Traspaso de pérdidas y ganancias a la cuenta utilidad neta del ejercicio

Diarrhoeal disease is one of the leading killers of children in the world (ESREY et al., 1990). SNYDER and MERSON (1982), estimated that there were more than 875 million cases of diarrhoea and 4.6 million deaths annually in Africa, Asia, and Latin America, but in 1985, nearly 3 billion of episodes of diarrhoea were estimated to have occurred in the developing countries, leading to the death of 5 million persons, 80 percent of them under five years of age (MARTINES et al., 1991). Morbidity rates are generally higher in older infants

(6-11 months) and children 12-23 months, while mortality peaks in children under 2. Early childhood mortality in Northeastern Brazil is among the highest in the world, exceeding 140 per thousand during the first five years of life. For more than 52% of all such deaths recorded, diarrhoea is listed as either the primary or an associated cause of death (GUERRANT et al.,

1983).

Measurement of diarrhoeal morbidity is difficult, due partly to the lack of a satisfactory definition of diarrhoea (SNYDER and MERSON, 1982). Several studies on diarrhoeal morbidity have been reported but there are major differences in the terms used to define a diarrhoeal episode. The definitions have varied from the relatively simple ones such as "more than two watery or loose motions in 24 hours", as used in a Bangladesh study (RAHAMAN et al., 1979) , to a more complex one

in Guatemala, "under 1 year of age: 5 or more liquid stools per 24 hours; over 1 year: 3 or more liquid or semi-liquid stools preceded by 2 weeks of normal stools" (SCRIMSHAW et

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W E I R et al. (1952) questioned the efficacy of latrine con­ struction in Egyptian villages for control of diarrhoeal diseases while housing remained unchanged and economic condi­ tions confined people to unhygienic environments. The latrines w e r e u s e d by the people only when it was convenient to do so. It is not surprising that opportunities for transmission of pathogens were not reduced by the measures employed. Simi­ larly, KOURANY et al. (1971) pointed out that access to flush toilets for the disposal of excreta had no benefit with respect to frequency of infection among the Panamanian children, since the facilities available were notoriously inadequate and were shared communally.

KOOPMAN (1980) studying sewage disposal, water supply and endemic diarrhoea in an urban slum of Cali, Colombia, found that although diarrhoea incidence rates varied markedly by age group, the relationship of these rates to household sewage disposal did not vary significantly by age group. The tran­ sient association of increased diarrhoea in surrounding populations and the variation in this increase with exposure to the sewage of the local population led to the conclusion

that the community spread of diarrhoea, related to inadequate sewage disposal, was even more important than household spread. Houses with no provision for the removal of excreta had 60% more cases of diarrhoea than those with a latrine, and

127% m o r e than those with a sewer.

ESREY et al. (1990) added 17 more studies to their review of 67 studies from 28 countries (ESREY et al., 1985) and con­ cluded that, taken as a whole, they provided strong evidence that improvements in water supplies, sanitation facilities and hygiene practices may have a significant impact on diarrhoeal diseases. Improvements in water quantity and excreta disposal facilities appeared to have a greater impact than improvements in water quality although, in most cases, it was difficult to separate clearly the effect of water quantity and quality. They found that improved water supplies and sanitation interventions demonstrated a median reduction of 22% in diarrhoeal morbidity rates of children under 5 years of age. If only the studies of better quality were considered, the median reduction was 26%. The impact of sanitation alone also was examined in 30 studies, of which 21 reported health improvements. Calculations showed a median percent reduction of 22%. Of the better studies the median was 36%. The increasing effect associated with an upgrading of interventions may be related to the number of family or community members using the facility or the number of times in which it is used by each individual.

VANDERSLICE and BRISCOE (1995) studying the effects of environmental interventions on diarrhoeal disease in Cebu, Philippines, found that the effects of water quality, household sanitation, and community sanitation were strong, consistent, and statistically significant on diarrhoea in children from birth to 2 years of age. For households without in-house connections, providing such a connection would result in a m e a n reduction in the predicted probability of diarrhoea in children of 12%. For households without private or well- maintained excreta disposal facilities, the provision of such facilities was estimated to reduce childhood diarrhoea by 42%, and for households with excreta around the house, eliminating the excreta would result in 30% less diarrhoea among affected children. Improving drinking water quality would have no effect in neighbourhoods with very poor environmental sanitation, but for households with good quality drinking water, improving the level of community sanitation would reduce diarrhoeal prevalence by 25%. They conclude, raising the issue of conceptual and empirical difficulties to conduct studies that take into account the interactions between environmental interventions.