Amino Acid Sequence Analysis of Hemagglutinin Protein of H9N2 Isolated from Broilers in Tehran in 2007

Since 1998, Iranian poultry industry has been affected by avian influenza (AI) virus, subtype H9N2. The association of high mortality and case report of H5N1 and H9N2 influenza virus in wild birds in recent years raised the suspicion of a possible new genetic modified AI virus. Partial nucleotide sequences and deduced amino acid of hemagglutinin (HA) genes of 4 H9N2 influenza viruses isolated from broilers in Iran in 2007 were genetically analyzed. The isolates possessed two types of amino acid motif -R-S-S-RlG-L- and -R-S-N-RlG-L- at the cleavage site of HA. "-R-S-N-RlG-L in Iranian isolates is the same as the motif previously reported in Israel. Glycosylation site of the virus has been missed in some isolates. Receptor binding site of the isolates were found similar to the human H9N2 isolates. Based on published reports for high similarity of H9N2 with human H5N1 isolates, it is important to consider the potential of Iranian avian influenza viruses to infect human.