Childhood diarrhoea and its prevention in Nicaragua
Phd. Thesis. University of Maastricht
By Anna Cornelia Gorter
December 1998
SUMMARY
In Villa Carlos Fonseca, west of Managua in a rural area of Nicaragua, an integrated programme of diarrhoeal disease research was performed.
The first study was a case-control study to investigate the relative importance of water-borne versus water-washed transmission mechanisms in childhood diarrhoeal disease. As part of this study the microbiological quality and the amount of water consumed was investigated. Traditional water sources were grossly contaminated whereas piped water sources were much cleaner. A close association between rainfall and faecal contamination was demonstrated. The water of traditional sources was more contaminated in large communities compared to small communities. Factors found to affect domestic water use were household size, site of clothes washing, the type of water source, mother's level of schooling, distance to the water source, wealth, and the ownership of cattle. A decrease in the distance to the water source from 1000 to 10 meters was associated with a clear increase in per capita water consumption. Families where the mother had at least 6 years of schooling used more water than families where the mother had no formal education.
In our case-control study 1229 children under the age of 5 were matched to an equal number of children of the same age presenting with other illnesses unrelated to water and sanitation. In spite of marked differences in water quality between the different types of water supply, no effect was found of the water quality on the diarrhoea morbidity. In contrast, there was a clear association between water availability and diarrhoea morbidity. Children from homes with water supplies over 500 metres from the house had much higher incidence rates of diarrhoea than children from houses with their water supply "on the premises". The ownership of a latrine was not found to be significantly related to diarrhoea morbidity. A mother's level of schooling was inversely correlated with the frequency of diarrhoea in her children.
Next we conducted a prospective follow-up study on the hygiene. From the database of the case control study 172 families with a child under the age of 2 years were recruited. Hygiene behaviour was observed and diarrhoea incidence was recorded for 5 months. Of 46 "good" practices studied, 39 were associated with a lower risk of diarrhoea, 5 were unrelated and only for 2 a higher risk was observed. Washing of hands, domestic cleanliness (kitchen, living room, yard) and the use of diapers/underclothes by the child had the strongest protective effect. Schooling and better economic position had a positive influence on general hygiene behaviour. Individual hygiene behaviour appeared to be highly variable.
With the objective to gather information on traditional health beliefs and practices we performed two studies: one ethnographic and the other epidemiological. In the ethnographic study, 70 mothers with children under 2 years were interviewed. In the epidemiological study, 392 mothers with a child under the age of 5 participated, 216 of whom had had diarrhea in the previous two weeks. The studies confirmed that traditional beliefs and practices continue to be important and have a direct influence on the manner in which mothers respond to diarrhoea in their children. Popular knowledge is a result of both traditional and modern medicine. A good program combines traditional and modern concepts. Mothers will feel motivated to change their habits only if they understand the effect of harmful hygienic practices on their children.
We also performed a literature review of the health impact of water supplies, sanitation and hygiene on the incidence of diarrhoeal disease. There is a reasonable consensus that water quality improvements do not generally have as great an impact on health compared to interventions which increase the availability of water or provide human faeces disposal facilities. Those interventions that improve hygienic behaviour at the household level and/or the community level, seem to have the greatest impact. Improving the level of hygiene practices may be highly effective, but depends on the available preconditions such as the mother's level of education, facilities for water and for the disposal of faeces. Social and cultural factors may also have a reinforcing or a restraining influence.
A further literature review was carried out to identify which interventions are most likely to reduce faecal contamination of wells, waterholes and surface water. The few published studies suggest that upgrading wells is effective through improvements such as a windlass, bucket cage, drainage system, lining, head wall and cover when these are applied together. It is not known, however, how effective individual components of the upgrading are in reducing contamination. The provision of pumps seems to be useful in settings with gross contamination, and tube wells are consistently cleaner than hand dug wells.
A final practical result from our studies was the development of the rope pump technology. Rope pumps are now widely promoted as a low cost, easily maintained means to improve water availability in many developing countries. The hand-dug well is the traditional type of water source that is mostly used in rural areas. Facilitating the task of drawing water through the installation of a rope pump will reduce the time that is needed to get water. The total amount of used water will increase. Our study looked at the well water quality under a variety of different conditions, comparing bucket and rope wells, with wells with a windlass and rope pump wells. Results indicated a strong reduction of the faecal coliform contamination of the well water due to the installation of a rope pump, compared to bucket and rope wells. Other factors found to influence the level of contamination of water in hand-dug wells were rainfall, the number of households using the well, the amount of water extracted daily and the distance of the well to the nearest kitchen. The last three factors probably reflect domestic activities around the well.
On the basis of our studies we conclude that improvement of the quantity of water available to people in developing countries can reduce the transmission of diarrhoeal pathogens considerably. Together with other preconditions, such as education, mothers will be able to develop good hygiene at the personal, domestic and community level. Diarrhoea is a major health problem and affects all infants in the developing world. None of the developing countries has full coverage of adequate water supplies and sanitation facilities, and in general they have poor hygiene at the household as well as at the public level. Improvements of one or more of these conditions will improve the health of many infants in these countries...x.