Tehran University of Medical Sciences Iranian Journal of Public Health 2251-6085 36 3 2007 09 15 1 7  T Mokhtari-Azad F Rezaie-Khollari AR Nadji V Salimi Z Noroozbabaie M Naseri AR Mirzaie Z Saadatmand   MM Gouya AR Esteghamati   R Hamkar 2015 10 03 Background: Influenza A viruses bearing all known HA and NA subtypes have been isolated from avian hosts: but only the A/H1N1,A/H2N2 and A/H3N2 influenza subtypes have been associated with widespread epidemics in humans un­til now .While influenza B detected only in humans. Subtype H5 infection in humans occurred for the first time dur­ing 1997-1998 in Hong Kong, then China in 2003, Vietnam and Thailand in 2004 and continued to 2005-2006 in Tur­key and Egypt. In this study a Multiplex Nested RT-PCR was developed for simultaneous detection of influenza virus A and B in clinical samples. Methods: Throat swab and throat wash was collected between October 2005 and September 2006 from 689 patients with a suspected influenza virus infection. Samples were transported to the National Influenza Center (Tehran Univer­sity of Medical Science, School of Public Health). Each sample is divided into two parts in order to virus isolation and nested RT-PCR. Results: The RT-PCR detected in 75 cases of influenza A and B, compared to 26 cases by virus isolation and 74 cases are positive by RT-PCR. In total, 50 out of 74 RT-PCR positive specimens were negative by virus isolation. The RT-PCR provides a sensitive and specific method for detecting and typing influenza viruses A and B. Conclusion: The RT-PCR provides a sensitive and specific method for detecting and typing influenza viruses A and B. Multi­plex RT-PCR can also be used to accurately detect more than one viral template in the same reaction mixture, allow­ing viral confections to be identified with the same respiratory specimen. https://ijph.tums.ac.ir/index.php/ijph/article/view/2098 https://ijph.tums.ac.ir/index.php/ijph/article/download/2098/2079