Burden of Chikungunya and its seasonal trend in south Karnataka- A study in a tertiary care centre

Introduction: Mosquito borne arboviral infections have become major public health problem at present due to many emerging and re – emerging infections and Chikungunya is one of them. Although Chikungunya causes severe clinical manifestations like arthritis, it is not routinely tested at the health care facilities and therefore goes undiagnosed and as such its prevalence is likely to be underestimated. Climate is one of the important factor influencing the occurrence and distribution of disease. Objectives: a) To estimate seroprevalence of Chikungunya virus infection among clinically suspected cases. b) To determine the seasonal variation of Chikungunya infection. Materials and Methods: A cross sectional study was conducted at a tertiary care hospital using secondary data maintained in the microbiology laboratory registers, for clinically suspected patients of Chikungunya infection who reported to the hospital from January- December 2017. Prevalence was estimated by analyzing data for the results of IgM antibody by ELISA tests and any variations in disease reporting by age, gender and season were assessed. Statistical analysis was done using WHO Epi info software version 3.5.4. Results: A total of 1308 serum samples were analyzed during the study period. Out of which 123 (9.4%) samples were found positive for Chikungunya infection by IgM ELISA. The proportion of Chikungunya cases was higher in monsoon season with maximum rate of positivity in the month of July 48 (39.02%). Age group of 16-30 years was the most commonly affected i.e. (35.77%). Conclusion: The present study confirms that Chikungunya is mainly a disease of rainy season and also identifies certain vulnerable groups for effective planning of interventions. Keywords: Chikungunya, Immunoglobulin M, Seasonal variation, Seroprevalence.