Effect of communal piped water supply on pattern of water use and transmission of schistosomiasis haematobia in an endemic area of Kenya

An attempt was made to examine the long-term impact of the introduction of communal piped water supply on pattern of water use and transmission of schistosomiasis haematobia in an endemic area of Kenya. In the study area, Mtsangatamu, a control program based on repeated selective mass-chemotherapy had been carried out for 6 years from 1987 to 1993. The pre-treatment overall prevalence and intensity of infection in 1987 were 59.2% and 10.9 eggs/10 ml of urine (Muhoho et al., 1997). During the control program, the prevalence was kept at a low range of 20 to 40% (Muhoho et al., 1994). At the end of the program, in 1994, gravity-fed water supply was provided to the village. Although the water facilities were damaged by flooding in 1998, new and further expanded gravity-fed water supply facilities consisting of 7 standpipes were introduced in 2000. The follow-up survey done in 1999 revealed reduced prevalence and intensity of infection, I.e. 23.0% and 1.2 eggs/ 10 ml of urine (unpublished data). The present study was carried out in 2006, 6 years after the last mass-chemotherapy. Urine examination showed that the prevalence and intensity of infection had return to 52.2% and 7.4 eggs/10 ml, nearly the same level as the pre-treatment level. The results of our study demonstrated that, over the long-term, the gravity-fed water supply facilities had little impact on the overall prevalence and intensity of infection in this village. However, analysis of the spatial pattern of infection, observation of human water contact at the river and a questionnaire on water use shed light on the possible impact of water supply on human water contact. The younger people (5-19 years old) with easy access to the standpipes showed a lower prevalence and intensity of infection, while the relationship was not clear in other age groups. The result of the questionnaire indicated that the long distance from household to standpipe was the major factor limiting the use of the communal tap water. Most of the villagers who used piped water as the main source of water lived within 800 m of the nearest standpipe, and villagers who used river water exclusively lived beyond that distance. Observation of water-related activities at the communal water facilities also indicated that the residents who lived near standpipes used the piped water more frequently. The frequency of total visits to river water sites did not differ between residents who lived near and far from the standpipe. However, water contact in the form of playing, the highest risk behavior, was observed exclusively among children who lived far (>250m) from standpipes, although the number of observations was small. The present study demonstrated that the water facilities had little effect on the dispersed population but might have a beneficial effect on some villagers given easy access to standpipes