Seroprevalence of chikungunya virus infection in East Delhi over a decade: A retrospective study

Chikungunya fever is an arboviral disease and remains a major public health concern in India ever since its first emergence in 1963 in Kolkata. Delhi has witnessed several outbreaks over the years. This retrospective study was performed to examine the epidemiological dynamics on all clinically suspected Chikungunya cases tested by ELISA for anti-CHIK virus IgM antibodies from 2010 to 2020 at a tertiary care hospital in Delhi. Archived data of suspected patients screened for CHIKV IgM by ELISA were retrieved for the period 2010-2020. Epidemiological data was used in the study. GIS mapping was done for the positive cases. Among the 445 samples tested, 57.3% were positive with the greatest number of cases (76.5%) in 2016 and significantly higher number of cases in monsoon & post-monsoon periods (<i>p</i> < 0.005). Seropositivity was highest in patients aged 45-54 years (69.6%); however, the disease did not show predilection for a specific gender. GIS mapping showed the burden of Chikungunya infection was concentrated in a 5-10 km radius from the study site with significant presence of cross-border cases. Our study indicates a geographically concentrated burden of Chikungunya in East and South East Delhi with ebbs and flow over time in the past decade. In view of non-availability of any licensed vaccine for this disease, surveillance of active cases, vector management and mapping of disease may help in prevention strategies.