Seroprevalence and clinical manifestations of chikungunya virus infection in rural areas of Chandrapur, Maharashtra, India.

BACKGROUND & OBJECTIVES Chikungunya virus (CHIKV) infection has recently witnessed re-emergence, affecting rural areas of India with high morbidity rates. This prospective study was conducted to evaluate seroprevalence and clinical manifestation in targeted villages reporting cases of CHIKV infection. METHODS A total of 482 patients were recruited from Kalmana and Kothari villages of Ballarpur; Chandrapur district of Maharashtra state, India during CHIKV outbreaks in 2011-12. The serum samples from infected CHIKV patients were simultaneously screened through ELISA for detection of antigen and antibodies (IgM and IgG). Chi-square analysis was used to evaluate differences in seropositivity between age, gender and clinical manifestations of CHIKV. RESULTS Out of 482 enrolled participants, 197 (41%) males and 285 (59%) females were aged between 5 and 92 yr. The clinical manifestations such as small joint pain (80%), neck stiffness (75%), fever (49%) and large joint pain (47%) were observed amongst CHIKV infected subjects. Mucocutaneous rashes (91%) on knees (71%), feet (56%), fingers and palms (54%) were also observed. Overall, seroprevalence of CHIKV infection was found to be 46% in infected participants during the epidemic period. Among risk factors, ageing and female gender was strongly associated with a raised seroprevalence of CHIKV infection along with symptoms such as rashes, small joints pain and neck stiffness. INTERPRETATION & CONCLUSION This study reported high seroprevalence rates of CHIKV infection in targeted popula- tions, suggesting its re-emergence in rural India. Proper surveillance is, therefore, necessary to minimize re-emergence and in controlling these impending and sporadic outbreaks.