Genetic analysis of hemagglutinin proteins of H3 and H1 subtypes in Kazakhstan

Abstract

The influenza is one of the most dangerous and widespread infectious diseases on the planet. A natural reservoir of the influenza A virus is wild waterfowl, which subsequently contribute to the spread of viral infection among domestic animals. Currently, different influenza A subtypes were isolated from various animal species and their genetic diversity were investigated with the subsequent possibility to predict the places of outbreaks and the transfer between species. An investigation of genetic diversity of influenza A virus is also important for a timely response by developing suitable vaccines to the emergence of new strains. In the work, we investigated two subtypes of hemagglutinin (H3, H1) from wild waterfowl in the Republic of Kazakhstan (RK). This work was aimed to determine the homology between these subtypes and currently known isolates from the NCBI database. H3N8 isolates from Kazakhstan were located in a monophyletic group together with isolates from Mongolia and Altai according to phylogenetic analysis of the hemagglutinin sequences . The hemagglutinin homology of H3N8 isolates from Kazakhstan and A/eq/Richmond/1/2007 vaccine strain was 86.07% and with A/eq/Ohio/2003 vaccine strain was 86, 24%. In the case of H1N1 isolates from Kazakhstan, the highest hemagglutinin homology was with isolates from Europe. The homology with the A/California/07/2009 (H1N1) vaccine strain was 81.27%. Important amino acids of cleavage and receptor binding sites were not variable in both H3 and H1 subtypes. The investigation of antigenic sites showed presence of variations in all five sites for H3 subtype and in 4 sites for H1.