title: Cholera cases cluster in time and space in Matlab, Bangladesh: implications for targeted preventive interventions.
abstract: : Cholera remains a serious public health threat in Asia, Africa and in parts of the Americas. Three World health Organization (WHO) pre-qualified oral cholera vaccines are now available but their supply is limited, so current supplies must be administered strategically. This requires an improved understanding of disease transmission and control strategies.
  
  
  
  : We used demographics and disease surveillance data collected from 1991 to 2000 in Matlab, Bangladesh, to estimate the spatial and temporal extent of the zone of increased risk around cholera cases. Specifically, we compare the cholera incidence among individuals living close to cholera cases with that among individuals living close to those without medically-attended cholera in this rural endemic setting.
  
  
  
  : Those living within 50 m of a confirmed cholera case had 36 times (95% confidence interval: 23-56) the risk of becoming a cholera case in the first 3 days (after case presentation) compared with risk elsewhere in the community. The relative risk gradually declined in space and time, but remained significantly high up to 450 me away within 3 days of case presentation, and up to 150 m away within 23 days from the date of presentation of the case.
  
  
  
  : These findings suggest that, if conducted rapidly, vaccinating individuals living close to a case (ring vaccination) could be an efficient and effective strategy to target vaccine to a high-risk population in an endemic setting.
authors: Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA.
authors: Amanda K
authors: AK
authors: Debes
authors: Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA.
authors: Mohammad
authors: M
authors: Ali
authors: Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA.
authors: Andrew S
authors: AS
authors: Azman
authors: International Centre for Diarrhoeal Disease Research Bangladesh (icddr,b), Dhaka, Bangladesh.
authors: Mohammad
authors: M
authors: Yunus
authors: Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA.
authors: David A
authors: DA
authors: Sack
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001459:Bangladesh / Q000453:epidemiology; D002648:Child; D002675:Child, Preschool; D002771:Cholera / Q000453:epidemiology* / Q000517:prevention & control* / Q000635:transmission*; D022121:Cholera Vaccines / Q000627:therapeutic use*; D005260:Female; D006801:Humans; D015994:Incidence; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D008875:Middle Aged; D011159:Population Surveillance; D011634:Public Health; D012044:Regression Analysis; D012306:Risk; D062211:Spatio-Temporal Analysis; D014611:Vaccination / Q000706:statistics & numerical data*; D014734:Vibrio cholerae / Q000302:isolation & purification; D055815:Young Adult
chemical_list: D022121:Cholera Vaccines
keywords: Bangladesh; Matlab; Vibrio cholerae; cholera; cholera vaccine; disease transmission; ring vaccination