Influenza surveillance by molecular diagnosis

INTRODUCTION: Our objective was to evaluate the application of molecular techniques in the surveillance of influenza, and to describe clinical and epidemiological characteristics of cases diagnosed in 2007-2008 and 2008-2009 seasons. METHODS: We analyzed 183 pharyngeal swabs from the same number of patients referred to the virology laboratory of the Sentinel Physician Network of Castilla y Leon, the study of influenza viruses by shell-vial technique and RT-PCR capable of detecting multiple Simultaneously, influenza virus A, B, C, respiratory syncytial virus A, B and adenovirus. RESULTS: Using cell culture were isolated 17 influenza A viruses and 19 influenza B viruses (19.7% of total). By multiple RT-PCR, was detected 49 influenza A virus, 29 influenza B virus, an influenza virus C, 3 syncytial virus type A and other B and 6 adenoviruses (44.3% of total). All influenza viruses isolated in cell culture was detected by RT-PCR. RT-PCR by 5 co-infections were detected, which represented a 6.25% of co-infections on the whole of positive samples. The average age of patients was 29 years (SD = 21.07). The proportion of women and men accounted for 43.7% and 56.3% respectively. The number of cases diagnosed in relation to age follows a pattern of negative linear correlation. CONCLUSIONS: RT-PCR is revealed as an useful tool for epidemiological surveillance of influenza, allowing also to detect viral subtypes along with other viruses involved in respiratory infections.