Fax +41 61 306 12 34 E-Mail karger@karger.ch www.karger.com Short Communication Intervirology 2009;52:63–67 DOI: 10.1159/000214634 Molecular Analysis of Human Influenza Virus in Tehran, Iran Z. Soltani a, b M. Hosseini b M. Shahidi a M. Hedayati c M.T. Kheiri a a Influenza Unit, Pasteur Institute of Iran, b Department of Microbiology, Faculty of Biological Sciences, Shahid-Beheshti University, Tehran, Iran; c Department of Biochemistry and Molecular Biology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Md., USA Introduction Human influenza viruses continually circulate and cause yearly epidemics. Novel strains emerge sporadical- ly as pandemic viruses [1, 2]. The surface hemagglutinin (HA) glycoprotein of influenza viruses is the major target for neutralizing antibodies, and point mutations in the potential antigenic domains of this protein are thought to allow viruses to evade established immune antibodies in the human population. Analyses of epidemic influenza virus isolates, therefore, have chiefly focused on antigen- ic characterization of the HA glycoprotein in order to de- tect new variants of each epidemic strain for the recom- mendation of vaccine strains in each season [3, 4]. An- nual epidemics are caused by the rapid evolution of the viral genome. Such changes can be monitored through antigenetic analysis and gene sequencing, particularly the gene that codes for viral HA. There are a few reports of human influenza viruses from Iran, a seroepidemiological description published in 2004 [5] and a more recent molecular and phylogenet- ic analysis in Shiraz [6] . Here, we collected a sample of human influenza viruses in Tehran during the 2006– 2007 influenza seasons. We used molecular techniques to determine the typing and subtyping of human influenza virus on these samples. The data obtained were then compared to the vaccine strains that were recommended by the WHO for the same period. Key Words A/H1N1  A/H3N2  Hemagglutinin gene  Influenza virus, Tehran  Phylogenetic analysis Abstract Background: To date there are no reports of molecular and phylogenetic analyses of human influenza virus in Tehran, Iran. Objectives: We isolated and characterized circulating influenza viruses in a sample of patients in Tehran. Methods: Nasal and pharyngeal swabs were collected from 57 indi- viduals who were suspected of having influenza between October 2005 and January 2007. These samples were cul- tured and subsequently genotyped by RT-PCR and sequenc- ing analyses. Results: Twelve of 57 samples (21%) were posi- tive for human influenza virus. Out of the 12 positive samples, 7 were A/H3N2 (58%), 3 were A/H1N1 (25%) and 2 were B subtypes (17%). The phylogenetic analysis of the hemagglu- tinin gene showed that the H1N1 isolates were close to the A/New Caledonia/20/99 and the H3N2 isolates were close to the A/Panama/2007/99 and A/Moscow/10/99 vaccine strains. Conclusion: In a sample of clinical patients in Tehran, Iran, the predominant subtype of human influenza virus was de- termined to be A/H3N2, followed by A/H1N1 and B. In addi- tion, phylogenetic analysis on H1 showed some genetic drifts from vaccine strains, but the phylogeny of H3 demon- strated that these isolates were from the previous vaccine strains. Copyright © 2009 S. Karger AG, Basel Received: September 30, 2008 Accepted: February 10, 2009 Published online: April 25, 2009 Masoumeh Tavasoti Kheiri, PhD Influenza Unit, Institute Pasteur of Iran 12 Farvardin St. Tehran (Iran) Tel. +98 21 6695 3311, Fax +98 21 6640 9467, E-Mail mtkheiri@pasteur.ac.ir © 2009 S. Karger AG, Basel 0300–5526/09/0522–0063$26.00/0 Accessible online at: www.karger.com/int