International network to promote household water treatment and safe storage.

On February 25, 2003, more than 30 representatives from United Nations agencies, international nongovernmental organizations, research institutions, professional associations, and private companies met in Geneva, Switzerland, to establish the International Network to Promote Household Water Treatment and Safe Storage, sponsored by the World Health Organization (WHO). The group has since convened at the Kyoto World Water Forum, Kyoto, Japan, in Washington, D.C., and in Cape Town, South Africa. At the next plenary meeting, in Nairobi, Kenya, on June 14-15, 2004, participants will consider a 5-year strategic plan to reduce waterborne disease through specific actions in research, advocacy, communication, and implementation.

This first phase has seen progress in the organization and expansion of the network's participant base and real work in the field, building on the evidence that household water management can contribute to meeting the Millennium Development Goals for child survival and water security. This fieldwork has reaffirmed the conclusion of a WHO-sponsored review: simple, low-cost interventions for home water treatment and storage lead to dramatic improvements in drinking water quality and reductions in diarrheal disease (1).

The Safe Water System, developed by the Centers for Disease Control and Prevention (CDC), the Pan American Health Organization (PAHO), and WHO, combines point-of-use water disinfection with locally produced sodium hypochlorite, safe storage in narrow-mouth containers, and community education and has consistently been effective in preventing diarrhea (2,3). In recently published trials, the Safe Water System reduced diarrhea by 24% in Bangladesh (4) and 25% in Guatemala (5). In a 2003 study, the Safe Water System reduced diarrhea by 30% among persons with HIV infection in rural Uganda (6).

In 2003, accounts of field trials of a household-based flocculant-disinfectant for water treatment were published for the first time. Developed by the Procter & Gamble Company and CDC, the intervention combines a chemical flocculant with a timed-release hypochlorite disinfectant. Through precipitation, coagulation, and flocculation, the combined product physically removes a broad range of microbial pathogens and chemicals, including arsenic, and concurrently inactivates remaining microbes with free chlorine (7,8). In a randomized, controlled trial in Guatemala, use of the product reduced the incidence of diarrhea among intervention households by 24%, or 29% when the treated water was stored in a vessel designed specifically for safe storage (5).

In 2003, considerable progress was made in evaluating the impact of household-based filtration. In a large field trial, Rita Colwell and colleagues showed that simple filters made from sari cloth or nylon, combined with appropriate education, reduced cholera by 48% compared to controls (9). Locally produced slow sand and ceramic filters were evaluated by Massachusetts Institute of Technology postgraduate students (10-12). In a trial in Bolivia, locally fabricated filters that used imported ceramic candles eliminated all detectable fecal coliform bacteria in household drinking water and reduced levels of diarrhea by 64% (13).

In 2004, a systematic review of 57 studies assessed the extent and causes of microbiological contamination of household drinking water between the source and the consumer (14). The reviewers concluded that water quality declines substantially after collection and recommended household treatment and safe storage of water. A systematic review of the health impact of improved water quality is under way, driven in part by the burgeoning evidence indicating that substantial health gains result when water is treated in households and protected against recontamination (15,16).

In Nairobi, network members will review recent progress and plan their next steps for advancing household-based water management. Stakeholders from all organizations are urged to participate in, contribute to, and take full advantage of this important new movement in the battle against waterborne disease. For more information on the network and to register for the Nairobi meeting, readers are referred to: http://www.cdc.gov/safewater/network.htm

References

(1.) Sobsey MD. (2002). Managing water in the home: accelerated health gains from improved water supply. Geneva: WHO (WHO/SDE/WSH/02.07) [cited 2004 May 4]. Available from: http://www.who.int/water_sanitation_health/dwq/wsh0207/en/

(2.) Mintz ED, Reiff FM, Tauxe RV. Safe water treatment and storage in the home: a practical new strategy to prevent waterborne disease. JAMA. 1995;273:948-53.

(3.) Mintz ED, Bartram J, Lochery P, Wegelin M. Not just a drop in the bucket: expanding access to point-of-use water treatment systems. Am J Public Health. 2001;91: 1565-70.

(4.) Sobsey MD, Handzel T, Venczel L. Chlorination and safe storage of household drinking water in developing countries to reduce waterborne disease. Water Sci Technol. 2003;47:221-8.

(5.) Reller ME, Mendoza CE, Lopez MB, Alvarez M, Hoekstra RM, Olson CA, et al. A randomized controlled trial of household-based flocculant-disinfectant drinking water treatment for diarrhea prevention in rural Guatemala. Am J Trop Med Hyg. 2002;64:411-9.

(6.) Lule, JR, Mermin J, Malamba S, Coutinho A, Kizito F, Nakanjako D, et al. Effect of safe water and cotrimoxazole on diarrhea among people with HIV and their families. In: Abstracts of the International Conference on AIDS and Sexually Transmitted Diseases in Africa (ICASA). Nairobi, Kenya, September 2003. [cited 2004 May 4]. Available from: http://www.icasafrica.org/icasa_abstractbook.pdf

(7.) Souter PF, Cruickshank GD, Tankersesville MZ, Keswick BH, Ellis BD, Langworthy DE, et al. Evaluation of a new water treatment for point-of-use household applications to remove microorganisms and arsenic from drinking water. Journal of Water & and Health. 2003;1:73-84.

(8.) Rangel, JM, Lopez B, Alvarez Mejia MA, Mendoza C, Luby S. A novel technology to improve drinking water quality: a microbiological evaluation of in-home flocculation and chlorination in rural Guatemala. Journal of Water and Health. 2003;1:15-22.

(9.) Colwell RR, Huq A, Islam MS, Aziz KMA, Yunus M, Khan NH, et al. Reduction of cholera in Bangladeshi villages by simple filtration. Proc. Nat Acad Sci USA. 2003; 100:1051-5.

(10.) Dies RW. Development of a ceramic water filter for Nepal. [thesis]. Cambridge (MA): Massachusetts Institute of Technology; 2004. [cited 2004 May 5]. Available at: http://ceemeng.mit.edu/~water/documents.html

(11.) Pincus MI. Safe household drinking water. [thesis]. Cambridge (MA): Massachusetts Institute of Technology; 2004. [cited 2004 May 5]. Available from: http://ceemeng. mit.edu/~water/documents.html

(12.) Ngai T, Walewijk S. The arsenic biosand filter (abf) project: design of an appropriate household drinking water filter for rural Nepal [thesis]. Cambridge (MA): Massachusetts Institute of Technology; 2004. [cited 2004 May 5]. Available from: http://ceemeng.mit.edu/~water/documents.html

(13.) Clasen T, Brown J, Suntura O, Collin S, & Cairncross S. Reducing diarrhoea through household-based ceramic filtration of drinking water: a randomized, controlled trial in Bolivia. Am J Trop Med Hyg. 2004:in press.

(14.) Wright J, Gundry S, Conroy R. Household drinking water in developing countries: a systematic review of microbiological contamination between source and point of use. Trop Med Int Health. 2004;9:106-17.

(15.) Clasen T, Roberts I, Rabie T, Cairncross S. Interventions to improve water quality for preventing infectious diarrhoea (Protocol for a Cochrane Review). In: The Cochrane Library, Issue 2, 2004. Oxford: Update Software. [cited 2004 May 4]. Available at: http://www.update-software.com/clibngon.htm

(16.) Clasen TF, Cairncross S. Household water management: refining the dominant paradigm. Trop Med Int Health. 2004;9:187-91.

Thomas F. Clasen * and Eric D. Mintz ([dagger])

* London School of Hygiene and Tropical Medicine, London, United Kingdom; and ([dagger]) Centers for Disease Control and Prevention, Atlanta, Georgia, USA

Address for correspondence: Eric D. Mintz, Centers for Disease Control and Prevention, 1600 Clifton Road, Mailstop A38, Atlanta, GA 30333, USA; fax: [phone]; email: [e-mail]