Trends in the Seroprevalence of Dengue in a Tertiary Care Hospital of North Karnataka, India

Introduction: Dengue virus of the Flaviviridae family is the causative agent of dengue fever. The Aedes aegypti mosquito is the main vector for its transmission. Though, the cases of dengue fever are mild and self-resolving, there can be fatal complications like Dengue Haemorrhagic Fever (DHF) and Dengue Shock Syndrome (DSS). Aim: To study the trends in the seroprevalence of dengue in serum samples of suspected cases. Materials and Methods: The present study was a cross- sectional study which was conducted from January 2017 to December 2019, at Belagavi Institute of Medical Sciences (BIMS), Belagavi, Karnataka, India. The serum samples were collected from suspected dengue fever cases and tested by Immunoglobulin M (IgM) capture Enzyme Linked Immunosorbent Assay (ELISA), to detect IgM antibody against dengue virus and NS1 capture ELISA for dengue NS1 (nonstructural protein 1) antigen using ELISA kits manufactured by National Institute of Virology (NIV), Pune. The tests were performed according to the manufacturer’s instruction. The data obtained from the study was analysed using descriptive statistics. Results: A total of 8,992 serum samples were tested over a period of three years, of which 1,340 (14.90%) were positive for dengue infection. Among which 1,048 (78.21%) were positive for anti-dengue IgM antibodies, 109 (8.13%) were positive for NS1 antigen and 183 (13.66%) were positive for both. Most affected age group was 11-20 years and male to female ratio is 1.18:1. The seasonal peak was observed in monsoon i.e. month of June (15.52%) followed by August (12.02%). Conclusion: Seroprevalence of dengue infection being critical signifies the importance of detection of both IgM antibodies and NS1 antigen for diagnosis of dengue infection. The study also identifies younger population being at higher risk and also monsoon as the most favourable season for viral transmission in this region and highlights the importance of concerted efforts towards disease control and prevention.