Persistence of antibody response in chikungunya

Chikungunya is a mosquito-borne viral illness associated with chronic arthritic symptoms that persist for months. The IgM antibody appears within a week post any infection and declines at 2-3 months. The present study was aimed to demonstrate the presence of specific IgM antibody among chikungunya confirmed cases. Blood samples were collected from chikungunya PCR positive patients at the time of diagnosis, at 1-week, 1, 8, 10 and 12 months post infection. All acute and follow-up serum samples were evaluated for chikungunya virus-specific IgM antibodies using ELISA technique. Our findings indicate the persistence of anti-chikungunya IgM up to 10-months post-infection in a majority of chikungunya virus infected persons. Interpretation of results should be carefully done as only IgM ELISA is used to diagnose acute infection, especially post chikungunya outbreak. The presence of IgM antibody does not rule out the absence of any other diagnosis due to its persistence. Thus, we hypothesize that real-time PCR is more reliable for the detection of acute chikungunya cases in endemic areas while IgM detection may be useful in identifying exposure to this disease.