Comparative Study of Molecular Approaches for the Detection of Influenza Virus from Patient Samples Using Real-time PCR: Prospective Disease Burden Study in Kerala (India) from 2010 to 2016.

PURPOSE OF REVIEW: Acute respiratory infections caused by influenza virus are a major cause of viral respiratory diseases globally. Surveillance of circulating subtypes and estimation of disease burden is of utmost clinical importance. Molecular surveillance and proper disease burden estimates are scarce in India although clinical influenza infections are on the rise. Our study aims to delineate the prevalent influenza subtypes in a South Indian population from cases requiring hospital visits. Using real-time polymerase chain reaction (RT-PCR), 2154 throat/nasopharyngeal swabs from patients attending Government Medical College, Thiruvananthapuram, Kerala, India, with suspected influenza-like illness, were tested for the presence of different influenza subtypes.

RESEARCH FINDINGS: Forty-three percent of specimens were positive for the influenza virus. Among these, prevalence of influenza A(H3N2), influenza B, and H1N1pdm09 was 26.7, 6.3, and 10%, respectively. Nominal co-infections were detected. An easy to use commercial kit was used for the majority of the study after proper evaluation for sensitivity and specificity against a gold standard protocol. Specific diagnosis using molecular tools caters to the urgency, and a precise measure of the disease burden and management actions are needed, especially in developing countries like India. Infection rate estimation using a sensitive RT-PCR assay signified that influenza was highly prevalent in the region. The study data generated will help understand the epidemiology of influenza in India as well as generate information for global influenza surveillance and disease burden.