By J.T. Macy & R.E. Quick
In 2002, just 12 years after the end of the United Nations-declared International Drinking Water and Sanitation Decade, the lack of access to safe water remains a problem for over a billion people worldwide, and inadequate sanitation services affect at least 2.4 billion people, according to the Global Water Supply & Sanitation Assessment 2000 Report.9
Diarrheal diseases, which are frequently transmitted by contaminated water, continue to be a leading cause of morbidity and mortality among children under 5 years of age in developing countries. Estimates of annual total mortality from diarrheal diseases range from 2.5 million to 3.5 million. More than 80 percent of cases are among children under age 5.2 Total morbidity is estimated at 4 billion episodes per year, of which 30 percent are, according to one estimate, related to contaminated water. Thus, there are roughly 1.2 billion episodes of water-related diarrheal diseases annually.2 The water quality crisis is highlighted by the continuing 7th cholera pandemic that started in Latin America in Peru in 1991 and swept across the region causing more than 1.2 million cases and more than 12,000 deaths.3
There are a number of reasons for the persistence of these problems, in spite of the investment of billions of dollars in water and sanitation services by donor agencies and governments. Population growth and shifts from rural to urban areas have stressed existing water and sanitary infrastructure and exceeded the capacity of many countries to keep up with demand for services. In many rural areas, water and sanitary infrastructure are inadequate or non-existent because of dispersed populations and poor transportation infrastructure. Large population dislocations caused by armed conflict and natural disasters have created enormous logistical problems in providing water and sanitation services. Finally, inadequate maintenance of water and sanitation infrastructure has, in some instances, led to failures of technology.
The Safe Water System
In response to the need for inexpensive, alternative means of water treatment and storage in the short to medium term, the U.S. Centers for Disease Control and Prevention (CDC) and the Pan American Health Organization/World Health Organization (PAHO/WHO) developed the Safe Water System,1 a household-based water quality intervention (see www.cdc.gov/safewater/). The intervention has three main components—point-of-use (POU) treatment, safe storage and behavior change techniques.
POU water treatment is promoted through the use of sodium hypochlorite solution as a disinfectant that’s produced in the community from water and salt using an electrolytic cell or manufactured by a private company. Treatment with sodium hypochlorite is effective, safe, inexpensive and provides a residual effect against recontamination. In Ecuador, the Ministry of Health created a national program for the local production of sodium hypochlorite solution for POU water disinfection (see Figure 1).
Safe water storage prevents recontamination of treated water and can be accomplished through the use of containers with a narrow mouth, tight-fitting lid and a spigot for removing water. If such a storage container is used, people are less likely to introduce dirty hands or cups into the water. Street vendors in Guatemala City used safe storage containers to make and store beverages free from contamination (see Figure 2).
Behavior change techniques help ensure proper use of the intervention by the target population. Techniques that have been field-tested include social marketing, community mobilization, and motivational interviewing. These methods serve to increase awareness of the link between contaminated water and disease and the benefits of consuming safe water. The goal of these methods is to motivate the target population to purchase and properly use safe water storage vessels and disinfectant. In Bolivia, the Safe Water System was socially marketed under the brand name “CLARO” (see Figure 3).
The need for safe water in Latin America and throughout the developing world is great, and children continue to be at risk for illness and death due to diarrheal diseases. The Safe Water System has been shown to reduce the risk of diarrheal diseases by 44-to-85 percent in field trials performed in South America, Africa and Central Asia.5,6,7 The Safe Water System is inexpensive, simple to use, adaptable to different conditions and can be implemented in a relatively short period of time. In developing country communities with poor water quality, successful implementation of the Safe Water System can improve water quality and health. Further work is needed to explore innovative approaches — such as private sector partnerships and cost recovery mechanisms—to facilitate the expansion of the Safe Water System to other countries. Finally, further research on behavior change strategies is needed to determine the most effective approaches to motivating target populations to use the Safe Water System.
- Centers for Disease Control and Prevention, Safe Water Systems for the Developing World: A Handbook for Implementing Household-Based Water Treatment and Safe Storage Projects, CDC, Atlanta, 2000.
- Ford, T.E., “Microbiological Safety of Drinking Water: United States and Global Perspectives,” Environmental Health Perspectives, 107, 191-206, 1999.
- Pan American Health Organization, “Cholera: Number of Cases and Deaths in the Americas, 1991-2001 (by country and year),” 2002: http://www.paho.org/English/HCP/HCT/EER/cholera-cases-deaths-91-01.htm.
- Quick, R., et al., “A new strategy for waterborne disease transmission,” 23rd WEDC Conference, Durban, South Africa, 1997.
- Quick, R., L. Venczel, E. Mintz, L. Soleto, J. Aparicio, M. Gironaz, L. Hutwagner, K. Greene, C. Bopp, K. Maloney, D. Chavez, M. Sobsey and R. Tauxe, “Diarrhea prevention in Bolivia through point-of-use disinfection and safe storage: a promising new strategy,” Epidemiology & Infection, 122: 83-90, 1999.
- Quick, R.E., A. Kimura, A. Thevos, et al., “Diarrhea Prevention through Household-Level Water Disinfection and Safe Storage in Zambia,” American Journal of Tropical Medicine and Hygiene (in press).
- Semenza, J., L. Roberts, A. Henderson, J. Bogan and C. Rubin, “Water distribution system and diarrheal disease transmission: a case study in Uzbekistan,” American Journal of Tropical Medicine and Hygiene, 59: 941-6, 1998.
- Sobel, J., B. Mahon, C. Mendoza, D. Passaro, F. Cano, K. Baier, F. Racioppi, L. Hutwagner and E. Mintz, “Reduction of fecal contamination of street-vended beverages in Guatemala by a simple system for water purification and storage, handwash-ing, and beverage storage,” American Journal of Tropical Medicine and Hygiene, 59: 380-387, 1998.
- World Health Organization and United Nations Children’s Fund (UNICEF), Global Water Supply and Sanitation Assessment 2000 Report, WHO, Geneva, 80 pp., 2000.
About the authors
Jonathan T. Macy, MPH, is an epidemiologist with the Foodborne and Diarrheal Diseases Branch, Division of Bacterial and Mycotic Diseases, National Center for Infectious Diseases, Centers for Disease Control and Prevention, in Atlanta, U.S.A. He can be reached at (404) 639-2206 or email: firstname.lastname@example.org.
Robert E. Quick, M.D., MPH, is a medical epidemiologist with the Foodborne and Diarrheal Diseases Branch, Division of Bacterial and Mycotic Diseases, National Center for Infectious Diseases, Centers for Disease Control and Prevention in Atlanta, U.S.A. He can be reached at (404) 639-2206 or email: email@example.com.