RESEARCH ARTICLE An Outbreak of Chikungunya in Rural

Background The first identified Chikungunya outbreak occurred in Bangladesh in 2008. In late October 2011, a local health official from Dohar Sub-district, Dhaka District, reported an outbreak of undiagnosed fever and joint pain. We investigated the outbreak to confirm the etiology, describe the clinical presentation, and identify associated vectors. Methodology During November 2–21, 2011, we conducted house-to-house surveys to identify suspected cases, defined as any inhabitant of Char Kushai village with fever followed by joint pain in the extremities with onset since August 15, 2011. We collected blood specimens and clini-cal histories from self-selected suspected cases using a structured questionnaire. Blood samples were tested for IgM antibodies against Chikungunya virus. The village was divided into nine segments and we collected mosquito larvae from water containers in seven ran-domly selected houses in each segment. We calculated the Breteau index for the village and identified the mosquito species. Results The attack rate was 29 % (1105/3840) and 29 % of households surveyed had at least one suspected case: 15 % had3. The attack rate was 38 % (606/1589) in adult women and 25 % in adult men (320/1287). Among the 1105 suspected case-patients, 245 self-selected for testing and 80 % of those (196/245) had IgM antibodies. In addition to fever and joint pain, 76 % (148/196) of confirmed cases had rash and 38%(75/196) had long-lasting joint pain. The village Breteau index was 35 per 100 and 89%(449/504) of hatched mosquitoes were Aedes albopictus