Household based treatment of drinking water with flocculant-disinfectant for preventing diarrhoea in areas with turbid source water in rural western Kenya: cluster randomised controlled trialBMJ 2005; 331 doi: https://doi.org/10.1136/bmj.38512.618681.E0 (Published 01 September 2005) Cite this as: BMJ 2005;331:478
- John A Crump, medical epidemiologist ()1,
- Peter O Otieno, study coordinator2,
- Laurence Slutsker, director2,
- Bruce H Keswick, scientist3,
- Daniel H Rosen, statistician2,
- R Michael Hoekstra, statistician4,
- John M Vulule, director5,
- Stephen P Luby, medical epidemiologist1
- 1 Foodborne and Diarrhoeal Diseases Branch, Division of Bacterial and Mycotic Diseases, National Center for Infectious Diseases, Centers for Disease Control and Prevention, 1600 Clifton Road, MS A-38, Atlanta, Georgia 30333, USA
- 2 Centers for Disease Control and Prevention, PO Box 1578, Kisumu, Kenya
- 3 Procter & Gamble Health Sciences Institute, 8700 Mason Montgomery Road, Mason, Ohio 45040, USA
- 4 Biostatistics and Informatics Branch, Division of Bacterial and Mycotic Diseases, National Center for Infectious Diseases, Centers for Disease Control and Prevention, Georgia
- 5 Center for Vector Biology Control and Research, Kenya Medical Research Institute, PO Box 1578, Kisumu, Kenya
- Correspondence to: J A Crump
- Accepted 26 May 2005
Objective To compare the effect on prevalence of diarrhoea and mortality of household based treatment of drinking water with flocculant-disinfectant, sodium hypochlorite, and standard practices in areas with turbid water source in Africa.
Design Cluster randomised controlled trial over 20 weeks.
Setting Family compounds, each containing several houses, in rural western Kenya.
Participants 6650 people in 605 family compounds.
Intervention Water treatment: flocculant-disinfectant, sodium hypochlorite, and usual practice (control).
Main outcome measures Prevalence of diarrhoea and all cause mortality. Escherichia coli concentration, free residual chlorine concentration, and turbidity in household drinking water as surrogates for effectiveness of water treatment.
Results In children < 2 years old, compared with those in the control compounds, the absolute difference in prevalence of diarrhoea was –25% in the flocculant-disinfectant arm (95% confidence interval –40 to –5) and –17% in the sodium hypochlorite arm (–34 to 4). In all age groups compared with control, the absolute difference in prevalence was –19% in the flocculant-disinfectant arm (–34 to –2) and –26% in the sodium hypochlorite arm (–39 to –9). There were significantly fewer deaths in the intervention compounds than in the control compounds (relative risk of death 0.58, P = 0.036). Fourteen per cent of water samples from control compounds had E coli concentrations < 1 CFU/100 ml compared with 82% in flocculant-disinfectant and 78% in sodium hypochlorite compounds. The mean turbidity of drinking water was 8 nephelometric turbidity units (NTU) in flocculant-disinfectant households, compared with 55 NTU in the two other compounds (P < 0.001).
Conclusions In areas of turbid water, flocculant-disinfectant was associated with a significant reduction in diarrhoea among children < 2 years. This health benefit, combined with a significant reduction in turbidity, suggests that the flocculant-disinfectant is well suited to areas with highly contaminated and turbid water.
This study was supported by a cooperative research and development agreement between the Centers for Disease Control and Prevention and Procter & Gamble. The data were presented in part at the International Conference on Emerging Infectious Diseases, Atlanta, GA, 29 February 2004. We thank the director of KEMRI for permission to publish this work. We thank the study team: Jeremiah K Khumwa (laboratory technologist); Aston A Atemo (Asembo site supervisor); Jeniphe A Ochieng', Samwel O Akoko, Vincent O Onoka, Helida A Orwa, Jacinta A Otieno, Fredrick O Rairo, Maurice O Sadia, Fredrick H Watanga (Asembo field workers and sample collectors); Rosemary A Ochiewo (Gem site supervisor); Fredrick A Ayayo, Dorcas A Ogongo, Nicholas C O Oketch, Susan A Oluoch, Raphael O Otiato, George O Otwoma, Barack O Owiti, Lillian A Sewe (Gem field workers and sample collectors); Monica A Nyaburi (data entry clerk); and James Kwach (data manager). We also thank Sabina Dunton and Lucy Nyasoko for administrative support; Kimberly A Lindblade, Kubage Adazu, and Frank Odhiambo for invaluable assistance and advice on community issues and logistics; and Maurice Ombok for global information systems expertise. Contributors: SPL and JAC were responsible for study concept and design. JAC, POO, DHR, and LS gathered the data, JAC, SPL, RMH, and DHR carried out the analysis, and JAC, SPL, POO, LS, RMH, and DHR interpreted the data. JAC, SPL, POO, LS, BHK, DHR, RMH revised the manuscript. JAC, SPL, and BHK obtained funding. JAC, SPL, DHR, LS, and JMV provided administrative, technical, or material support. JAC and SPL supervised the study. JAC drafted the manuscript and is guarantor.
Funding JAC, SPL, and POO received research support from Procter & Gamble.
Competing interests BHK is employed by Procter & Gamble. He critically reviewed the study protocol, made some technical suggestions, arranged for the delivery to Kenya of flocculant-disinfectant sachets, and assisted with the delivery of other supplies. Procter & Gamble employees were not involved in data collection or analysis. They commented on the interpretation of the analysis after oral presentation of the results and in response to drafts of the manuscript. The Centers for Disease Control and Prevention retained the right to publish results without approval from Procter & Gamble.
Ethical approval An institutional review board at CDC and the scientific steering committee and ethical review committee of KEMRI reviewed and approved the study protocol.
- Accepted 26 May 2005