Influenza A (H3N2) Outbreak, Nepal
Figure 2. . Unrooted phylogenetic analysis of HA1 hemagglutinin nucleotide sequences from 26 Nepal isolates and H3N2 vaccine and reference strains. The Nepal isolates have drifted from the 2004–2005 A/Fujian/411/03 vaccine strain (and A/Wyoming/03/03 vaccine seed strain) and are genetically equivalent to A/California/7/04, the 2005–2006 Northern Hemisphere vaccine strain. A K145N substitution (branch point indicated by the arrow) was observed in 24 of 26 Nepal isolates and represents a genetic marker for the dominant lineage of H3N2 viruses during the 2004–2005 season. Nucleotide and amino acid sequences for all Nepal isolates are available from GenBank under accession no. AY945263–AY945288. The asterisk indicates isolates from Table 2 that were antigenically distinct from A/Wyoming/303.