Background: Influenza A virus is the most virulent human pathogen and causes the most serious problem. Having epidemiological knowledge about this disease is important. The aim of this study was to determine the prevalence of influenza A/H3N2 virus infection in northern Iran from 2011 to 2013 using the real-time polymerase chain reaction (RT-PCR). 

Methods: In this cross-sectional study 57 samples were collected from patients with influenza-like illness (T≥ 38 °C and cough or sore throat. Influenza-RNA was extracted from the samples using PureLink^TM Viral RNA/DNA Kit. RT-PCR was one using SuperScript III Platinum, Quantitive Real Time PCR system from invitrogen with a specific type of primers and probs. All samples were examined in the Influenza laboratory of Mazandaran University of Medical Sciences. 

Results: The mean age of patients was 38.2±14.5 year, 278 (48.69%) were males and 293 (51.31%) females. A total number of 201 patients (35.2%) were diagnosed as influenza A1 H3 N2 infection.