Summary objective To assess the extent and causes of microbiological contamination of household drinking water between source and point-of-use in developing countries. methods A systematic meta-analysis of 57 studies measuring bacteria counts for source water and stored water in the home to assess how contamination varied between settings. results The bacteriological quality of drinking water significantly declines after collection in many settings. The extent of contamination after water collection varies considerably between settings, but is proportionately greater where faecal and total coliform counts in source water are low. conclusions Policies that aim to improve water quality through source improvements may be compromised by post-collection contamination. Safer household water storage and treatment is recommended to prevent this, together with point-of-use water quality monitoring.

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Household drinking water in developing countries: a systematic review of microbiological contamination between source and point‐of‐use

Effect of handwashing on child health: a randomised controlled trial

This document is not issued to the general public and all rights are reserved by the World Health Organization. The document may not be reviewed, abstracted, quoted, reproduced or translated, in part or in whole, without the prior written permission of WHO. No part of this document may be stored in a retrieval system or transmitted in any form or by any means – electronic, mechanical or other without the prior written permission of WHO. The views expressed in documents by named authors are solely the responsibility of those authors. (or The authors alone are responsible for the views expressed in this document) FOREWORD Around 2.2 million die of basic hygiene related diseases, like diarrhoea, every year. The great majority are children in developing countries. Interventions in hygiene, sanitation and water supply make proven contributors to controlling this disease burden. For decades, universal access to safe water and sanitation has been promoted as an essential step in reducing this preventable disease burden Nevertheless the target " universal access " to improved water sources and basic sanitation remains elusive. The " Millenium Declaration " established the lesser but still ambitious goal of halving the proportion of people without access to safe water by 2015. Achieving " universal access " is an important long-term goal. How to accelerate health gains against this long-term backdrop and especially amongst the most affected populations is an important challenge. There is now conclusive evidence that simple, acceptable, low-cost interventions at the household and community level are capable of dramatically improving the microbial quality of household stored water and reducing the attendant risks of diarrheal disease and death. Many different water collection and storage systems and strategies have been developed, described and evaluated on the basis of various criteria for household and community use in developed and developing countries. A variety of physical and chemical treatment methods to improve the microbial quality of water are available and many have been tested and implemented to varying extents in developed and developing countries. Some of these water treatment and storage systems have been tested under controlled conditions in the laboratory and implemented in field to evaluate their ability to produce drinking water of acceptable microbiological quality and to maintain this quality during storage and use. Some of them also have been evaluated in the field for their ability to reduce diarrheal and other waterborne diseases among users. Because of …

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Managing Water in the Home: Accelerated Health Gains from Improved Water Supply

In developing countries, the microbial contamination of household drinking water is implicated in the prevalence of various diseases. This systematic review is concerned with two health outcomes, general diarrhoea and cholera, and their relationship with water quality at point-of-use. Observational studies investigating this relationship are reviewed, as well as studies of home water treatment and storage interventions. For cholera, a clear relationship was found with contaminated water. Home water treatment and storage interventions were also found to reduce cholera. For general diarrhoea, no clear relationship was found with point-of-use water quality, although interventions did significantly reduce diarrhoeal incidence. Reasons for these apparently contradictory results concerning general diarrhoea are discussed and suggestions for further research offered. The policy implications of the findings are also discussed.

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A systematic review of the health outcomes related to household water quality in developing countries

As a result of rapid urbanization in a context of economic constraints, the majority of urban residents in sub-Saharan Africa live in slums often characterized by a lack of basic services such as water and sewerage. Consequently, the urban poor often use inexpensive pit latrines and at the same time may draw domestic water from nearby wells. Overcrowding in slums limits the adequate distance between wells and pit latrines so that micro-organisms migrate from latrines to water sources. Sanitary practices in these overcrowded slums are also poor, leading to contamination of these wells. This study sought to assess sanitary practices of residents of a Kenyan urban slum and fecal contamination of their domestic water sources. This cross-sectional study involved 192 respondents from Langas slum, Kenya. Forty water samples were collected from the water sources used by the respondents for laboratory analysis of coliforms. Of these 40 samples, 31 were from shallow wells, four from deep wells, and five from taps. Multiple-tube fermentation technique was used to enumerate coliform bacteria in water. The study found that most people (91%) in the Langas slum used wells as the main source of domestic water, whereas the rest used tap water. Whereas most people used pit latrines for excreta disposal, a substantial percentage (30%) of children excreted in the open field. The estimated distance between the pit latrines and the wells was generally short with about 40% of the pit latrines being less than 15 m from the wells. The main domestic water sources were found to be highly contaminated with fecal matter. Total coliforms were found in 100% of water samples from shallow wells, while 97% of these samples from shallow wells were positive for thermotolerant coliforms. Three out of the four samples from deep wells were positive for total coliforms, while two of the four samples were positive for thermotolerant coliforms. None of the samples from taps were positive for either total or thermotolerant coliforms. Because the presence of thermotolerant coliforms in water indicates fecal contamination, facilitated by the proximity between the wells and pit latrines, the study suggests that the pit latrines were a major source of contamination of the wells with fecal matter. However, contamination through surface runoff during rains is also plausible as indiscriminate excreta disposal particularly by children was also common. Owing to the fecal contamination, there is a high possibility of the presence of disease pathogens in the water; thus, the water from the wells in Langas may not be suitable for human consumption. To address this problem, treatment of the water at community or household level and intensive behavioral change in sanitary practices are recommended. Efforts should be made to provide regulated tap water to this community and to other slums in sub-Saharan Africa where tap water is not accessible. However, more sampling of different water sources is recommended.

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Quality of Water the Slum Dwellers Use: The Case of a Kenyan Slum

The impact of the installation of a system to supply chlorinated drinking water in Venda, South Africa, on water quality, water use and health status was evaluated by means of questionnaires, examination for skin infections, and microbiological analysis of water samples. Although the water collection journey became shorter in comparison with use of traditional water supplies such as boreholes and unprotected springs, water use per caput showed no increase. The improved water supply showed no contamination with coliforms even after storage. Borehole water exhibited low coliform counts at the source, but after storage a 10- to 15-fold increase took place. Water samples from unprotected springs exhibited high coliform counts, which declined during storage. The prevalence of infectious skin diseases (27·5%) and diarrhoea (3·7%) among pre-schoolchildren showed no correlation with the quality of drinking water or the use of water per caput . Although the prevalence of infectious skin diseases did exhibit a negative correlation with the frequency of washing, no significant health benefit of the improved water supply could be demonstrated in this limited study.

J.G. van der Schroeff

Papers

Hygiene, skin infections and types of water supply in Venda, South Africa.