Epidemiology of chikungunya based on laboratory surveillance data—India, 2016–2018

BACKGROUND: We analysed the laboratory surveillance data generated by the network of virology laboratories from January 2016 to July 2018 to describe the epidemiology of chikungunya in India. METHODS: Suspected patients reporting to virology laboratories are investigated for the presence of immunoglobulin M (IgM) antibodies against chikungunya virus (CHIKV) as evidence of recent infection. We analysed the data to describe the distribution of seropositive individuals by time, place and demographic characteristics. RESULTS: Of the 49 380 sera tested from suspected patients, 20.5% were seropositive. CHIKV IgM positivity was seen throughout the year, with a peak between September and December. The laboratories diagnosed 28 outbreaks of chikungunya during the study period. CONCLUSIONS: Laboratory surveillance data indicate continued transmission of CHIKV in many regions of India.