Prevalence of Chikungunya and Scrub Typhus Coinfection among Dengue Negative Patients in Kolkata, India-A Newly Emerging Public Health Hazard

The chikungunya virus (CHIKV) and scrub typhus infection has scattered worldwide creating human health hazards in India and Asia specific region. We aimed to identify chikungunya, scrub typhus, and their co-infection in dengue-negative samples having undifferentiated febrile illnesses. Enzyme linked immunosorbent assay (ELISA) methods were used to detect the chikungunya and scrub typhus specific IgM antibody by using chikungunya IgM capture ELISA kit and scrub typhus IgM Microlisa ELISA kit, respectively. OD value was measured with the help of BeneSphera (India) ELISA microplate reader. Among 490 suspected patients, 57 (11.63%) samples were tested positive for chikungunya IgM antibodies, while 43 (8.77%) came positive for scrub typhus IgM antibodies, but all samples tested negative for dengue IgM antibodies. Additionally, 5% of the total positive cases were positive for both chikungunya and scrub typhus infection. Our study offers a hypothesis regarding one of the possible causes of the decline in the frequency of scrub typhus and chikungunya cases reported in Kolkata and other districts of West Bengal. As an outcome, physicians treating undifferentiated febrile patients in endemic locations should look for chikungunya, scrub typhus, and existing coinfection between them to avoid delayed diagnosis and provide proper treatment against these infections.