A case of chikungunya fever imported from India to Japan, follow-up of specific IgM and IgG antibodies over a 6-month period.

Chikungunya fever is an arboviral disease caused by chikungunya virus. A 37-year-old Japanese male visited India and developed fever, myalgia, rash, and persisting systemic arthralgia, the latter of which persisted for more than 2 months. The patient was diagnosed with chikungunya fever by virological and serological examinations. In the present study, we followed specific antibody responses over a 6-month period after the onset of the disease. IgM antibody was detected on days 58 and 108, but not on day 137, by enzyme-linked immunosorbent assay. Specific IgG and neutralizing antibodies were detected as late as day 192. The results indicate that specific IgM lasts for 3 to 4 months from the onset of the disease, and that IgG lasts more than 6 months.