title: An Outbreak of Chikungunya in Rural Bangladesh, 2011.
abstract: 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.
  
  
  METHODS
  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 clinical 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 randomly 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% had ≥3. 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.
  
  
  CONCLUSIONS
  The evidence suggests that this outbreak was due to Chikungunya. The high attack rate suggests that the infection was new to this area, and the increased risk among adult women suggests that risk of transmission may have been higher around households. Chikungunya is an emerging infection in Bangladesh and current surveillance and prevention strategies are insufficient to mount an effective public health response.
authors.affiliation: Epidemiology Department, Institute of Epidemiology Disease Control and Research, Dhaka, Bangladesh.
authors.forename: Selina
authors.initials: S
authors.lastname: Khatun
authors.affiliation: Epidemiology Department, Institute of Epidemiology Disease Control and Research, Dhaka, Bangladesh.
authors.forename: Apurba
authors.initials: A
authors.lastname: Chakraborty
authors.affiliation: Institute of Epidemiology Disease Control and Research, Dhaka, Bangladesh.
authors.forename: Mahmudur
authors.initials: M
authors.lastname: Rahman
authors.affiliation: Epidemiology Department, Institute of Epidemiology Disease Control and Research, Dhaka, Bangladesh.
authors.forename: Nuzhat
authors.initials: N
authors.lastname: Nasreen Banu
authors.affiliation: Epidemiology Department, Institute of Epidemiology Disease Control and Research, Dhaka, Bangladesh.
authors.forename: Mohammad Mostafizur
authors.initials: MM
authors.lastname: Rahman
authors.affiliation: Department of Outbreak and Surveillance Research, Centre for Communicable Diseases, International Centre for Diarrhoeal Disease Research (icddr,b), Dhaka, Bangladesh.
authors.forename: S M Murshid
authors.initials: SM
authors.lastname: Hasan
authors.affiliation: Department of Infectious Diseases, Stanford University, Stanford, California, United States of America.
authors.forename: Stephen P
authors.initials: SP
authors.lastname: Luby
authors.affiliation: Department of Outbreak and Surveillance Research, Centre for Communicable Diseases, International Centre for Diarrhoeal Disease Research (icddr,b), Dhaka, Bangladesh.
authors.forename: Emily S
authors.initials: ES
authors.lastname: Gurley
mesh_terms: D000293:Adolescent; D000328:Adult; D000330:Aedes / Q000821:virology; D017677:Age Distribution; D000368:Aged; D000818:Animals; D000914:Antibodies, Viral / Q000097:blood; D001459:Bangladesh / Q000453:epidemiology; D065632:Chikungunya Fever / Q000097:blood / Q000453:epidemiology* / Q000635:transmission / Q000821:virology; D002646:Chikungunya virus / Q000502:physiology*; D002648:Child; D004196:Disease Outbreaks; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D055815:Young Adult
chemical_list: D000914:Antibodies, Viral