Relative Frequency of Seasonal Influenza A and B in Khuzestan Province by Reverse Transcription-Polymerase Chain Reaction (RT-PCR) During 2009-2010

Background: Influenza A and B viruses are the major causative agents of human respiratory infections, and these viruses are responsible for considerable mortality and morbidity around the world. Objectives: The objective of this study was to determine the frequency of influenza among suspected patients with influenza-like syndrome by RT- PCR assay in Khuzestan province of Iran during 2009-2010. Patients and Methods: Nasopharyngeal swabs were collected from 655 suspected patients with influenza-like syndrome in Khuzestan province Iran from March 2009 to February 2010. Clinical samples were taken within the 48 hours of initial symptoms, and were stored at -70 ? C. The patients were between 1 month and 85 years old. Initially all samples were tested for Influenza A and B viruses. Subsequently, for those samples with positive results for influenza A virus, influenza A/H3N2, and A/H1N1 tests were performed. The total assays were performed using RT-PCR. Result: Of 655 samples, 69 (10.53%) had positive results for human influenza A virus, and 5 (0.7%) samples had positive results for influenza B. Of those 69 samples with positive results for influenza A viruses, 45 (6.8%) were H3N2, and 24 (3.6%) were H1N1 subtypes. In this study most cases with positive results were less than 20 years. The sample positive included 49% males and 51% females. The peak seasonal influenza was between October and December 2009. Conclusions: This finding showed that the predominant subtype of influenza virus among patients is A/H3N2, followed by A/H1N1 and B in Khuzestan province during the 2009-2010.