ENVIRONMENTAL INTERVENTIONS IN DEVELOPING-COUNTRIES - INTERACTIONS AND THEIR IMPLICATIONS

This study assesses the effect of drinking water quality on diarrheal disease in good and poor sanitary conditions using a random sample of 2,355 Filipino infants over the first year of life. The study provides powerful confirmation of the importance of environmental factors on d iarrhea: The effects of water quality, household sanitation, and commu nity sanitation are strong, consistent, and statistically significant. The positive impact of improved water quality is greatest for familie s living under good sanitary conditions, with the effect statistically significant when sanitation is measured at the community level but no t significant when sanitation is measured at the household level. Impr oving drinking water quality would have no effect in neighborhoods wit h very poor environmental sanitation; however, in areas with better co mmunity sanitation, reducing the concentration of fecal coliforms by t wo orders of magnitude would lead to a 40 percent reduction in diarrhe a. Providing private excreta disposal would be expected to reduce diar rhea by 42 percent, while eliminating excreta around the house would l ead to a 30 percent reduction in diarrhea. The findings suggest that i mprovements in both water supply and sanitation are necessary if infan t health in developing countries is to be improved. They also imply th at it is not epidemiologic but behavioral, institutional, and economic factors that should correctly determine the priority of interventions .