An Automated Microscopic Scoring Method for the γ-H2AX Foci Assay in Human Peripheral Blood Lymphocytes

Ionizing radiation is a potent inducer of DNA damage and a well-documented carcinogen. Biological dosimetry comprises the detection of biological effects induced by exposure to ionizing radiation to make an individual dose assessment. This is pertinent in the framework of radiation emergencies, where health assessments and planning of clinical treatment for exposed victims are critical. Since DNA double strand breaks (DSB) are considered to be the most lethal form of radiation-induced DNA damage, this protocol presents a method to detect DNA DSB in blood samples. The methodology is based on the detection of a fluorescent labelled phosphorylated DNA repair protein, namely, γ-H2AX. The use of an automated microscopy platform to score the number of γ-H2AX foci per cell allows a standardized analysis with a significant decrease in the turn-around time. Therefore, the γ-H2AX assay has the potential to be one of the fastest and sensitive assays for biological dosimetry. In this protocol, whole blood samples from healthy adult volunteers will be processed and irradiated in vitro in order to illustrate the usage of the automated and sensitive γ-H2AX foci assay for biodosimetry applications. An automated slide scanning system and analysis platform with an integrated fluorescence microscope is used, which allows the fast, automatic scoring of DNA DSB with a reduced degree of bias.

Adherence to Point-of-Use Water Treatment over Short-Term Implementation: Parallel Crossover Trials of Flocculation-Disinfection Sachets in Pakistan and Zambia

The health benefits of point-of-use (POU) water treatment can only be realized through high adherence: correct, consistent, and sustained use. We conducted parallel randomized, longitudinal crossover trials measuring short-term adherence to two single-use flocculant-disinfectant sachets in Pakistan and Zambia. In both trials, adherence declined sharply for both products over the eight week surveillance periods, with overall lower adherence to both products in Zambia. There was no significant difference in adherence between the two products. Estimated median daily production of treated water dropped over the crossover period from 2.5 to 1.4 L person^-1 day^-1 (46% decline) in Pakistan and from 1.4 to 1.1 L person^-1 day^-1 (21% decline) in Zambia. The percentage of surveillance points with detectable total chlorine in household drinking water declined from 70% to 49% in Pakistan and rose marginally from 28% to 30% in Zambia. The relatively low and decreasing adherence observed in this study suggests that these products would have provided little protection from waterborne disease risk in these settings. Our findings underscore the challenge of achieving high adherence to POU water treatment, even under conditions of short-term adoption with intensive follow-up.

The public health significance of latrines discharging to groundwater used for drinking

Faecal contamination of groundwater from pit latrines is widely perceived as a major threat to the safety of drinking water for several billion people in rural and peri-urban areas worldwide. On the floodplains of the Ganges-Brahmaputra-Meghna delta in Bangladesh, we constructed latrines and monitored piezometer nests monthly for two years. We detected faecal coliforms (FC) in 3.3-23.3% of samples at four sites. We differentiate a near-field, characterised by high concentrations and frequent, persistent and contiguous contamination in all directions, and a far-field characterised by rare, impersistent, discontinuous low-level detections in variable directions. Far-field FC concentrations at four sites exceeded 0 and 10 cfu/100 ml in 2.4-9.6% and 0.2-2.3% of sampling events respectively. The lesser contamination of in-situ groundwater compared to water at the point-of-collection from domestic wells, which itself is less contaminated than at the point-of-consumption, demonstrates the importance of recontamination in the well-pump system. We present a conceptual model comprising four sub-pathways: the latrine-aquifer interface (near-field); groundwater flowing from latrine to well (far-field); the well-pump system; and post-collection handling and storage. Applying a hypothetical dose-response model suggests that 1-2% of the diarrhoeal disease burden from drinking water is derived from the aquifer, 29% from the well-pump system, and 70% from post-collection handling. The important implications are (i) that leakage from pit latrines is a minor contributor to faecal contamination of drinking water in alluvial-deltaic terrains; (ii) fears of increased groundwater pollution should not constrain expanding latrine coverage, and (iii) that more attention should be given to reducing contamination around the well-head.

Interventions to improve water quality for preventing diarrhoea

BACKGROUND

Diarrhoeal diseases are a leading cause of mortality and morbidity, especially among young children in developing countries. While many of the infectious agents associated with diarrhoeal disease are potentially waterborne, the evidence for reducing diarrhoea in settings where it is endemic by improving the microbiological quality of drinking water has been equivocal.

OBJECTIVES

To assess the effectiveness of interventions to improve water quality for preventing diarrhoea.

SEARCH STRATEGY

We searched the Cochrane Infectious Diseases Group Specialized Register (December 2005), CENTRAL (The Cochrane Library 2005, Issue 4), MEDLINE (December 2005), EMBASE (December 2005), and LILACS (December 2005). We also handsearched relevant conference proceedings, contacted researchers and organizations working in the field, and checked references from identified studies.

SELECTION CRITERIA

Randomized and quasi-randomized controlled trials comparing interventions aimed at improving the microbiological quality of drinking water with no intervention in children and adults living in settings where diarrhoeal disease is endemic.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed trial quality and extracted data. We used meta-analyses to estimate pooled measures of effect, where appropriate, and investigated potential sources of heterogeneity using subgroup analyses.

MAIN RESULTS

Thirty trials (including 38 independent comparisons) covering over 53,000 participants met the inclusion criteria. Differences between the trials limited the comparability of results and pooling by meta-analysis. In general, the evidence suggests that interventions to improve the microbiological quality of drinking water are effective in preventing diarrhoea both for populations of all ages and children less than five years old. Subgroup analyses suggest that household interventions are more effective in preventing diarrhoea than interventions at the water source. Effectiveness was positively associated with compliance. Effectiveness was not conditioned on the presence of improved water supplies or sanitation in the study setting, and was not enhanced by combining the intervention to improve water quality with other common environmental interventions intended to prevent diarrhoea.

AUTHORS' CONCLUSIONS

Interventions to improve water quality are generally effective in preventing diarrhoea, and interventions to improve water quality at the household level are more effective than those at the source. Significant heterogeneity among the trials suggests that the actual level of effectiveness may depend on a variety of conditions that research to date cannot fully explain. Rigorous, blinded, multi-arm randomized controlled trials conducted over a longer duration in a variety if settings may help clarify the potential effectiveness.

Asymptomatic giardiasis and growth in young children; a longitudinal study in Salvador, Brazil

This study sought to assess the effect of giardiasis on growth of young children. In Salvador, northeast Brazil, 597 children initially aged 6 to 45 months were followed for a year in 1998/9, measured anthropometrically thrice, every 6 months, and monitored for diarrhoea prevalence twice weekly. Stool samples were collected and examined during the second round of anthropometry, and infected children were treated 39 days later, on average (S.D. 20 days). For each 6-month interval, the gains in z-scores of infected and uninfected children were compared, after adjustment for potential confounding factors, including longitudinal prevalence of diarrhoea. No significant difference was found for the first interval but in the second, the gain in adjusted height-for-age z-score was 0.09 less in infected than uninfected children, equivalent to a difference in height gain of 0.5 cm. The shortfall in growth was greater in children who remained free of diarrhoea, and was significantly correlated with the proportion of the second interval during which the child had remained untreated. We conclude that Giardia can impede child growth even when asymptomatic, presumably through malabsorption. This finding challenges the view that young children found to have asymptomatic giardiasis in developing countries should not be treated.

Global eradication of Guinea worm

Little more than a decade ago, it was estimated that over three million cases of dracunculiasis occurred worldwide. Since then, the numbers have fallen dramatically, thanks to the water supply initiatives of the 1980s and, more recently, the national guinea worm eradication programmes implemented in a score of endemic countries. Hervé Periès and Sandy Cairncross discuss how eradication will require the containment of cases in the remaining endemic areas, together with the simultaneous strengthening of surveillance to permit the certification of eradication. This aim requires existing strategies to be adapted to maintain their efficacy and also to improve their sustainability and cost-effectiveness. Sudan with its civil war, and more than a hundred thousand reported cases, remains a major obstacle to rapid achievement of the goal.

Is there an association between bacteriological drinking water quality and childhood diarrhoea in developing countries?

To investigate the association between bacteriological drinking water quality and incidence of diarrhoea, we conducted a 1-year prospective study in the southern Punjab, Pakistan. Diarrhoea episodes, drinking water sources and drinking water quality were monitored weekly among children younger than 5 years in 200 households. We found no association between the incidence of childhood diarrhoea and the number of Escherichia coli in the drinking water sources (the public domain). A possible trend was seen relating the number of E. coli in the household storage containers (the domestic domain) and diarrhoea incidence, but this did not reach statistical significance. Faecal contamination levels in household water containers were generally high even when the source water was of good quality. Under conditions such as this, it is questionable whether public water treatment will have a significant impact on the incidence of endemic childhood diarrhoea.

Environmental interventions and the pattern of geohelminth infections in Salvador, Brazil

This paper reports a longitudinal study, conducted in 1989/90, of 1893 children aged 5 to 14 years in 9 poor urban areas of the city of Salvador (population 2.44 million), capital of Bahia State in northeast Brazil. Stool examinations were performed to measure nematode infection and reinfection 9 months after treatment, and an extensive questionnaire was applied to collect information on each child and on the conditions of the household. Comparison of areas with different levels of infrastructure showed the following trends as the level of community sanitation improved: clustering of cases by household became more significant, predisposition of individuals to reinfection and to heavy infection became more marked, and infections with different species were increasingly aggregated in the same individuals. These results suggest that sewerage and drainage can significantly reduce transmission of intestinal nematode infections in the public domain, but that other measures are required to control transmission within the household.

Risk factors for infection with Giardia duodenalis in pre-school children in the city of Salvador, Brazil

A cross-sectional study of 694 children aged 2 to 45 months selected from 30 clusters throughout the city of Salvador, Bahia (pop. 2.3 million) was carried out as part of a longitudinal study of diarrhoea in order to identify risk factors for infection with Giardia duodenalis. Variables studied included three social and demographic factors (such as mother's education and marital status), five relating to the peri-domestic environment (rubbish disposal, open sewers, paving of the street), seven relating to the home itself (house construction, susceptibility to flooding, water supply and sanitation) as well as a score for hygiene behaviour based on structured observation. After multivariate analysis using a hierarchical model, only four significant risk factors were found: (a) number of children in the household under five years (b) rubbish not collected from the house (c) presence of visible sewage nearby, and (d) absence of a toilet. All four were significant at the 1% level.

Childhood diarrhea and observed hygiene behavior in Salvador, Brazil

Brief biweekly home visits, made as part of a cohort study of diarrhea in young children under age 5 years that was carried out in Salvador, Brazil, in 1998-1999, were used as a low-cost way to collect structured observation data on domestic hygiene behavior. Field-workers were trained to check a list of 23 forms of hygienic or unhygienic behavior by the child or the child's caretaker, if any behaviors were seen during the visit. Children were grouped according to whether mainly unhygienic behavior or mainly hygienic behavior had been recorded. This permitted study of the determinants of hygiene behavior and of its role in the transmission or prevention of diarrheal disease. Observations were recorded on roughly one visit in 20. Households with adequate excreta disposal were significantly more likely to be in the "mainly hygienic" group. The prevalence of diarrhea among children for whom mainly unhygienic behavior was recorded was 2.2 times that among children in the "mainly hygienic" group. The relative risk for prevalence was 2.2 (95% confidence interval: 1.7, 2.8). The relative risk fell to 1.9 (95% confidence interval: 1.5, 2.5) after data were controlled for confounding, but the difference was still highly significant.

Sanitation in the developing world: current status and future solutions

More than a third of the world's population (2.4 billion people) lacks access to adequate excreta disposal. Four in five of these unserved people are in Asia, with approximately one in five in both India and China, respectively. Even in large Asian cities, less than half of those served are using sewerage systems; the others use on-site systems, from pit latrines to septic tanks. Most have been installed by householders or builders employed by them, rather than by government or municipal agencies. Governments, international agencies and municipalities can never hope to meet the immense gap in provision unless they promote sanitation with a marketing approach. A latrine is a consumer durable which must be sold. It is often considered that the constraint to increasing sanitation coverage is a lack of demand, but there is often a lack of supply of appropriate products, and latrine designs are often too expensive for the poor, requiring subsidies which are captured by the better-off. More market research is needed to define the right product and how best to stimulate demand. Where subsidies are used, the promotion, not the production of the latrines must be subsidised to prevent middle-class capture of the subsidy. Promotion is probably best performed by different agencies from those that build latrines. The expertise and marketing capacity of the private sector needs to be brought into play, and public bodies must learn to assist it effectively in bringing sanitation to all.

The epidemiology of hepatitis A in Rio de Janeiro: environmental and domestic risk factors

A serological study of hepatitis A was carried out in low-income areas scheduled for a major sanitation programme in Rio de Janeiro, Brazil. Blood spots were collected by finger puncture and transported on filter paper, and total antibodies to hepatitis A virus were detected by ELISA. Households were also interviewed to collect information on their environmental conditions and socio-economic status. A generalized linear model using a complementary log-log function was fitted to the data, using the logarithm of age as an explanatory variable to derive adjusted rate ratios (RR). The risk of infection was greater among households with 2-3 members per room (RR = 1.4; 95% CI = 1.04-1.8) or more than three per room (RR = 1.5; 95% CI = 1.2-2.0). People living on hilltops (RR = 1.5; 95% CI = 1.02-2.2), near to open sewers (RR = 1.2; 95% CI = 1.03-1.5) or lacking a kitchen (RR = 1.4; 95% CI = 1.08-1.9) were also at greater risk than others. The number of taps and water-using fittings in the house was associated with a protective effect (RR = 0.9 for each tap; 95% CI = 0.9-0.98). A significant protective association was found with maternal education but not with gender or household income. The results do not suggest a strong association with water quality. Ownership of a ceramic water filter was associated with a protective effect on the margin of significance, but the practice of boiling drinking-water was not, nor was the type of water source used. The results suggest that that the risk of infection with hepatitis A is determined by environmental variables in the domestic and public domains.

Review of the evidence base for the 'F' and 'E' components of the SAFE strategy for trachoma control

Community control of trachoma as a blinding disease is based on the SAFE strategy of Surgery, Antibiotic therapy, Facial cleanliness and Environmental improvement. Surgery and antibiotic therapy currently dominate most programmes. Blindness from trachoma results from frequent infections repeated over many years, so ultimate success requires the reduction of transmission. This is only likely to be sustainable through the F and E components of SAFE. Environmental improvement with access to water, enhanced hygiene and better sanitation reduces trachoma transmission and the blinding sequelae eventually disappear. Transmission routes and factors that cause this are not known and consequently no single specific tool for F and E is in place. Evidence from intervention studies shows that the promotion of face-washing gave modest gains for intense effort and a pilot study showed that trachoma transmission was reduced in the absence of eye-seeking flies. Other studies have shown that latrines and improved access to water are associated with a lower prevalence of active trachoma. There is likely to be a long-term beneficial effect of a combination of improved water supplies, provision of latrines, facial hygiene promotion through established infrastructure and control of eye-seeking flies. Each of these interventions offers additional public health and other benefits in its own right. Further research on the routes of transmission, the role of hygiene and means of sustainable fly control should be a priority.

Domestic hygiene and diarrhoea - pinpointing the problem

Improving domestic hygiene practices is potentially one of the most effective means of reducing the global burden of diarrhoeal diseases in children. However, encouraging behaviour change is a complex and uncertain business. If hygiene promotion is to succeed, it needs to identify and target only those few hygiene practices which are the major source of risk in any setting. Using biological reasoning, we hypothesize that any behaviours which prevent stools from getting into the domestic arena, the child's main habitat, are likely to have a greater impact on health than those practices which prevent pathogens in the environment from being ingested. Hence safe stool disposal, a primary barrier to transmission, may be more important than hand-washing before eating, which constitutes a secondary barrier, for example. We review the epidemiological evidence for the effect of primary and secondary barrier behaviours and suggest that it supports this conclusion. In the absence of local evidence to the contrary, hygiene promotion programmes should give priority to the safe disposal of faecal material and the adequate washing of hands after contact with adult and child stools.

Twenty years of cutaneous leishmaniasis in Aleppo, Syria

Cutaneous leishmaniasis caused by Leishmania tropica has long been associated with Aleppo in Syria. For 20 years up to the mid-1980s, the number of cases reported annually in the city and environs has remained low, not exceeding a few hundred. Since then, there has been a sudden increase to several thousand cases reported each year. The increase seems too great and too sudden to be attributable to improved case detection. Insecticide spraying, begun in 1991, was followed by a reduction in number of cases in 1992, but numbers increased subsequently in spite of continued spraying. The cases are found mainly in areas undergoing development outside the old centre of the city, and may be associated with poor waste disposal and heaps of construction waste.

The impact of health education to promote cloth filters on dracunculiasis prevalence in the northern region, Ghana

This paper describes a health education intervention which was conducted during the 1990 dry season in 3 study villages in the Northern Region of Ghana, to reduce dracunculiasis prevalence in that area by promoting the use of cloth filters for drinking water and avoidance of water contact by sufferers. The impact of the intervention in reducing dracunculiasis prevalence was examined by comparing the period prevalence of infection in 1990 and 1991. The findings demonstrate that the intervention had a measurable but limited impact on dracunculiasis prevalence. Face-to-face health education was successful in persuading 56% of households to buy filters. Ownership of at least one filter for every 10 people in the household was associated with a reduction of at least 20% in the risk of dracunculiasis.

The impact of dracunculiasis on the nutritional status of children in South Kordofan, Sudan

This paper assesses the indirect impact of dracunculiasis on the nutritional status of children under 6 years of age in South Kordofan, Sudan. Weight-for-height anthropometric measurement was used as a measure of the nutritional status of 774 children in 428 households. The indirect impact was investigated by comparing the nutritional status in 1988 of children in 'affected' households, where more than half the adult members had suffered from dracunculiasis in 1987, with children in other households. It was anticipated that when the otherwise able adult members of a households had dracunculiasis they were likely to be disabled by the disease and so prevented from fully performing their agricultural activities, so that the nutritional status of children in the same household would deteriorate in the following year. It was found that in 16.9% of the 136 'affected' households the children were wasted (with mean Z-scores of -2 or less), compared with only 6% of the other households.

Community participation in the eradication of guinea worm disease

As Guinea worm eradication programmes have got under way in endemic countries over the last decade, there has been a shift towards more participatory methods. The approach to surveillance has changed from periodic cross-sectional surveys to monthly village-based reporting of cases by a volunteer village health worker. At the same time, the emphasis regarding control interventions has moved from the provision of safe water supplies to health education. The new approach has proved very effective. The village health volunteers who carry out both surveillance and health education seem to be motivated largely by the social status of their role; still more commitment will be required of them in the final stages of eradication. It is to be hoped that the networks of village health workers established for Guinea worm eradication will find a useful role in health promotion after the worms have gone.

The public and domestic domains in the transmission of disease

This paper discusses the distinction between the transmission of infectious diseases within the domestic domain (the area normally occupied by and under the control of a household) and that in the public domain, which includes public places of work, schooling, commerce and recreation as well as the streets and fields. Whereas transmission in the public domain can allow a single case to cause a large epidemic, transmission in the domestic domain is less dramatic and often ignored, although it may account for a substantial number of cases. Statistical methods are available to estimate the relative importance of the two. To control transmission in the public domain, intervention by public authorities is likely to be required. Two examples show how environmental interventions for disease control tend to address transmission in one or the other domain; interventions are needed in both domains in order to interrupt transmission.

The reliability of retrospective studies using a one-year recall period to measure dracunculiasis prevalence in Ghana

BACKGROUND

Cross-sectional studies are usually adopted to assess the one-year period prevalence of dracunculiasis. They depend upon a recall period of up to one year. This paper aims to examine the degree of accuracy with which villagers in an endemic region recall the occurrence of dracunculiasis during the 12 months prior to a cross-sectional survey.

METHODS

Two types of study were conducted in Tolon, a village in Northern Ghana--retrospective and prospective. Data from people interviewed in a bimonthly survey throughout 1990 were compared with the results of a cross-sectional retrospective study conducted in early 1991.

RESULTS

The results showed that retrospective studies using a recall period of up to one year to measure dracunculiasis prevalence gave only 59.9% of the actual cases, but there were roughly equal numbers of 'false positive' and 'false negative' cases, so that overall prevalence obtained was very close to the correct figure.

CONCLUSIONS

Cross-sectional surveys may be of use to obtain estimates of the one-year period prevalence of dracunculiasis, but are not likely to be reliable enough for more detailed study.

Long-term disability due to guinea worm disease

The village-based surveillance system for guinea worm disease (dracunculiasis), which has been established in all endemic villages in Ghana, was used to carry out a retrospective study of long-term disability due to the disease. A sample of 195 cases was interviewed and examined, 12-18 months after emergence of the worm. Currently continuing pain when walking or working, attributable by its location and date of onset to the episode of dracunculiasis, was reported by 55 persons (28.2%). Some difficulty in performing at least one of 6 everyday physical activities, attributable after careful interview to the episode, was reported by 66 respondents (34.0%), of whom 10 (5.1%) were unable to carry out one of the activities. In one case, the disease had caused impairment of movement of the joints of the right thumb. The prevalence of serious permanent physical impairment among the cases in the study was thus 0.5%.

Water sources and other determinants of dracunculiasis in the northern region of Ghana

This paper describes a study carried out in a rural area of Ghana on the drinking water sources and other determinants of dracunculiasis (guinea worm disease). The results confirm the association between water source choice and the prevalence of the disease. A logistic regression model was used to show the combined effect of several behavioural, biological, and environmental risk factors. The important behavioural factors were related to the head of household, fetching of water, travelling, and farming. Age was found to be an important biological risk factor for dracunculiasis, but the greatest relative risk applied to those who had suffered from guinea worm disease in the previous year. Although males were significantly more infected than females when analysing the raw data, sex did not prove to be a significant risk factor in this model. Village of residence was an important environmental risk factor for dracunculiasis. Factors related to socio-economic status were not associated with the risk of infection. The paper concludes by presenting the policy implications of the study findings.

Elasticity of demand for water in Khartoum, Sudan

A survey of the quantities of water purchased from vendors in the squatter areas of Khartoum, Sudan, was used to assess the effect of the price charged for water and of household income on domestic water consumption. Households in two squatter communities--Meiyo and Karton Kassala--were studied by observation and by interview. In spite of the substantially higher charges, water consumption in Karton Kassala was as high as that in Meiyo. Households within these communities showed no tendency to use less water when paying a higher price for it, or when their income was below average. In other words, no price elasticity or income elasticity was detectable. This was all the more striking in view of the high proportion of income that was spent on water; 17% in Meiyo, and 56% in Karton Kassala. One consequence of this lack of elasticity is that the poorest households devote the greatest percentage of their income to the purchase of water, although the only major item in their household budget which can be sacrificed to make this possible is food. The high price of water in urban Sudan is probably a major cause of the malnutrition prevalent in the squatter areas. Another consequence is that a low-income household's consumer surplus for domestic water is very high, amounting to a substantial proportion of its total income. This has important consequences for the economic appraisal of urban water supply schemes. It also follows that wealthier households with private connections would be willing to pay at least as much for water as that currently paid by the poor.

Determinants of water quality, availability and use in Kurunegala, Sri Lanka

Between January 1987 and February 1988, 4590 homes of children under five years of age were visited in three areas of Kurunegala district, Sri Lanka and data were collected on water related practices. 60% of the population used protected wells, 30% used unprotected sources and 10% used handpumps on boreholes or piped supplies. 90% of households had a source less than 1 km away. Mean water consumption was above 25 litres per capita per day and did not correlate with the distance to source. Samples of drinking water were collected and faecal coliform levels were determined in samples of stored water from 3092 households and in samples from the water sources used by 1043 of these households. The absence or presence of organisms in each sample, and the geometric mean count in samples with organisms were used as indices of contamination. Both indices changed with season and varied between areas and between types of water source. The proportion of positive source samples was uniformly high with the exception of piped supplies and handpumps. The mean count was highest for unprotected sources. There was no evidence that ground water contamination occurred in boreholes. With stored samples, boiling appeared to reduce contamination markedly. The proportion of positive stored water samples was also lower with the use of different vessels for collection and storage, with storage inside the house, and with use of a storage container other than an earthenware pot. Because surface water pollution appears to be important it is proposed that headwalls and drainage aprons be built around unprotected sources. Faecal contamination at the source may have more public health significance than contamination of stored water. In this respect public hygiene may play an important role in reducing water pollution at handpumps or protected wells.

Engineering, mosquitoes and filariasis: a case report

The results of larval surveys were used to assess the relative numbers of mosquitoes breeding in different types of habitat and in different parts of the town of Pondicherry, India. The results illustrate an effective method to set priorities for mosquito control by identifying the most significant breeding sites in a town, and show that they are not necessarily the most obvious, the most extensive or those intuitively most likely.

Water use and health in Mueda, Mozambique

A comparison of domestic water use in 2 villages in Mueda, Mozambique, indicated that a reduction in the length of the water collection journey from 5 h to 10 min was associated with an increase in average water consumption from 4.1 to 11.1 litres per person per day. Bathing and washing clothes accounted for 70% of the increased total. Bathing of children was a regular nightly event in the village with a water supply but almost unknown in the other. Water used for food preparation also increased, suggesting that scarcity of water may also influence diet. A major benefit of water supply is the saving of women's time and effort from water collection. In Mueda, it was an average of 1 3/4 h per day. More than half the time saved was spent on other household tasks, particularly grinding cereals, and on other productive work. Women spent much of the remainder with their children. A trachoma survey, organized as a training exercise for medical students, found a 19% prevalence of trachoma in the village with a water supply, while the prevalence was twice this figure in another village with no supply.