The impact of inadequate sanitary conditions on health in developing countries

One of the achievements of the International Drinking Water Supply and Sanitation Decade (1981-1990) is a better understanding of the relationship between poor sanitary conditions and health. This article reviews current knowledge of the major water- and excreta-related diseases and the potential impact of improved sanitary facilities on health. Four health indicators are considered--diarrhoeal diseases, soil-transmitted nematode infections, dracunculiasis (guinea-worm disease) and nutritional status. These constitute some of the major health problems in the developing world. Although there are large variations in morbidity and mortality rates both between and within geographical areas, some global estimates are presented. Children under 5 experience an average of 3.4 episodes of diarrhoea per year and a diarrhoeal mortality rate estimated at 12 per 1,000, leading to 4 million diarrhoea-associated deaths per year. Diarrhoea may also be associated with a sizeable proportion of adult deaths. Approximately 1,000 million people are believed to be infected with Ascaris lumbricoides, 900 million with hookworms and 500 million with Trichuris trichiura. Dracunculiasis, primarily occurring in remote rural areas, is known to be greatly underreported, but estimates suggest that 10 million people are infected each year. Malnutrition is widely prevalent and a common cause or associated cause of child death. The complex issues involved in measuring the health impact of improved sanitary facilities and the mechanisms by which these impacts may occur are discussed. These complexities, plus the differences in sanitary improvements and environmental settings, and the diverse nature of the health indicators considered, all contribute substantial variations in the health impact observed.(ABSTRACT TRUNCATED AT 250 WORDS)