Trends in dengue virus infection with seasonal variation at a tertiary care centre, Mangaluru: A retrospective study

: Dengue is currently the second most prevalent vector borne disease in the world. Dengue fever and its more serious forms, dengue hemorrhagic fever and dengue shock syndrome are becoming important public health problems. Since there is no immunoprophylaxis or specific antiviral therapy available, clinico-microbiological diagnosis plays a vital role in patient management and implementation of control measures. : To identify dengue seropositive patients by NS1 antigen and anti-dengue IgM antibody detection by ELISA and correlate the changes in epidemiology. A retrospective study was performed for a period of 5 years from January 2017 to December 2021 in A.J Institute of Medical Sciences & Research Centre, Mangaluru. 1871 seropositive cases of all age groups admitted in the medical wards were included. Rapid immunochromatography test and ELISA was performed to detect NS1 antigen and IgM antibodies. Platelet count and total leucocyte count were also analysed. : Out of 14656, 1871 samples (12.75%) were positive for dengue. Higher rate of cases were in males and the age group of 21 to 30 years were chiefly affected. 1158(61.89%) were positive for NS1 antigen and total positive cases for IgM antibody was 530(28.32%). About 183 (9.79%) cases were positive for both NS1 antigen and IgM antibody. An increase in the prevalence of dengue was recorded during the month of June to October. The present study indicates a decline in dengue infection from 2020 which may be attributable to preventive and control measures provided by the health care workers besides having increased awareness among people. The decline may also may be due to the outbreak of SARS –Cov-2 in December 2019, which led to under diagnosis of dengue cases.