead to the selection of a virus with increased epidemic potential or exceptionally high virulence. Continued laboratory-based surveillance of the 2009 pandemic influenza A(H1N1) is important in order to rapidly identify drug resistant viruses and/or virus variants with potential ability to cause severe forms of infection and an ability to circumvent vaccine-induced immunity.

Show MeSH
Related in: MedlinePlus