Aim: Isolation and study of molecular genetic characteristics of pandemic influenza virus A (H1N1) circulated in Amur region in autumn 2009 as well as testing of serum samples taken from citizens of this region during November- December 2009 in order to measure levels of antibodies to socially significant serotypes of influenza A virus.
Materials and methods: Strain of pandemic influenza virus A/Blagoveschensk/01/2009 (H1N1) was isolated on MDCK cell culture and nucleotide sequences of all eight segments of viral genome were determined. Five hundred seventy-six serum samples taken in Amur region in autumn 2009 were tested by hemagglutination inhibition assay.
Results: Nucleotide sequence of A/Blagovechensk/01/2009 (H1N1) strain was 99.7% identical to reference influenza virus strain A/California/04/2009. Diagnostically significant titers of antibodies to pandemic influenza virus were observed in 46.3% of persons younger 30 years old and in 20.1% older persons. Antibodies to seasonal influenza virus H1N1 and H3N2 were detected in 39.5 and 29.8% of persons respectively.
Conclusion: Final seroepidemiological picture of distribution of pandemic virus in Amur region matches with the one for seasonal influenza virus A (H1N1): > 60% of seropositive persons were registered in age group < 18 years old, and this proportion increases with increasing age.