Randomized intervention study of solar disinfection of drinking water in the prevention of dysentery in Kenyan children aged under 5 years

Wilderness Medical Society Clinical Practice Guidelines on Water Treatment for Wilderness, International Travel, and Austere Situations: 2024 Update

To provide guidance to medical providers, wilderness users, and travelers, the Wilderness Medical Society convened an expert panel to develop evidence-based guidelines for treating water in situations where the potability of available water is not assured, including wilderness and international travel, areas impacted by disaster, and other areas without adequate sanitation. The guidelines present the available methods for reducing or eliminating microbiological contamination of water for individuals, groups, or households; evaluation of their effectiveness; and practical considerations. The evidence base includes both laboratory and clinical publications. The panel graded the recommendations based on the quality of supporting evidence and the balance between benefits and risks/burdens according to the criteria published by the American College of Chest Physicians.

Impact on childhood mortality of interventions to improve drinking water, sanitation, and hygiene (WASH) to households: Systematic review and meta-analysis

BACKGROUND

In low- and middle-income countries (L&MICs), the biggest contributing factors to the global burden of disease in childhood are deaths due to respiratory illness and diarrhoea, both of which are closely related to use of water, sanitation, and hygiene (WASH) services by households. However, current estimates of the health impacts of WASH interventions use self-reported morbidity, which may fail to capture longer-term or more severe impacts. Reported mortality is thought to be less prone to bias than other reported measures. This study aimed to answer the question: What are the impacts of WASH interventions on reported childhood mortality in L&MICs?

METHODS AND FINDINGS

We conducted a systematic review and meta-analysis, using a published protocol. Systematic searches of 11 academic databases and trial registries, plus organisational repositories, were undertaken to locate studies of WASH interventions, which were published in peer review journals or other sources (e.g., organisational reports and working papers). Intervention studies of WASH improvements implemented under endemic disease circumstances in L&MICs were eligible, which reported findings at any time until March 2020. We used the participant flow data supplied in response to journal editors' calls for greater transparency. Data were collected by two authors working independently. We included evidence from 24 randomized and 11 nonrandomized studies of WASH interventions from all global regions, incorporating 2,600 deaths. Effects of 48 WASH treatment arms were included in analysis. We critically appraised and synthesised evidence using meta-analysis to improve statistical power. We found WASH interventions are associated with a significant reduction of 17% in the odds of all-cause mortality in childhood (OR = 0.83, 95% CI = 0.74, 0.92, evidence from 38 interventions), and a significant reduction in diarrhoea mortality of 45% (OR = 0.55, 95% CI = 0.35, 0.84; 10 interventions). Further analysis by WASH technology indicated interventions providing improved water in quantity to households were most consistently associated with reductions in all-cause mortality. Community-wide sanitation was most consistently associated with reductions in diarrhoea mortality. Around one-half of the included studies were assessed as being at "moderate risk of bias" in attributing mortality in childhood to the WASH intervention, and no studies were found to be at "low risk of bias." The review should be updated to incorporate additional published and unpublished participant flow data.

CONCLUSIONS

The findings are congruent with theories of infectious disease transmission. Washing with water presents a barrier to respiratory illness and diarrhoea, which are the two biggest contributors to all-cause mortality in childhood in L&MICs. Community-wide sanitation halts the spread of diarrhoea. We observed that evidence synthesis can provide new findings, going beyond the underlying data from trials to generate crucial insights for policy. Transparent reporting in trials creates opportunities for research synthesis to answer questions about mortality, which individual studies of interventions cannot be reliably designed to address.

Solar water disinfection in large-volume containers: from the laboratory to the field. A case study in Tigray, Ethiopia

The lack of safe drinking water affects communities in low-to-medium-income countries most. This barrier can be overcome by using sustainable point-of-use water treatments. Solar energy has been used to disinfect water for decades, and several efforts have been made to optimise the standard procedure of solar water disinfection (SODIS process). However, the Health Impact Assessment of implementing advanced technologies in the field is also a critical step in evaluating the success of the optimisation. This work reports a sustainable scaling-up of SODIS from standard 2 L bottles to 25 L transparent jerrycans (TJC) and a 12-month field implementation in four sites of Tigray in Ethiopia, where 80.5% of the population lives without reliable access to safe drinking water and whose initial baseline average rate of diarrhoeal disease in children under 5 years was 13.5%. The UVA dose required for 3-log reduction of E. coli was always lower than the minimum UVA daily dose received in Tigray (9411 ± 55 Wh/m²). Results confirmed a similar decrease in cases of diarrhoea in children in the implementation (25 L PET TJC) and control (2 L PET bottles) groups, supporting the feasibility of increasing the volume of the SODIS water containers to produce safer drinking water with a sustainable and user-friendly process.

Epidemiological and Immunological Gains from Solar Water Disinfection (SODIS): Fact or Wishful Thinking?

OBJECTIVE

There is still no consensus on the impact of using solar disinfection (SODIS) to reduce the prevalence of waterborne gastrointestinal diseases. The reported reduction in diarrhea prevalence among SODIS users has been attributed to the consumption of water free of viable pathogens. However, it has also been suggested that ingestion of SODIS-inactivated pathogens may induce protective immunological changes that may also contribute to a reduction in the frequency of diarrhea. The present study aimed to critically review the epidemiological and immunological gains of using SODIS.

METHODS

We critically reviewed 22 articles published in English, selected from 2,118 records systematically retrieved from the databases.

RESULTS

All trials (except one) reported a significant reduction in diarrhea prevalence among children using SODIS, but some of the data from trials report contrary findings. All in vitro and in vivo assays indicate that SODIS-inactivated pathogenic bacteria have the potential to induce immunological alterations that may result in protective immunological effects. Studies with a low risk of bias are still awaited to confirm the ability of using SODIS to reduce the prevalence of diarrhea.

CONCLUSION

Reducing the prevalence of diarrhea depends on the success of SODIS delivery strategies in inducing behavioral changes in communities that result in the production of SODIS-compliant outcomes. The results of trials reporting a reduction in the prevalence of diarrhea due to the use of SODIS seem to support the hypothesis of the contribution of the protective immunological effect against diarrhea in SODIS users.

Influence of Maternal Exposure to Mass Media on Growth Stunting Among Children Under Five: Mediation Analysis Through the Water, Sanitation, and Hygiene Program

Background

The issue of malnutrition in the Democratic Republic of Congo is severe. Meanwhile, the Water, Sanitation, and Hygiene program has been demonstrated to be effective in reducing the rates of growth stunting among children.

Objective

We aimed to explore the association between maternal exposure to mass media and stunting in children through water, sanitation, and hygiene behaviors.

Methods

Mediation analysis was conducted using data from the 2018 Multiple Indicators Cluster Surveys.

Results

Mothers’ exposures to television and the internet in the Democratic Republic of Congo significantly decreases the risk of stunting in children by 5% and 10%, respectively, mediated by household water, sanitation, and hygiene facilities and practices.

Conclusions

These findings could inform interventions and policies to reduce the rate of stunting rate children by promoting water, sanitation, and hygiene through mass media, especially through the internet and television.

Water, sanitation and hygiene interventions and the prevention and treatment of childhood acute malnutrition: A systematic review

Undernutrition is more prevalent among children living in unsanitary environments with inadequate water, sanitation and hygiene (WASH). Despite good evidence for the effect of WASH on multiple infectious diseases, evidence for the effect of WASH interventions on childhood undernutrition is less well established, particularly for acute malnutrition. To assess the effectiveness of WASH interventions in preventing and treating acute childhood malnutrition, we performed electronic searches to identify relevant studies published between 1 January 2000 and 13 May 2019. We included studies assessing the effect of WASH on prevention and treatment of acute malnutrition in children under 5 years of age. Data were extracted by two independent reviewers. We included 26 articles of 599 identified references with a total of 43,083 participants. Twenty-five studies reported on the effect of WASH on prevention, and two studies reported its effect on treatment of acute malnutrition. Current evidence does not show consistent associations of WASH conditions and interventions with prevention of acute malnutrition or with the improvement of its treatment outcomes. Only two high-quality randomized controlled trials (RCTs) demonstrated that improved water quality during severe acute malnutrition treatment improved recovery outcomes but did not prevent relapse. Many of the interventions consisted of a package of WASH services, making impossible to attribute the effect to one specific component. This highlights the need for high-quality, rigorous intervention studies assessing the effects of WASH interventions specifically designed to prevent acute malnutrition or improve its treatment.

Interventions promoting uptake of water, sanitation and hygiene (WASH) technologies in low- and middle-income countries: An evidence and gap map of effectiveness studies

Background

Lack of access to and use of water, sanitation and hygiene (WASH) cause 1.6 million deaths every year, of which 1.2 million are due to gastrointestinal illnesses like diarrhoea and acute respiratory infections like pneumonia. Poor WASH access and use also diminish nutrition and educational attainment, and cause danger and stress for vulnerable populations, especially for women and girls. The hardest hit regions are sub-Saharan Africa and South Asia. Sustainable Development Goal (SDG) 6 calls for the end of open defecation, and universal access to safely managed water and sanitation facilities, and basic hand hygiene, by 2030. WASH access and use also underpin progress in other areas such as SDG1 poverty targets, SDG3 health and SDG4 education targets. Meeting the SDG equity agenda to "leave none behind" will require WASH providers prioritise the hardest to reach including those living remotely and people who are disadvantaged.

Objectives

Decision makers need access to high-quality evidence on what works in WASH promotion in different contexts, and for different groups of people, to reach the most disadvantaged populations and thereby achieve universal targets. The WASH evidence map is envisioned as a tool for commissioners and researchers to identify existing studies to fill synthesis gaps, as well as helping to prioritise new studies where there are gaps in knowledge. It also supports policymakers and practitioners to navigate the evidence base, including presenting critically appraised findings from existing systematic reviews.

Methods

This evidence map presents impact evaluations and systematic reviews from the WASH sector, organised according to the types of intervention mechanisms, WASH technologies promoted, and outcomes measured. It is based on a framework of intervention mechanisms (e.g., behaviour change triggering or microloans) and outcomes along the causal pathway, specifically behavioural outcomes (e.g., handwashing and food hygiene practices), ill-health outcomes (e.g., diarrhoeal morbidity and mortality), nutrition and socioeconomic outcomes (e.g., school absenteeism and household income). The map also provides filters to examine the evidence for a particular WASH technology (e.g., latrines), place of use (e.g., home, school or health facility), location (e.g., global region, country, rural and urban) and group (e.g., people living with disability). Systematic searches for published and unpublished literature and trial registries were conducted of studies in low- and middle-income countries (LMICs). Searches were conducted in March 2018, and searches for completed trials were done in May 2020. Coding of information for the map was done by two authors working independently. Impact evaluations were critically appraised according to methods of conduct and reporting. Systematic reviews were critically appraised using a new approach to assess theory-based, mixed-methods evidence synthesis.

Results

There has been an enormous growth in impact evaluations and systematic reviews of WASH interventions since the International Year of Sanitation, 2008. There are now at least 367 completed or ongoing rigorous impact evaluations in LMICs, nearly three-quarters of which have been conducted since 2008, plus 43 systematic reviews. Studies have been done in 83 LMICs, with a high concentration in Bangladesh, India, and Kenya. WASH sector programming has increasingly shifted in focus from what technology to supply (e.g., a handwashing station or child's potty), to the best way in which to do so to promote demand. Research also covers a broader set of intervention mechanisms. For example, there has been increased interest in behaviour change communication using psychosocial "triggering", such as social marketing and community-led total sanitation. These studies report primarily on behavioural outcomes. With the advent of large-scale funding, in particular by the Bill & Melinda Gates Foundation, there has been a substantial increase in the number of studies on sanitation technologies, particularly latrines. Sustaining behaviour is fundamental for sustaining health and other quality of life improvements. However, few studies have been done of intervention mechanisms for, or measuring outcomes on sustained adoption of latrines to stop open defaecation. There has also been some increase in the number of studies looking at outcomes and interventions that disproportionately affect women and girls, who quite literally carry most of the burden of poor water and sanitation access. However, most studies do not report sex disaggregated outcomes, let alone integrate gender analysis into their framework. Other vulnerable populations are even less addressed; no studies eligible for inclusion in the map were done of interventions targeting, or reporting on outcomes for, people living with disabilities. We were only able to find a single controlled evaluation of WASH interventions in a health care facility, in spite of the importance of WASH in health facilities in global policy debates. The quality of impact evaluations has improved, such as the use of controlled designs as standard, attention to addressing reporting biases, and adequate cluster sample size. However, there remain important concerns about quality of reporting. The quality and usefulness of systematic reviews for policy is also improving, which draw clearer distinctions between intervention mechanisms and synthesise the evidence on outcomes along the causal pathway. Adopting mixed-methods approaches also provides information for programmes on barriers and enablers affecting implementation.

Conclusion

Ensuring everyone has access to appropriate water, sanitation, and hygiene facilities is one of the most fundamental of challenges for poverty elimination. Researchers and funders need to consider carefully where there is the need for new primary evidence, and new syntheses of that evidence. This study suggests the following priority areas:Impact evaluations incorporating understudied outcomes, such as sustainability and slippage, of WASH provision in understudied places of use, such as health care facilities, and of interventions targeting, or presenting disaggregated data for, vulnerable populations, particularly over the life-course and for people living with a disability;Improved reporting in impact evaluations, including presentation of participant flow diagrams; andSynthesis studies and updates in areas with sufficient existing and planned impact evaluations, such as for diarrhoea mortality, ARIs, WASH in schools and decentralisation. These studies will preferably be conducted as mixed-methods systematic reviews that are able to answer questions about programme targeting, implementation, effectiveness and cost-effectiveness, and compare alternative intervention mechanisms to achieve and sustain outcomes in particular contexts, preferably using network meta-analysis.

Narrative Review of Primary Preventive Interventions against Water-Borne Diseases: Scientific Evidence of Health-EDRM in Contexts with Inadequate Safe Drinking Water

Waterborne diseases account for 1.5 million deaths a year globally, particularly affecting children in low-income households in subtropical areas. It is one of the most enduring and economically devastating biological hazards in our society today. The World Health Organization Health Emergency and Disaster Risk Management (health-EDRM) Framework highlights the importance of primary prevention against biological hazards across all levels of society. The framework encourages multi-sectoral coordination and lessons sharing for community risk resilience. A narrative review, conducted in March 2021, identified 88 English-language articles published between January 2000 and March 2021 examining water, sanitation, and hygiene primary prevention interventions against waterborne diseases in resource-poor settings. The literature identified eight main interventions implemented at personal, household and community levels. The strength of evidence, the enabling factors, barriers, co-benefits, and alternative measures were reviewed for each intervention. There is an array of evidence available across each intervention, with strong evidence supporting the effectiveness of water treatment and safe household water storage. Studies show that at personal and household levels, interventions are effective when applied together. Furthermore, water and waste management will have a compounding impact on vector-borne diseases. Mitigation against waterborne diseases require coordinated, multi-sectoral governance, such as building sanitation infrastructure and streamlined waste management. The review showed research gaps relating to evidence-based alternative interventions for resource-poor settings and showed discrepancies in definitions of various interventions amongst research institutions, creating challenges in the direct comparison of results across studies.

Distance to water source in early childhood affects growth: a cohort study

OBJECTIVES

Approximately 165 million children aged <5 years are at risk of low height-for-age. This study explored whether water quality and distance to water source affected short- and long-term growth, and the critical time windows of such effects.

STUDY DESIGN

This study used data from the China Health and Nutrition Survey (CHNS), which was a cohort study performed in 15 Chinese provinces.

METHODS

Data from the CHNS between 1989 and 2011 were examined. Three cohorts of children who were enrolled at 0-2 years of age in 1989, 1993, and 2000 provided sufficient data for this study. Child height was measured by physicians, and household water supply, including the water quality (safe or unsafe) and distance to the source (in-yard or out-yard), was assessed using a questionnaire when the children were 0-2, 4-6, and 11-13 years of age. Multiple regressions were performed to analyse the associations between water quality and distance to the source at various ages, and height at that age and older ages, with and without adjusting for the household water supply at previous ages. Multiple informant models were created using a generalised estimating equation and these were used to assess whether the exposure coefficients were equal across the three age periods.

RESULTS

A total of 1192 children were included. Water quality was not significantly associated with height over the three age periods. An out-yard water source at the age of 0-2 years was not associated with child height at that age, but it was inversely associated with child height at ages 4-6 and 11-13 years (β = -1.605, 95% confidence interval [CI]: -2.490 to -0.720, and β = -2.817, 95% CI: -4.411 to -1.224, respectively), after adjusting for sociodemographic and economic covariates and baseline child height. Distance to the water source at age 4-6 and 11-13 years was not significantly associated with height. However, significant differences were observed in the associations between distance to water source across the three age periods and height at age 4-6 and 11-13 years (p_int = 0.064 and 0.069, respectively).

CONCLUSIONS

Distance to the water source in early, but not later, childhood exerted a long-term effect on child height. When the water quality is good, efforts should be made to shorten the distance to the source to improve child health and growth.

Effectiveness of solar disinfection water treatment method for reducing childhood diarrhoea: a systematic review and meta-analysis

OBJECTIVE

This study aimed to pool out the available evidence on the effectiveness of the solar disinfection water treatment method for reducing childhood diarrhoea.

DESIGN

Systematic review and meta-analysis.

SETTING

Global.

METHODS

Searches were conducted in Medline/PubMed, Scopus, Google Scholar, Cochrane Library databases and references to other studies. The review included all children living anywhere in the world regardless of sex, ethnicity and socioeconomic status published in English until December 2019. Studies that compared the diarrhoea incidence between the intervention group who were exposed to solar disinfection water treatment and the control group who were not exposed to such water treatment were included. The outcome of interest was the change in observed diarrhoea incidence and the risk from baseline to postintervention. Two independent reviewers critically appraised the selected studies. Effect sizes were expressed as risk ratios, and their 95% CIs were calculated for analysis.

RESULTS

We identified 10 eligible studies conducted in Africa, Latin America and Asia that included 5795 children aged from 1 to 15 years. In all identified studies, solar disinfection reduced the risk of diarrhoea in children, and the effect was statistically significant in eight of the studies. The estimated pooled risk ratio of childhood diarrhoea among participants that used the solar disinfection water treatment method was 0.62 (95% CI 0.53 to 0.72). The overall pooled results indicated that the intervention of solar disinfection water treatment had reduced the risk of childhood diarrhoea by 38%.

CONCLUSIONS

The intervention of solar disinfection water treatment significantly reduced the risk of childhood diarrhoea. However, the risk of bias and marked heterogeneity of the included studies precluded definitive conclusions. Further high-quality studies are needed to determine whether solar disinfection water treatment is an important method to reduce childhood diarrhoea.

PROSPERO REGISTRATION NUMBER

CRD42020159243.

A Transdisciplinary Methodology for Introducing Solar Water Disinfection to Rural Communities in Malawi-Formative Research Findings

Despite the increasing volume of evidence demonstrating the efficacy of solar water disinfection (SODIS) as a household water treatment technology, there still appear to be significant barriers to uptake in developing countries. The potential of SODIS is often treated with skepticism in terms of effective treatment, volume, and safety, and is dismissed in preference for more accepted technologies such as ceramic filters and dose chlorination. As part of WATERSPOUTT (EU H2020 688928), our study used a transdisciplinary methodology to cocreate an innovative SODIS system in rural Malawi. The formative work focused on the design of 1) an appropriate and acceptable system and 2) a context-specific intervention delivery program using a behavior-centered design. Initial research identified specific water needs and challenges, which were discussed along with a cocreation process with potential end users, through a series of shared dialogue workshops (SDWs). Specifications from end users outlined a desire for higher volume systems (20 L) that were "familiar" and could be manufactured locally. Development of the "SODIS bucket" was then undertaken by design experts and local manufacturers, with input from end users and subject to controlled testing to ensure efficacy and safety. Concurrent data were collated using questionnaires (n = 777 households), water point mapping (n = 121), water quality testing (n = 46), and behavior change modeling (n = 100 households). These identified specific contextual issues (hydrogeology, water access, gender roles, social capital, and socioeconomic status), and behavioral determinants (normative, ability, and self-regulation factors) that informed the development and delivery mechanism for the implementation toolkit. Integr Environ Assess Manag 2020;16:871-884. © 2020 The Authors. Integrated Environmental Assessment and Management published by Wiley Periodicals, Inc. on behalf of Society of Environmental Toxicology & Chemistry (SETAC).

Effect of water, sanitation and hygiene interventions alone and combined with nutrition on child growth in low and middle income countries: a systematic review and meta-analysis

OBJECTIVE

This study aimed to provide clarification on the benefits of water, sanitation and hygiene (WASH) alone separately and combined with nutrition in improving child growth outcomes.

DESIGN

Systematic review and meta-analysis.

METHODS

We conducted a systematic review using the Preferred Reporting Items for Systematic Review and Meta-Analyses guidelines. PubMed, MEDLINE, EMBASE, Scopus, Cochrane Library, Web of Science and Science Direct were searched in May 2018 and last updated in April 2019. We included studies that reported WASH interventions alone separately or combined with nutrition. Fixed and random-effects models were used to estimate pooled effect in mean difference (MD). Heterogeneity and publication bias statistics were performed.

RESULTS

A total of 18 studies were included: 13 cluster randomised controlled trials (RCTs) and 5 non-randomised controlled trials (non-RCTs). Non-RCTs showed effect of WASH interventions alone on height-for-age z-score (HAZ) (MD=0.14; 95% CI 0.08 to 0.21) but RCTs did not. WASH alone of non-RCTs and RCTs that were delivered over 18-60 months indicated an effect on HAZ (MD=0.04; 95% CI 0.01 to 0.08). RCTs showed an effect for children <2 years (MD=0.07; 95% CI 0.01 to 0.13). Non-RCTs of WASH alone and those that included at least two components, improved HAZ (MD=0.15; 95% CI 0.07 to 0.23) but RCTs did not. WASH alone of non-RCTs and RCTs separately or together showed no effect on weight-for-age z-score (WAZ) and weight-for-height z-score (WHZ). Combined WASH with nutrition showed an effect on HAZ (MD=0.13; 95% CI 0.08 to 0.17) and on WAZ (MD=0.09; 95% CI 0.05 to 0.13) and was borderline on WHZ.

CONCLUSIONS

WASH interventions alone improved HAZ when delivered over 18-60 months and for children <2 years. Combined WASH with nutrition showed a strong effect on HAZ and WAZ and a borderline effect on WHZ. Integrated WASH with nutrition interventions may be effective inimproving child growth outcomes.

Wilderness Medical Society Clinical Practice Guidelines for Water Disinfection for Wilderness, International Travel, and Austere Situations

To provide guidance to clinicians, the Wilderness Medical Society convened experts to develop evidence-based guidelines for water disinfection in situations where the potability of available water is not ensured, including wilderness and international travel, areas affected by disaster, and other areas without adequate sanitation. The guidelines present the available methods for reducing or eliminating microbiologic contamination of water for individuals, groups, or households; evaluation of their effectiveness; and practical considerations. The evidence evaluation includes both laboratory and clinical publications. The panel graded the recommendations based on the quality of supporting evidence and the balance between benefits and risks or burdens, according to the criteria published by the American College of Chest Physicians.

21st century research in urban WASH and health in sub-Saharan Africa: methods and outcomes in transition

Tackling global inequalities in access to Water, Sanitation and Hygiene (WASH) remains an urgent issue - 58% of annual diarrhoeal deaths are caused by inadequate WASH provision. A global context of increasing urbanisation, changing demographics and health transitions demands an understanding and impact of WASH on a broad set of health outcomes. We examine the literature, in terms of health outcomes, considering WASH access and interventions in urban sub-Saharan Africa from 2000 to 2017. Our review of studies which evaluate the effectiveness of specific WASH interventions, reveals an emphasis of WASH research on acute communicable diseases, particularly diarrhoeal diseases. In contrast, chronic communicable and non-communicable health outcomes were notable gaps in the literature as well as a lack of focus on cross-cutting issues, such as ageing, well-being and gender equality. We recommend a broader focus of WASH research and interventions in urban Africa to better reflect the demographic and health transitions happening. Abbreviations: CBA: Controlled Before and After; GSD: Government Service Delivery; IWDSSD: International Drinking-Water, Supply and Sanitation Decade (IDWSSD); KAP: Knowledge, Attitudes and Practices; IBD: Irritable Bowel Diseases; MDG: Millennium Development Goals; NTD: Neglected Tropical Diseases; PSSD: Private Sector Service Delivery; SDG: Sustainable Development Goals; SSA: Sub Saharan Africa; SODIS: Solar Disinfection System; STH: Soil Transmitted Helminths; RCT: Randomised Control Trial; WASH: Water Sanitation and Hygiene; WHO: World Health Organization.

Ozone and Photocatalytic Processes for Pathogens Removal from Water: A Review

The search for alternative water sources is pushing to the reuse of treated water coming from municipal wastewater treatment plants. However, this requires that tightened standards be fulfilled. Among them is the microbiological safety of reused water. Although chlorination is the mostly applied disinfection system, it presents several disadvantages, such as the high doses required and the possibility of formation of dangerous by-products. Moreover, the threat of antibiotic resistance genes (ARGs) spread throughout poorly treated water is requiring the implementation of more efficient disinfection systems. Ozone and photo assisted disinfection technologies are being given special attention to reach treated water with higher quality. Still, much must be done to optimize the processes so that cost-effective systems may be obtained. This review paper gives a critical overview on the application of ozone and photo-based disinfection systems, bearing in mind their advantages and disadvantages when applied to water and municipal wastewater. Also, the possibility of integrated disinfection systems is considered.

The effect of SODIS water treatment intervention at the household level in reducing diarrheal incidence among children under 5 years of age: a cluster randomized controlled trial in Dabat district, northwest Ethiopia

BACKGROUND

Solar Disinfection (SODIS) of water is an economical, user-friendly, and environmentally safe household water treatment method that has been advocated as a means of decreasing the burden of diarrhea among children under 5 years of age. Laboratory studies have consistently shown the efficacy of the SODIS method to destroy waterborne pathogens. However, the evidence-based health effect of a SODIS intervention at the household level is limited. The main aim of the study was to examine the effectiveness of a SODIS intervention in reducing the incidence of diarrhea among under-five children.

METHODS

A community-based, cluster randomized controlled trial was conducted, over 6 months from 10 January to 7 July 2016, in 28 rural villages of northwest Ethiopia. In the intervention group, 384 children in 279 households received polyethylene terephthalate (PET) bottles, and in the control group 394 children in 289 households who continued to use their usual drinking-water sources were included in the trial. The study compared diarrheal incidence among the intervention group children who were exposed to SODIS household water treatment and the control group children who were not exposed to such water treatment. A generalized estimating equation (GEE) model was used to compute the adjusted incidence rate ratio and the corresponding 95% confidence interval.

RESULTS

In this trial, the overall SODIS compliance was 90.6%. The incidence of diarrhea was 8.3 episodes/100 person-week observations in the intervention group compared to 15.3 episodes/100 person-week observations in the control group. A statistically significant reduction was observed in the incidence of diarrhea in the intervention group compared to the control (adjusted IRR 0.60 (95% CI 0.52, 0.70) with a corresponding prevention of 40% (95% CI: 34, 48).

CONCLUSION

The SODIS intervention substantially reduced the incidence of diarrhea among under-five children in a rural community of northwest Ethiopia. This indicates that a SODIS intervention is an invaluable strategy that needs to be integrated with the National Health Extension Program to be addressed to rural communities.

TRIAL REGISTRATION

Clinical Trial Registry India, ID: CTRI/2017/09/009640 . Registered retrospectively on 5 September 2017.

Improving household air, drinking water and hygiene in rural Peru: a community-randomized-controlled trial of an integrated environmental home-based intervention package to improve child health

Background

Diarrhoea and acute lower respiratory infections are leading causes of childhood morbidity and mortality, which can be prevented by simple low-cost interventions. Integrated strategies can provide additional benefits by addressing multiple health burdens simultaneously.

Methods

We conducted a community-randomized-controlled trial in 51 rural communities in Peru to evaluate whether an environmental home-based intervention package, consisting of improved solid-fuel stoves, kitchen sinks, solar disinfection of drinking water and hygiene promotion, reduces lower respiratory infections, diarrhoeal disease and improves growth in children younger than 36 months. The attention control group received an early child stimulation programme.

Results

We recorded 24 647 child-days of observation from 250 households in the intervention and 253 in the attention control group during 12-month follow-up. Mean diarrhoea incidence was 2.8 episodes per child-year in the intervention compared with 3.1 episodes in the control arm. This corresponds to a relative rate of 0.78 [95% confidence interval (CI): 0.58-1.05] for diarrhoea incidence and an odds ratio of 0.71 (95% CI: 0.47-1.06) for diarrhoea prevalence. No effects on acute lower respiratory infections or children's growth rates were observed.

Conclusions

Combined home-based environmental interventions slightly reduced childhood diarrhoea, but the confidence interval included unity. Effects on growth and respiratory outcomes were not observed, despite high user compliance of the interventions. The absent effect on respiratory health might be due to insufficient household air quality improvements of the improved stoves and additional time needed to achieve attitudinal and behaviour change when providing composite interventions.

Water, sanitation and hygiene interventions for acute childhood diarrhea: a systematic review to provide estimates for the Lives Saved Tool

Background

In the Sustainable Development Goals (SDGs) era, there is growing recognition of the responsibilities of non-health sectors in improving the health of children. Interventions to improve access to clean water, sanitation facilities, and hygiene behaviours (WASH) represent key opportunities to improve child health and well-being by preventing the spread of infectious diseases and improving nutritional status.

Methods

We conducted a systematic review of studies evaluating the effects of WASH interventions on childhood diarrhea in children 0–5 years old. Searches were run up to September 2016. We screened the titles and abstracts of retrieved articles, followed by screening of the full-text reports of relevant studies. We abstracted study characteristics and quantitative data, and assessed study quality. Meta-analyses were performed for similar intervention and outcome pairs.

Results

Pooled analyses showed diarrhea risk reductions from the following interventions: point-of-use water filtration (pooled risk ratio (RR): 0.47, 95% confidence interval (CI): 0.36–0.62), point-of-use water disinfection (pooled RR: 0.69, 95% CI: 0.60–0.79), and hygiene education with soap provision (pooled RR: 0.73, 95% CI: 0.57–0.94). Quality ratings were low or very low for most studies, and heterogeneity was high in pooled analyses. Improvements to the water supply and water disinfection at source did not show significant effects on diarrhea risk, nor did the one eligible study examining the effect of latrine construction.

Conclusions

Various WASH interventions show diarrhea risk reductions between 27% and 53% in children 0–5 years old, depending on intervention type, providing ample evidence to support the scale-up of WASH in low and middle-income countries (LMICs). Due to the overall low quality of the evidence and high heterogeneity, further research is required to accurately estimate the magnitude of the effects of these interventions in different contexts.

Effects of Boiling Drinking Water on Diarrhea and Pathogen-Specific Infections in Low- and Middle-Income Countries: A Systematic Review and Meta-Analysis

Globally, approximately 2 billion people lack microbiologically safe drinking water. Boiling is the most prevalent household water treatment method, yet evidence of its health impact is limited. To conduct this systematic review, we searched four online databases with no limitations on language or publication date. Studies were eligible if health outcomes were measured for participants who reported consuming boiled and untreated water. We used reported and calculated odds ratios (ORs) and random-effects meta-analysis to estimate pathogen-specific and pooled effects by organism group and nonspecific diarrhea. Heterogeneity and publication bias were assessed using I2, meta-regression, and funnel plots; study quality was also assessed. Of the 1,998 records identified, 27 met inclusion criteria and reported extractable data. We found evidence of a significant protective effect of boiling for Vibrio cholerae infections (OR = 0.31, 95% confidence interval [CI] = 0.13-0.79, N = 4 studies), Blastocystis (OR = 0.35, 95% CI = 0.17-0.69, N = 3), protozoal infections overall (pooled OR = 0.61, 95% CI = 0.43-0.86, N = 11), viral infections overall (pooled OR = 0.83, 95% CI = 0.7-0.98, N = 4), and nonspecific diarrheal outcomes (OR = 0.58, 95% CI = 0.45-0.77, N = 7). We found no evidence of a protective effect for helminthic infections. Although our study was limited by the use of self-reported boiling and non-experimental designs, the evidence suggests that boiling provides measureable health benefits for pathogens whose transmission routes are primarily water based. Consequently, we believe a randomized controlled trial of boiling adherence and health outcomes is needed.

Can water, sanitation and hygiene help eliminate stunting? Current evidence and policy implications

Stunting is a complex and enduring challenge with far‐reaching consequences for those affected and society as a whole. To accelerate progress in eliminating stunting, broader efforts are needed that reach beyond the nutrition sector to tackle the underlying determinants of undernutrition. There is growing interest in how water, sanitation and hygiene (WASH) interventions might support strategies to reduce stunting in high‐burden settings, such as South Asia and sub‐Saharan Africa. This review article considers two broad questions: (1) can WASH interventions make a significant contribution to reducing the global prevalence of childhood stunting, and (2) how can WASH interventions be delivered to optimize their effect on stunting and accelerate progress? The evidence reviewed suggests that poor WASH conditions have a significant detrimental effect on child growth and development resulting from sustained exposure to enteric pathogens but also due to wider social and economic mechanisms. Realizing the potential of WASH to reduce stunting requires a redoubling of efforts to achieve universal access to these services as envisaged under the Sustainable Development Goals. It may also require new or modified WASH strategies that go beyond the scope of traditional interventions to specifically address exposure pathways in the first 2 years of life when the process of stunting is concentrated.

Examining the relationship between socio-economic status, WASH practices and wasting

Childhood wasting is a global problem and is significantly more pronounced in low and middle income countries like Bangladesh. Socio Economic Status (SES) and Water, Sanitation and Hygiene (WASH) practices may be significantly associated with wasting. Most previous research is consistent about the role of SES, but the significance of WASH in the context of wasting remains ambiguous. The effect of SES and WASH on weight for length (WHZ) is examined using a Structural Equation Model (SEM) to explicitly describe the direct and indirect role of WASH in the context of SES.A nationally representative survey of 10,478 Bangladeshi children under 5 were examined. An expert defined SEM was used to construct latent variables for SES and WASH. The SEM included a direct pathway from SES to WHZ and an indirect pathway from SES to WHZ via WASH along with regression of relevant covariates on the outcome WHZ and the latent variables. Both SES (p<0.01) and WASH (p<0.05) significantly affect WHZ. SES (p<0.01) also significantly affects WASH. Other structural components showed that child's age (p<0.01) affects WHZ and types of residence (p<0.01) affects SES. WASH practices at least partially mediate the association between SES and wasting status. WASH and SES are both significantly associated with WHZ.

Assessing the Health Impact of Water Quality Interventions in Low-Income Settings: Concerns Associated with Blinded Trials and the Need for Objective Outcomes

BACKGROUND

A dramatic disparity between the results of blinded versus open trial designs has raised questions about the effectiveness of water quality interventions and other environmental interventions to prevent diarrhea, a leading killer of young children in low-income countries.

OBJECTIVES

We summarize the results of blinded versus open trials of water quality interventions, describe evidence from a recent placebo-controlled trial in India suggesting that control households were put at risk from their participation, and suggest alternatives to blinded trials that could resolve continued uncertainty about the magnitude of the protective effect of water, sanitation, and hygiene (WASH) interventions without presenting ethical questions.

DISCUSSION

Concerns about reporting bias in open trial designs continue to cause uncertainty about the effectiveness of WASH interventions. However, evidence suggests that despite instructions to the contrary, placebos may encourage control group participants in blinded trials to cease practicing traditional water treatment practices in the mistaken belief that they are protected by an active intervention. Although objective outcomes such as pathogen incrimination, seroconversion, biomarkers, and anthropometry can be helpful, these are often costly, nonspecific, and unsuitable for evaluating programmatic interventions.

CONCLUSIONS

Unless researchers can be assured that a placebo will not cause those in a control group to change their behavior in a manner that increases their risk, it is incumbent on researchers to use alternatives. Validated objective measures are needed for assessing the health impact of WASH interventions that are reliable, affordable, and suitable both for research and program evaluation.

CITATION

Clasen T, Boisson S. 2016. Assessing the health impact of water quality interventions in low-income settings: concerns associated with blinded trials and the need for objective outcomes. Environ Health Perspect 124:886-889; http://dx.doi.org/10.1289/ehp.1510532.

Effectiveness of solar disinfection (SODIS) in rural coastal Bangladesh

Scarcity of drinking water in the coastal area of Bangladesh compels the inhabitants to be highly dependent on alternative water supply options like rainwater harvesting system (RWHS), pond sand filter (PSF), and rain-feed ponds. Susceptibility of these alternative water supply options to microbial contamination demands a low-cost water treatment technology. This study evaluates the effectiveness of solar disinfection (SODIS) to treat drinking water from available sources in the southwest coastal area of Bangladesh. A total of 50 households from Dacope upazila in Khulna district were selected to investigate the performance of SODIS. Data were collected in two rounds to examine fecal coliform (FC) and Escherichia coli (E. coli) contamination of drinking water at the household water storage containers and SODIS bottles, and thereby determined the effectiveness of SODIS in reducing fecal contamination. All water samples were analyzed for pH, electrical conductivity, turbidity and salinity. SODIS significantly reduced FC and E. coli contamination under household conditions. The median health risk reduction by SODIS was more than 96 and 90% for pond and RWHS, respectively. Besides, turbidity of the treated water was found to be less than 5 NTU, except pond water. Only 34% of the participating households routinely adopted SODIS during the study.

Solar light (hv) and H2O2/hv photo-disinfection of natural alkaline water (pH 8.6) in a compound parabolic collector at different day periods in Sahelian region

The photo-disinfection of natural alkaline surface water (pH 8.6 ± 0.3) for drinking purposes was carried out under solar radiation treatments. The enteric bacteria studied were the wild total coliforms/Escherichia coli (10(4) CFU/ml) and Salmonella spp. (10(4) CFU/ml) naturally present in the water. The photo-disinfection of a 25-l water sample was carried out in a solar compound parabolic collector (CPC) in the absence and in the presence of hydrogen peroxide (H2O2). The addition of H2O2 (10 mg/L) to the sample water was sufficient to enhance the photo-disinfection and ensure an irreversible lethal action on the wild enteric bacteria contents of the sample. The inactivation kinetic of the system was significantly enhanced compared to the one carried out without H2O2 addition. The effect of the solar radiation parameters on the efficiency of the photo-disinfection were assessed. The pH has increased during the treatment in all the photo-disinfection processes (hv and H2O2/hv). The Salmonella spp strain has shown the best effective inactivate time in alkaline water than the one recorded under acidic or near-neutral conditions. The evolution of some physico-chemical parameters of the water (turbidity, NO2(-), NO3(-), NH4(+), HPO4(2-), and bicarbonate (HCO3(-))) was monitored during the treatment. Finally, the possible mechanistic process involved during the enteric bacteria inactivation was suggested.

Interventions to improve water quality for preventing diarrhoea

BACKGROUND

Diarrhoea is a major cause of death and disease, especially among young children in low-income countries. In these settings, many infectious agents associated with diarrhoea are spread through water contaminated with faeces.In remote and low-income settings, source-based water quality improvement includes providing protected groundwater (springs, wells, and bore holes), or harvested rainwater as an alternative to surface sources (rivers and lakes). Point-of-use water quality improvement interventions include boiling, chlorination, flocculation, filtration, or solar disinfection, mainly conducted at home.

OBJECTIVES

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

SEARCH METHODS

We searched the Cochrane Infectious Diseases Group Specialized Register (11 November 2014), CENTRAL (the Cochrane Library, 7 November 2014), MEDLINE (1966 to 10 November 2014), EMBASE (1974 to 10 November 2014), and LILACS (1982 to 7 November 2014). We also handsearched relevant conference proceedings, contacted researchers and organizations working in the field, and checked references from identified studies through 11 November 2014.

SELECTION CRITERIA

Randomized controlled trials (RCTs), quasi-RCTs, and controlled before-and-after studies (CBA) comparing interventions aimed at improving the microbiological quality of drinking water with no intervention in children and adults.

DATA COLLECTION AND ANALYSIS

Two review 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. We assessed the quality of evidence using the GRADE approach.

MAIN RESULTS

Forty-five cluster-RCTs, two quasi-RCTs, and eight CBA studies, including over 84,000 participants, met the inclusion criteria. Most included studies were conducted in low- or middle-income countries (LMICs) (50 studies) with unimproved water sources (30 studies) and unimproved or unclear sanitation (34 studies). The primary outcome in most studies was self-reported diarrhoea, which is at high risk of bias due to the lack of blinding in over 80% of the included studies. Source-based water quality improvementsThere is currently insufficient evidence to know if source-based improvements such as protected wells, communal tap stands, or chlorination/filtration of community sources consistently reduce diarrhoea (one cluster-RCT, five CBA studies, very low quality evidence). We found no studies evaluating reliable piped-in water supplies delivered to households. Point-of-use water quality interventionsOn average, distributing water disinfection products for use at the household level may reduce diarrhoea by around one quarter (Home chlorination products: RR 0.77, 95% CI 0.65 to 0.91; 14 trials, 30,746 participants, low quality evidence; flocculation and disinfection sachets: RR 0.69, 95% CI 0.58 to 0.82, four trials, 11,788 participants, moderate quality evidence). However, there was substantial heterogeneity in the size of the effect estimates between individual studies.Point-of-use filtration systems probably reduce diarrhoea by around a half (RR 0.48, 95% CI 0.38 to 0.59, 18 trials, 15,582 participants, moderate quality evidence). Important reductions in diarrhoea episodes were shown with ceramic filters, biosand systems and LifeStraw® filters; (Ceramic: RR 0.39, 95% CI 0.28 to 0.53; eight trials, 5763 participants, moderate quality evidence; Biosand: RR 0.47, 95% CI 0.39 to 0.57; four trials, 5504 participants, moderate quality evidence; LifeStraw®: RR 0.69, 95% CI 0.51 to 0.93; three trials, 3259 participants, low quality evidence). Plumbed in filters have only been evaluated in high-income settings (RR 0.81, 95% CI 0.71 to 0.94, three trials, 1056 participants, fixed effects model).In low-income settings, solar water disinfection (SODIS) by distribution of plastic bottles with instructions to leave filled bottles in direct sunlight for at least six hours before drinking probably reduces diarrhoea by around a third (RR 0.62, 95% CI 0.42 to 0.94; four trials, 3460 participants, moderate quality evidence).In subgroup analyses, larger effects were seen in trials with higher adherence, and trials that provided a safe storage container. In most cases, the reduction in diarrhoea shown in the studies was evident in settings with improved and unimproved water sources and sanitation.

AUTHORS' CONCLUSIONS

Interventions that address the microbial contamination of water at the point-of-use may be important interim measures to improve drinking water quality until homes can be reached with safe, reliable, piped-in water connections. The average estimates of effect for each individual point-of-use intervention generally show important effects. Comparisons between these estimates do not provide evidence of superiority of one intervention over another, as such comparisons are confounded by the study setting, design, and population.Further studies assessing the effects of household connections and chlorination at the point of delivery will help improve our knowledge base. As evidence suggests effectiveness improves with adherence, studies assessing programmatic approaches to optimising coverage and long-term utilization of these interventions among vulnerable populations could also help strategies to improve health outcomes.

A longitudinal study of long-term change in contamination hazards and shallow well quality in two neighbourhoods of Kisumu, Kenya

Sub-Saharan Africa is experiencing rapid urbanisation and many urban residents use groundwater where piped supplies are intermittent or unavailable. This study aimed to investigate long-term changes in groundwater contamination hazards and hand-dug well water quality in two informal settlements in Kisumu city, Kenya. Buildings, pit latrines, and wells were mapped in 1999 and 2013-2014. Sanitary risk inspection and water quality testing were conducted at 51 hand-dug wells in 2002 to 2004 and 2014. Pit latrine density increased between 1999 and 2014, whilst sanitary risk scores for wells increased between 2002 to 2004 and 2014 (n = 37, Z = -1.98, p = 0.048). Nitrate levels dropped from 2004 to 2014 (n = 14, Z = -3.296, p = 0.001), but multivariate analysis suggested high rainfall in 2004 could account for this. Thermotolerant coliform counts dropped between 2004 and 2014, with this reduction significant in one settlement. Hand-dug wells had thus remained an important source of domestic water between 1999 and 2014, but contamination risks increased over this period. Water quality trends were complex, but nitrate levels were related to both sanitary risks and rainfall. Given widespread groundwater use by the urban poor in sub-Saharan Africa, the study protocol could be further refined to monitor contamination in hand-dug wells in similar settings.

The effect of pyrite on Escherichia coli in water: proof-of-concept for the elimination of waterborne bacteria by reactive minerals

We present proof-of-concept results for the elimination of waterborne bacteria by reactive minerals. We exposed Escherichia coli MG1655 suspended in water to the reactive mineral pyrite (FeS₂) at room temperature and ambient light. This slurry eliminates 99.9% of bacteria in fewer than 4 hours. We also exposed Escherichia coli to pyrite leachate (supernatant liquid from slurry after 24 hours), which eliminates 99.99% of bacteria over the same time-scale. Unlike SOlar water DISinfection (SODIS), our results do not depend on the presence of ultraviolet (UV) light. We confirmed this by testing proposed SODIS additive and known photo-catalyst anatase (TiO₂) for antibacterial properties and found that, in contrast to pyrite, it does not eliminate E. coli under our experimental conditions. Previous investigations of naturally antibiotic minerals have focused on the medical applications of antibiotic clays, and thus have not been conducted under experimental conditions resembling those found in water purification. In our examination of the relevant literature, we have not found previously reported evidence for the use of reactive minerals in water sanitization. The results from this proof-of-concept experiment may have important implications for future directions in household water purification research.

Evaluation of the efficiency of the photo Fenton disinfection of natural drinking water source during the rainy season in the Sahelian region

The photo-disinfection of water from two different wells (W1, pH: 4.6-5.1 ± 0.02) and (W2 pH: 5.6-5.7 ± 0.02) was carried out during the rainy season at Ouagadougou-Burkina Faso, West Africa. The weather variation during the rainy season significantly affects the photo-disinfection processes (solar disinfection and photo-Fenton). The dilution of the water by rainwater highly affected the chemical composition of the wells' water used in this study; very low iron contents Compared to the ones recorded during the dry season were recorded in all water samples. Both photo-disinfection processes were used to treat 25 L of water in a compound parabolic collector (CPC). None of them have shown the total inactivation of both wild enteric bacteria strains (total coliforms/E. coli and Salmonella spp.) involved in the treatment. However, the total coliforms/E. coli strains were totally inactivated during the exposure under most of the photo-Fenton treatment. Also, the remaining strains, especially those of Salmonella spp. were achieved during the subsequent 24h of dark storage under the action of the Fenton process. Under uniquely solar radiation, total inactivation was recorded only in the total coliforms/E. coli strains. The impact of the available irradiance on the efficiency of the photo-Fenton disinfection of natural water was highlighted during the exposure under high intermittent solar radiation. The impact of the HCO3(-) concentration of both wells' water on the evolution of the pH during the photo-disinfection was recorded. Drastic decrease was noticed after the initial fast increase in presence of low HCO3(-) concentration while a steady state was observed after the increase in presence of higher concentration. The redox activities of the nitrogen components of the water during both photo-disinfection processes have led to increased concentration of nitrite in all the cases and variations were noticed in that of nitrate and ammonia.

A review of potable water accessibility and sustainability issues in developing countries - case study of Uganda

Providing sources of sustainable and quality potable water in Uganda is a significant public health issue. This project aimed at identifying and prioritizing possible actions on how sustainable high quality potable water in Uganda's water supply systems could be achieved. In that respect, a review of both the current water supply systems and government programs on drinking water in Uganda was completed. Aspects of quantity, quality, treatment methods, infrastructure, storage and distribution of water for different water systems were evaluated and compared with the existing water supply systems in the U.S., Latin America and the Caribbean, for purposes of generating feasible recommendations and opportunities for improvement. Uganda utilizes surface water, groundwater, and rainwater sources for consumption. Surface water covers 15.4% of the land area and serves both urban and rural populations. Lake Victoria contributes about 85% of the total fresh surface water. Potable water quality is negatively affected by the following factors: disposal of sewage and industrial effluents, agricultural pesticides and fertilizers, and surface run-offs during heavy rains. The total renewable groundwater resources in Uganda are estimated to be 29 million m3/year with about 20,000 boreholes, 3000 shallow-wells and 200,000 springs, serving more than 80% of the rural and slum communities. Mean annual rainfall in Uganda ranges from 500 mm to 2500 mm. Groundwater and rainwater quality is mainly affected by poor sanitation and unhygienic practices. There are significant regional variations in the accessibility of potable water, with the Northeastern region having the least amount of potable water from all sources. Uganda still lags behind in potable water resource development. Priorities should be placed mainly on measures available for improvement of groundwater and rainwater resource utilization, protection of watersheds, health education, improved water treatment methods and distribution in rural areas, and pollution control and monitoring. Implementing these changes can promote potable water accessibility especially to the poor populations living in rural and urban slum areas because they comprise the majority (80%) of Uganda's population.

Open defecation and childhood stunting in India: an ecological analysis of new data from 112 districts

Poor sanitation remains a major public health concern linked to several important health outcomes; emerging evidence indicates a link to childhood stunting. In India over half of the population defecates in the open; the prevalence of stunting remains very high. Recently published data on levels of stunting in 112 districts of India provide an opportunity to explore the relationship between levels of open defecation and stunting within this population. We conducted an ecological regression analysis to assess the association between the prevalence of open defecation and stunting after adjustment for potential confounding factors. Data from the 2011 HUNGaMA survey was used for the outcome of interest, stunting; data from the 2011 Indian Census for the same districts was used for the exposure of interest, open defecation. After adjustment for various potential confounding factors – including socio-economic status, maternal education and calorie availability – a 10 percent increase in open defecation was associated with a 0.7 percentage point increase in both stunting and severe stunting. Differences in open defecation can statistically account for 35 to 55 percent of the average difference in stunting between districts identified as low-performing and high-performing in the HUNGaMA data. In addition, using a Monte Carlo simulation, we explored the effect on statistical power of the common practice of dichotomizing continuous height data into binary stunting indicators. Our simulation showed that dichotomization of height sacrifices statistical power, suggesting that our estimate of the association between open defecation and stunting may be a lower bound. Whilst our analysis is ecological and therefore vulnerable to residual confounding, these findings use the most recently collected large-scale data from India to add to a growing body of suggestive evidence for an effect of poor sanitation on human growth. New intervention studies, currently underway, may shed more light on this important issue.

Cluster-randomised controlled trials of individual and combined water, sanitation, hygiene and nutritional interventions in rural Bangladesh and Kenya: the WASH Benefits study design and rationale

INTRODUCTION

Enteric infections are common during the first years of life in low-income countries and contribute to growth faltering with long-term impairment of health and development. Water quality, sanitation, handwashing and nutritional interventions can independently reduce enteric infections and growth faltering. There is little evidence that directly compares the effects of these individual and combined interventions on diarrhoea and growth when delivered to infants and young children. The objective of the WASH Benefits study is to help fill this knowledge gap.

METHODS AND ANALYSIS

WASH Benefits includes two cluster-randomised trials to assess improvements in water quality, sanitation, handwashing and child nutrition-alone and in combination-to rural households with pregnant women in Kenya and Bangladesh. Geographically matched clusters (groups of household compounds in Bangladesh and villages in Kenya) will be randomised to one of six intervention arms or control. Intervention arms include water quality, sanitation, handwashing, nutrition, combined water+sanitation+handwashing (WSH) and WSH+nutrition. The studies will enrol newborn children (N=5760 in Bangladesh and N=8000 in Kenya) and measure outcomes at 12 and 24 months after intervention delivery. Primary outcomes include child length-for-age Z-scores and caregiver-reported diarrhoea. Secondary outcomes include stunting prevalence, markers of environmental enteropathy and child development scores (verbal, motor and personal/social). We will estimate unadjusted and adjusted intention-to-treat effects using semiparametric estimators and permutation tests.

ETHICS AND DISSEMINATION

Study protocols have been reviewed and approved by human subjects review boards at the University of California, Berkeley, Stanford University, the International Centre for Diarrheal Disease Research, Bangladesh, the Kenya Medical Research Institute, and Innovations for Poverty Action. Independent data safety monitoring boards in each country oversee the trials. This study is funded by a grant from the Bill & Melinda Gates Foundation to the University of California, Berkeley.

REGISTRATION

Trial registration identifiers (http://www.clinicaltrials.gov): NCT01590095 (Bangladesh), NCT01704105 (Kenya).

Interventions to improve water quality and supply, sanitation and hygiene practices, and their effects on the nutritional status of children

BACKGROUND

Water, sanitation and hygiene (WASH) interventions are frequently implemented to reduce infectious diseases, and may be linked to improved nutrition outcomes in children.

OBJECTIVES

To evaluate the effect of interventions to improve water quality and supply (adequate quantity to maintain hygiene practices), provide adequate sanitation and promote handwashing with soap, on the nutritional status of children under the age of 18 years and to identify current research gaps.

SEARCH METHODS

We searched 10 English-language (including MEDLINE and CENTRAL) and three Chinese-language databases for published studies in June 2012. We searched grey literature databases, conference proceedings and websites, reviewed reference lists and contacted experts and authors.

SELECTION CRITERIA

Randomised (including cluster-randomised), quasi-randomised and non-randomised controlled trials, controlled cohort or cross-sectional studies and historically controlled studies, comparing WASH interventions among children aged under 18 years.

DATA COLLECTION AND ANALYSIS

Two review authors independently sought and extracted data on childhood anthropometry, biochemical measures of micronutrient status, and adherence, attrition and costs either from published reports or through contact with study investigators. We calculated mean difference (MD) with 95% confidence intervals (CI). We conducted study-level and individual-level meta-analyses to estimate pooled measures of effect for randomised controlled trials only.

MAIN RESULTS

Fourteen studies (five cluster-randomised controlled trials and nine non-randomised studies with comparison groups) from 10 low- and middle-income countries including 22,241 children at baseline and nutrition outcome data for 9,469 children provided relevant information. Study duration ranged from 6 to 60 months and all studies included children under five years of age at the time of the intervention. Studies included WASH interventions either singly or in combination. Measures of child anthropometry were collected in all 14 studies, and nine studies reported at least one of the following anthropometric indices: weight-for-height, weight-for-age or height-for-age. None of the included studies were of high methodological quality as none of the studies masked the nature of the intervention from participants.Weight-for-age, weight-for-height and height-for-age z-scores were available for five cluster-randomised controlled trials with a duration of between 9 and 12 months. Meta-analysis including 4,627 children identified no evidence of an effect of WASH interventions on weight-for-age z-score (MD 0.05; 95% CI -0.01 to 0.12). Meta-analysis including 4,622 children identified no evidence of an effect of WASH interventions on weight-for-height z-score (MD 0.02; 95% CI -0.07 to 0.11). Meta-analysis including 4,627 children identified a borderline statistically significant effect of WASH interventions on height-for-age z-score (MD 0.08; 95% CI 0.00 to 0.16). These findings were supported by individual participant data analysis including information on 5,375 to 5,386 children from five cluster-randomised controlled trials.No study reported adverse events. Adherence to study interventions was reported in only two studies (both cluster-randomised controlled trials) and ranged from low (< 35%) to high (> 90%). Study attrition was reported in seven studies and ranged from 4% to 16.5%. Intervention cost was reported in one study in which the total cost of the WASH interventions was USD 15/inhabitant. None of the studies reported differential impacts relevant to equity issues such as gender, socioeconomic status and religion.

AUTHORS' CONCLUSIONS

The available evidence from meta-analysis of data from cluster-randomised controlled trials with an intervention period of 9-12 months is suggestive of a small benefit of WASH interventions (specifically solar disinfection of water, provision of soap, and improvement of water quality) on length growth in children under five years of age. The duration of the intervention studies was relatively short and none of the included studies is of high methodological quality. Very few studies provided information on intervention adherence, attrition and costs. There are several ongoing trials in low-income country settings that may provide robust evidence to inform these findings.

Speeding up the solar water disinfection process (SODIS) against Cryptosporidium parvum by using 2.5l static solar reactors fitted with compound parabolic concentrators (CPCs)

Water samples of 0, 5, and 100 nephelometric turbidity units (NTU) spiked with Cryptosporidium parvum oocysts were exposed to natural sunlight in 2.5l static borosilicate solar reactors fitted with two different compound parabolic concentrators (CPCs), CPC1 and CPC1.89, with concentration factors of the solar radiation of 1 and 1.89, respectively. The global oocyst viability was calculated by the evaluation of the inclusion/exclusion of the fluorogenic vital dye propidium iodide and the spontaneous excystation. Thus, the initial global oocyst viability of the C. parvum isolate used was 95.3 ± 1.6%. Using the solar reactors fitted with CPC1, the global viability of oocysts after 12h of exposure was zero in the most turbid water samples (100 NTU) and almost zero in the other water samples (0.3 ± 0.0% for 0 NTU and 0.5 ± 0.2% for 5 NTU). Employing the solar reactors fitted with CPC1.89, after 10h exposure, the global oocyst viability was zero in the non-turbid water samples (0 NTU), and it was almost zero in the 5 NTU water samples after 8h of exposure (0.5 ± 0.5%). In the most turbid water samples (100 NTU), the global viability was 1.9 ± 0.6% after 10 and 12h of exposure. In conclusion, the use of these 2.5l static solar reactors fitted with CPCs significantly improved the efficacy of the SODIS technique as these systems shorten the exposure times to solar radiation, and also minimize the negative effects of turbidity. This technology therefore represents a good alternative method for improving the microbiological quality of household drinking water in developing countries.

Evaluation of the impact of the plastic BioSand filter on health and drinking water quality in rural Tamale, Ghana

A randomized controlled trial of the plastic BioSand filter (BSF) was performed in rural communities in Tamale (Ghana) to assess reductions in diarrheal disease and improvements in household drinking water quality. Few studies of household water filters have been performed in this region, where high drinking water turbidity can be a challenge for other household water treatment technologies. During the study, the longitudinal prevalence ratio for diarrhea comparing households that received the plastic BSF to households that did not receive it was 0.40 (95% confidence interval: 0.05, 0.80), suggesting an overall diarrheal disease reduction of 60%. The plastic BSF achieved a geometric mean reduction of 97% and 67% for E. coli and turbidity, respectively. These results suggest the plastic BSF significantly improved drinking water quality and reduced diarrheal disease during the short trial in rural Tamale, Ghana. The results are similar to other trials of household drinking water treatment technologies.

Solar water disinfection (SODIS): a review from bench-top to roof-top

Solar water disinfection (SODIS) has been known for more than 30 years. The technique consists of placing water into transparent plastic or glass containers (normally 2L PET beverage bottles) which are then exposed to the sun. Exposure times vary from 6 to depending on the intensity of sunlight and sensitivity of the pathogens. Its germicidal effect is based on the combined effect of thermal heating of solar light and UV radiation. It has been repeatedly shown to be effective for eliminating microbial pathogens and reduce diarrhoeal morbidity including cholera. Since 1980 much research has been carried out to investigate the mechanisms of solar radiation induced cell death in water and possible enhancement technologies to make it faster and safer. Since SODIS is simple to use and inexpensive, the method has spread throughout the developing world and is in daily use in more than 50 countries in Asia, Latin America, and Africa. More than 5 million people disinfect their drinking water with the solar disinfection (SODIS) technique. This review attempts to revise all relevant knowledge about solar disinfection from microbiological issues, laboratory research, solar testing, up to and including real application studies, limitations, factors influencing adoption of the technique and health impact.

Comparison of different solar reactors for household disinfection of drinking water in developing countries: evaluation of their efficacy in relation to the waterborne enteropathogen Cryptosporidium parvum

Solar water disinfection (SODIS) is a type of treatment that can significantly improve the microbiological quality of drinking water at household level and therefore prevent waterborne diseases in developing countries. Cryptosporidium parvum is an obligate protozoan parasite responsible for the diarrhoeal disease cryptosporidiosis in humans and animals. Recently, this parasite has been selected by the WHO as a reference pathogen for protozoan parasites in the evaluation of household water treatment options. In this study, the field efficacy of different static solar reactors [1.5 l transparent plastic polyethylene terephthalate (PET) bottles as well as 2.5 l borosilicate glass and 25 l methacrylate reactors fitted with compound parabolic concentrators (CPC)] for solar disinfection of turbid waters experimentally contaminated with C. parvum oocysts was compared. Potential oocyst viability was determined by inclusion/exclusion of the fluorogenic vital dye propidium iodide. The results demonstrate that static solar reactors fitted with CPCs are an excellent alternative to the conventional SODIS method with PET bottles. These reactors improved the efficacy of the SODIS method by enabling larger volumes of water to be treated and, in some cases, the C. parvum oocysts were rendered totally unviable, minimising the negative effects of turbidity.

Solar water disinfection (SODIS) of Escherichia coli, Enterococcus spp., and MS2 coliphage: effects of additives and alternative container materials

The use of alternative container materials and added oxidants accelerated the inactivation of MS2 coliphage and Escherichia coli and Enterococcus spp. bacteria during solar water disinfection (SODIS) trials. Specifically, bottles made from polypropylene copolymer (PPCO), a partially UVB-transparent plastic, resulted in three-log inactivation of these organisms in approximately half the time required for disinfection in bottles made from PET, polycarbonate, or Tritan(®), which absorb most UVB light. Furthermore, the addition of 125 mg/L sodium percarbonate in combination with either citric acid or copper plus ascorbate tended to accelerate inactivation by factors of 1.4-19. Finally, it was observed that the inactivation of E. coli and enterococci derived from local wastewater was far slower than the inactivation of laboratory-cultured E. coli and Enterococcus spp., while the inactivation of MS2 was slowest of all. These results highlight the importance of UVB in SODIS under certain conditions, and also the greater sunlight resistance of some viruses and of bacteria of fecal origin, as compared to the laboratory-cultured bacteria commonly used to model their inactivation. Furthermore, this study illustrates promising new avenues for accelerating the inactivation of bacteria and viruses by solar disinfection.