The Virology Laboratory, NIC, NCCD, Mongolia has detected with rt-RT-PCR so far 1,126 influenza A(H1N1) pdm viruses from 3,407 specimens taking from ILI patients since October 12, 2009 when the first A(H1N1)v case has been registered in Mongolia. All rt-RT-PCR(+) samples were inoculated into MDCK cell culture and isolated 194 A(H1N1)pdm viruses. The 4th segment of the genome or HA gene (1.701 nucleotides) have been sequenced fully in the Virology Laboratory, NIC, NCCD, Mongolia of three representative strains designated as: A/Ulaanbaatar/5882/2009(H1N1), A/Ulaanbaatar/6133/2009(H1N1) and A/Ulaanbaatar/6266/2009(H1N1), and the sequences were deposited with the accession numbers of CY050844.1, CY050845.1 and CY050846.1 in the GenBank.

The HA genes of the influenza virus strains isolated in Mongolia have had nucleotide differences from the consensus A(H1N1)v strain in 7-9 positions and have been similar with the recent strains circulating in Japan and China. The studies of the antigenic and genetic characteristics of the Mongolian strains are continuing.