11 Influenza surveillance in the Islamic.pmd

1Department of Virology, School of Public Health and Institute of Public Health Research, Tehran University of Medical Sciences, Tehran, Islamic Republic of Iran. Received: 14/11/2001; accepted 27/06/2002 ABSTRACT To better understand the annual distribution of influenza virus in our country, we isolated and typed 45 viruses from 1043 patients with acute respiratory illnesses in a 10-year study conducted by the National Influenza Centre of the Islamic Republic of Iran The seasonal distribution of influenza typically ran from November to April. Type A influenza was most common during the winters of 1991–92, 1997–98 and 2000–01 and type B influenza was most common during 1992–5 and 1996–97. Both type A and type B viruses circulated in 1995–96 and 1998–2000. A serological survey based on haemagglutination inhibition test confirmed our findings. The annual pattern of strains isolated was similar to the worldwide pattern during the same interval.