Kinetics of Chikungunya Infections during an Outbreak in Southern Thailand, 2008–2009

The Indian Ocean chikungunya epidemic re-emerged in Thailand in August 2008. Forty-five adults with laboratory-confirmed chikungunya in Songkhla province, Thailand were clinically assessed and serially bled throughout the acute and convalescent phase of the disease. Patient symptoms, antibody responses, and viral kinetics were evaluated using observational assessments, polymerase chain reaction (PCR), and serological assays. All subjects experienced joint pain with 42 (93%) involving multiple joints; the interphalangeal most commonly affected in 91% of the subjects. The mean duration of joint pain was 5.8 days, 11 (25%) experiencing discomfort through the duration of the study. Rash was observed in 37 (82%) subjects a mean 3.5 days post onset of symptoms. Patents were positive by PCR for a mean of 5.9 days with sustained peak viral load through Day 5. The IgM antibodies appeared on Day 4 and peaked at Day 7 and IgG antibodies first appeared at Day 5 and rose steadily through Day 24.