title: Evaluation of pot-chlorination of wells during a cholera outbreak, Bissau, Guinea-Bissau, 2008.
abstract: We evaluated the ability of UNICEF-designed pot-chlorinators to achieve recommended free residual chlorine (FRC) levels in well water in Bissau, Guinea-Bissau, during a cholera outbreak. Thirty wells were randomly selected from six neighbourhoods. Pot-chlorinators--perforated plastic bottles filled with gravel, sand and calcium hypochlorite granules--were placed in each well. FRC was measured before and 24, 48 and 72 h after placement and compared with World Health Organization (WHO)-recommended levels of 21 mg L(-1) for well water during cholera outbreaks and 0.2-5 mg L 1 in non-outbreak settings. Presence of well covers, distance from wells to latrines, and rainfall were noted. Complete post-chlorination data were collected from 26 wells. At baseline, no wells had FRC>0.09 mg L(-1). At 24, 48 and 72 h post-chlorination, 4 (15%), 1 (4%) and 0 wells had FRC>or=1 mg L(-1) and 16 (62%), 4 (15%) and 1 (4%) wells had FRC between 0.2 and 5 mg L(-1), respectively. Several families reported discontinuing household water chlorination after wells were treated with pot-chlorinators. Pot-chlorinators failed to achieve WHO-recommended FRC levels in well water during a cholera outbreak, and conveyed a false sense of security to local residents. Pot-chlorination should be discouraged and alternative approaches to well-water disinfection promoted.
authors.affiliation: Global WASH Epidemiology Team, Waterborne Diseases Prevention Branch (WDPB), Division of Foodborne, Bacterial, and Mycotic Diseases (DBFMD), National Center for Emerging and Zoonotic Infectious Diseases (NCEZID), Centers for Disease Control and Prevention, 1600 Clifton Road, Atlanta, GA 30333, USA. ejc0@cdc.gov
authors.forename: Elizabeth C
authors.initials: EC
authors.lastname: Cavallaro
authors.forename: Julie R
authors.initials: JR
authors.lastname: Harris
authors.forename: Mauricio Serafim
authors.initials: MS
authors.lastname: da Goia
authors.forename: Jean Carlos
authors.initials: JC
authors.lastname: dos Santos Barrado
authors.forename: Aglaêr Alves
authors.initials: AA
authors.lastname: da Nóbrega
authors.forename: Inácio Carvalho
authors.initials: IC
authors.lastname: de Alvarenga de Junior
authors.forename: Augusto Paulo
authors.initials: AP
authors.lastname: Silva
authors.forename: Jeremy
authors.initials: J
authors.lastname: Sobel
authors.forename: Eric
authors.initials: E
authors.lastname: Mintz
mesh_terms: D002771:Cholera / Q000453:epidemiology / Q000517:prevention & control*; D004196:Disease Outbreaks; D006169:Guinea-Bissau / Q000453:epidemiology; D054879:Halogenation; D006801:Humans; D006863:Hydrogen-Ion Concentration; D018508:Water Purification / Q000295:instrumentation*; D014881:Water Supply / Q000592:standards*; D014944:World Health Organization