title: A rapid assessment of drinking water quality in informal settlements after a cholera outbreak in Nairobi, Kenya.
abstract: Populations living in informal settlements with inadequate water and sanitation infrastructure are at risk of epidemic disease. In 2010, we conducted 398 household surveys in two informal settlements in Nairobi, Kenya with isolated cholera cases. We tested source and household water for free chlorine residual (FCR) and Escherichia coli in approximately 200 households. International guidelines are ≥0.5 mg/L FCR at source, ≥0.2 mg/L at household, and <1 E. coli/100 mL. In these two settlements, 82% and 38% of water sources met FCR guidelines; and 7% and 8% were contaminated with E. coli, respectively. In household stored water, 82% and 35% met FCR guidelines and 11% and 32% were contaminated with E. coli, respectively. Source water FCR≥0.5 mg/L (p=0.003) and reported purchase of a household water treatment product (p=0.002) were associated with increases in likelihood that household stored water had ≥0.2 mg/L FCR, which was associated with a lower likelihood of E. coli contamination (p<0.001). These results challenge the assumption that water quality in informal settlements is universally poor and the route of disease transmission, and highlight that providing centralized water with ≥0.5 mg/L FCR or (if not feasible) household water treatment technologies reduces the risk of waterborne cholera transmission in informal settlements.
authors: Division of Foodborne, Waterborne, and Environmental Diseases, US Centers for Disease Control and Prevention, Atlanta, GA, USA.
authors: Elizabeth
authors: E
authors: Blanton
authors: Tufts University, Boston, USA and 200 College Avenue, Medford, MA 02155, USA E-mail: Natalie.Wilhelm@tufts.edu.
authors: Natalie
authors: N
authors: Wilhelm
authors: Division of Foodborne, Waterborne, and Environmental Diseases, US Centers for Disease Control and Prevention, Atlanta, GA, USA.
authors: Ciara
authors: C
authors: O'Reilly
authors: Field Epidemiology and Laboratory Training Program, Nairobi, Kenya; Ministry of Public Health & Sanitation, Nairobi, Kenya.
authors: Everline
authors: E
authors: Muhonja
authors: Field Epidemiology and Laboratory Training Program, Nairobi, Kenya; Ministry of Public Health & Sanitation, Nairobi, Kenya.
authors: Solomon
authors: S
authors: Karoki
authors: Ministry of Public Health & Sanitation, Nairobi, Kenya.
authors: Maurice
authors: M
authors: Ope
authors: Ministry of Public Health & Sanitation, Nairobi, Kenya.
authors: Daniel
authors: D
authors: Langat
authors: Field Epidemiology and Laboratory Training Program, Nairobi, Kenya; Ministry of Public Health & Sanitation, Nairobi, Kenya.
authors: Jared
authors: J
authors: Omolo
authors: Kenya Medical Research Institute, Nairobi, Kenya.
authors: Newton
authors: N
authors: Wamola
authors: Kenya Medical Research Institute, Nairobi, Kenya.
authors: Joseph
authors: J
authors: Oundo
authors: Division of Foodborne, Waterborne, and Environmental Diseases, US Centers for Disease Control and Prevention, Atlanta, GA, USA.
authors: Robert
authors: R
authors: Hoekstra
authors: Division of Foodborne, Waterborne, and Environmental Diseases, US Centers for Disease Control and Prevention, Atlanta, GA, USA.
authors: Tracy
authors: T
authors: Ayers
authors: Center for Global Health, US Centers for Disease Control and Prevention, Nairobi, Kenya.
authors: Kevin
authors: K
authors: De Cock
authors: Center for Global Health, US Centers for Disease Control and Prevention, Nairobi, Kenya; Emory Global Health Institute, Emory University, Atlanta, GA, USA and Center for Global Health, US Centers for Disease Control and Prevention, Atlanta, GA, USA.
authors: Robert
authors: R
authors: Breiman
authors: Division of Foodborne, Waterborne, and Environmental Diseases, US Centers for Disease Control and Prevention, Atlanta, GA, USA.
authors: Eric
authors: E
authors: Mintz
authors: Division of Foodborne, Waterborne, and Environmental Diseases, US Centers for Disease Control and Prevention, Atlanta, GA, USA; Tufts University, Boston, USA and 200 College Avenue, Medford, MA 02155, USA E-mail: Natalie.Wilhelm@tufts.edu.
authors: Daniele
authors: D
authors: Lantagne
mesh_terms: D002713:Chlorine; D002771:Cholera / Q000453:epidemiology / Q000517:prevention & control; D004196:Disease Outbreaks; D060766:Drinking Water / Q000382:microbiology*; D004926:Escherichia coli / Q000302:isolation & purification; D006801:Humans; D007630:Kenya; D018570:Risk Assessment; D018508:Water Purification / Q000379:methods*; D060753:Water Quality
chemical_list: D060766:Drinking Water; D002713:Chlorine