Solar disinfection of water for diarrhoeal prevention in southern India

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.

Acceptability measures of water, sanitation and hygiene interventions in low- and middle-income countries, a systematic review

BACKGROUND

Inadequate access to water, sanitation, and hygiene (WASH) is an environmental risk factor for poor health outcomes globally, particularly for children in low- and middle-income countries (LMIC). Despite technological advancements, many interventions aimed at improving WASH access return less than optimal results on long term impact, efficacy and sustainability. Research focus in the 'WASH sector' has recently expanded from investigating 'which interventions work' to 'how they are best implemented'. The 'acceptability' of an intervention is a key component of implementation that can influence initial uptake and sustained use. Acceptability assessments are increasingly common for health interventions in clinical settings. A broad scale assessment of how acceptability has been measured in the WASH sector, however, has not yet been conducted.

METHODS/PRINCIPAL FINDINGS

We conducted a systematic literature review of intervention studies published between 1990 and 2021 that evaluated the acceptability of WASH interventions in LMIC settings. Using an implementation science approach, focused outcomes included how acceptability was measured and defined, and the timing of acceptability assessment. We conducted quality assessment for all included studies using the Cochrane Risk of Bias tool for randomised studies, and the Newcastle-Ottawa Scale for non-randomised studies. Of the 1238 records; 36 studies were included for the analysis, 22 of which were non-randomized interventions and 16 randomized or cluster-randomized trials. We found that among the 36 studies, four explicitly defined their acceptability measure, and six used a behavioural framework to inform their acceptability study design. There were few acceptability evaluations in schools and healthcare facilities. While all studies reported measuring WASH acceptability, the measures were often not comparable or described.

CONCLUSIONS

As focus in WASH research shifts towards implementation, a consistent approach to including, defining, and measuring acceptability is needed.

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.

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.

High-performance low-cost solar collectors for water treatment fabricated with recycled materials, open-source hardware and 3d-printing technologies

Solar technologies constitute an excellent alternative for water treatment in low-income countries where the poverty of a large part of the population hinders their access to safe water. From a technical point of view, the use of compound parabolic collectors (CPC) has been consolidated in the last decades. However, the relatively high cost of tooling conventional manufacturing processes for these collectors makes them difficult to afford in the most impoverished regions. This work presents the development of low-cost CPC and parabolic through solar collectors (PTC) by 3D printing of the structure and the use of recycled reflective materials. Besides, open-source hardware has been used to control system operation, including a supplementary UV LED system to compensate for the operation under low solar irradiance. Regarding the tested reflective materials, an optimum is obtained using an aluminium adhesive sheet that leads to an efficiency of 80% compared to a commercial CPC made of high-quality anodised aluminium, being the cost 20 times lower. On the other hand, incorporating a low-cost solar tracking system in a printed PTC reactor could lead to efficiencies up to 300% compared to the commercial CPC, while the cost was 4.5 times lower. Finally, the LED compensation system was successfully validated, allowing the operation with a constant treatment capacity during operation in cloudy conditions. In conclusion, the developed collectors are high-performance solar water treatment systems with a significantly lower investment cost, making them affordable worldwide.

Solar Water Disinfection to Produce Safe Drinking Water: A Review of Parameters, Enhancements, and Modelling Approaches to Make SODIS Faster and Safer

Solar water disinfection (SODIS) is one the cheapest and most suitable treatments to produce safe drinking water at the household level in resource-poor settings. This review introduces the main parameters that influence the SODIS process and how new enhancements and modelling approaches can overcome some of the current drawbacks that limit its widespread adoption. Increasing the container volume can decrease the recontamination risk caused by handling several 2 L bottles. Using container materials other than polyethylene terephthalate (PET) significantly increases the efficiency of inactivation of viruses and protozoa. In addition, an overestimation of the solar exposure time is usually recommended since the process success is often influenced by many factors beyond the control of the SODIS-user. The development of accurate kinetic models is crucial for ensuring the production of safe drinking water. This work attempts to review the relevant knowledge about the impact of the SODIS variables and the techniques used to develop kinetic models described in the literature. In addition to the type and concentration of pathogens in the untreated water, an ideal kinetic model should consider all critical factors affecting the efficiency of the process, such as intensity, spectral distribution of the solar radiation, container-wall transmission spectra, ageing of the SODIS reactor material, and chemical composition of the water, since the substances in the water can play a critical role as radiation attenuators and/or sensitisers triggering the inactivation process.

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.

Barriers and Enabling Factors Associated with the Implementation of Household Solar Water Disinfection: A Qualitative Study in Northwest Ethiopia

Household water treatment including solar disinfection (SODIS) is recognized worldwide as an important intervention for prevention and control of diarrheal and other waterborne diseases. However, in Ethiopia's countryside, SODIS is not being practiced. Therefore, the objective of this qualitative study conducted in villages of Dabat district in northwest Ethiopia was to explore barriers to and enabling factors for consistent and wider implementation of SODIS. This phenomenological study design included four focus group discussions with 25 parents of children younger than 5 years and interviews with four key informants to elicit their experiences and opinions. ATLAS.ti 8.0 software (GmbH, Berlin, Germany) was used for data organization, and the content was analyzed thematically. Enabling factors were categorized into four themes, such as supportive values for SODIS (positive attitude, advantage of SODIS, and cultural acceptance of SODIS), consistent use of SODIS (community's interest, health education, availability of bright sunlight, and simplicity of the method), participation of family and community in daily implementation of the SODIS process (controlling theft of bottles and recognizing the importance of SODIS technology), and willingness to pay for new polyethylene terephthalate (PET) bottles. On the other hand, barriers were grouped into three themes such as sociocultural (poor knowledge, hesitation to leave SODIS bottles unguarded outdoor, less attention, and unplanned social events), environmental (cloud, shadow over SODIS bottles, turbidity and leeches in source water, and geographical settings), and behavioral (mishandling of SODIS bottles and drinking water). The analysis of the data revealed that all the participants had positive attitude toward the implementation of SODIS, and it was culturally accepted. They identified the barriers to and enabling factors for the implementation of SODIS. Promoting enabling factors and mitigating barriers are substantially important for consistent implementation of SODIS as a long-term interventional measure widely in rural Ethiopia for the achievement of the goal of safe drinking water for all.

The effectiveness of solar disinfection water treatment method for reducing childhood diarrhea: a systematic review and meta-analysis protocol

BACKGROUND

Several studies employing the effectiveness of solar disinfection water treatment method for reducing diarrhea have reported heterogeneous outcomes, necessitating a systematic review to provide an exhaustive summary of current evidence. Thus, the objective of this review is to pool out the available evidence on the effectiveness of solar disinfection water treatment method for reducing childhood diarrhea.

METHODS

Searches will be conducted in PubMed/Medline, Scopus, Google Scholar, Cochrane Library databases, and reference of other studies published through in December 2019. Studies that compare the diarrhea incidence among 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 primary outcome of the study is the change in observed diarrhea incidence risk from baseline to post-intervention. Randomized controlled trial study designs will be included. Selected studies will be critically appraised by two independent reviewers. Extracted data will include details about the interventions, populations, study methods, and outcomes of significance to the review question and objectives. Effect sizes will be expressed as risk ratio, and their 95% confidence intervals will be calculated for analysis.

DISCUSSION

This review and meta-analysis will systematically explore and integrate the evidence available on the effectiveness of solar disinfection water treatment method for reducing diarrhea. In this review, information about the potential impact of solar disinfection water treatment to inactivate pathogenic microbes for reducing diarrhea will be gathered and summarized. The findings from this study will provide directions for future research and public health professionals with an understanding of the importance of solar disinfection water treatment and point to directions for applicability of the interventions in the community.

Risk factors for diarrhoea and malnutrition among children under the age of 5 years in the Tigray Region of Northern Ethiopia

BACKGROUND

Diarrhoea and malnutrition are the leading cause of morbidity and mortality among children in areas with poor access to clean water, improved sanitation, and with low socioeconomic status. This study was designed to determine the prevalence of diarrhoea, malnutrition and risk factors among children aged 6-59 months in the Tigray Region of Northern Ethiopia.

METHODS

A community based cross-sectional study design was conducted from June to August 2017 to assess the magnitude and factors associated with diarrhoea and malnutrition among children. A standardized questionnaire was used to collect data on diarrhoea, environmental, demographic and behavioural factors from 610 mother-child pairs. Anthropometric measurements were collected from the children. SPSS ver.21 statistical software was used for analysis. Factors associated with diarrhoea and nutritional status were identified using bivariate and multivariate logistic regression. A p-value ≤ 0.05 was considered statistically significant.

RESULTS

Of the 610 children monitored in this study, the incidence of diarrhoea among 6-59 month-old children in the two weeks preceding the day of the interview day was 27.2% (95% CI: 23.6-31%). Specifically, 35.9%, 9.7%, and 1.8% had 1-2, 3-4 and 5-6 times of diarrhoea episodes in a one year of time, respectively. The prevalence of stunting, underweight, wasting, and acute under-nutrition were 36.1% (95% CI: 31-38.6%), 37% (95% CI: 32-39.6%), 7.9% (95% CI: 5.5-9.7%), and 5.4% (95% CI: 3.8-7.4%), respectively. In a multivariate logistic regression analysis, type of drinking water source [AOR = 3.69; 95% CI: 2.03-6.71], mothers not hand washing at critical times [AOR = 15.42; 95% CI: 2.02-117.78], improper solid waste disposal [AOR = 12.81; 95% CI: 2.50-65.62], and child age (36-47 months) [AOR = 2.57; 95% CI: 1.45-4.55] were found to be predictors of diarrhoea. Being within the age range of 12-23 months was a predictor for wasting [AOR = 4.38; 95% CI: 1.61-11.90] and being underweight [AOR = 4.4; 95% CI: 1.7-11.2]. Similarly, the age range of 36-47 months was associated with wasting [AOR = 2.3; 95% CI: 1.45-3.85] and stunting [AOR = 1.7; 95% CI: 1.03-2.67]. Family size (less than 4) [AOR = 0.56; 95% CI: 0.368-0.959] was inversely associated for wasting.

CONCLUSIONS

Our study revealed that the problem of diarrhoea and malnutrition amongst 6-59 months children in the study area was significant. Access to clean water was the main problem in the study area. Hence, improving access to clean water and providing health education to mothers on personal and environmental hygiene, and proper waste disposal could improve diarrhoea in the study area. Intervention on children's nutrition should also be implemented to minimize the problem of malnutrition.

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.

Access to Household Water Quality Information Leads to Safer Water: A Cluster Randomized Controlled Trial in india

Household-specific feedback on the microbiological safety of drinking water may result in changes to water management practices that reduce exposure risks. We conducted a randomized, controlled trial in India to determine if information on household drinking water quality could change behavior and improve microbiological quality as indicated by Escherichia coli counts. We randomly assigned 589 participating households to one of three arms: (1) a messaging-only arm receiving messaging on safe water management ( n = 237); (2) a standard testing arm receiving the same messaging plus laboratory E. coli testing results specific to that household's drinking water ( n = 173); and (3) a test kit arm receiving messaging plus low-cost E. coli tests that could be used at the household's discretion ( n = 179). Self-reported water treatment increased significantly in both the standard testing arm and the test kit arm between baseline and follow-up one month later. Mean log₁₀ E. coli counts per 100 mL in household stored drinking water increased in the messaging-only arm from 1.42 to 1.87, while decreasing in the standard testing arm (1.38 to 0.89, 65% relative reduction) and the test kit arm (1.08 to 0.65, 76% relative reduction). Findings indicate that household-specific water quality information can improve both behaviors and drinking water quality.

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.

Enteric pathogens and factors associated with acute bloody diarrhoea, Kenya

BACKGROUND

Shigellosis is the major cause of bloody diarrhoea worldwide and is endemic in most developing countries. In Kenya, bloody diarrhoea is reported weekly as part of priority diseases under Integrated Disease Surveillance and Response System (IDSR) in the Ministry of Health.

METHODS

We conducted a case control study with 805 participants (284 cases and 521 controls) between January and December 2012 in Kilifi and Nairobi Counties. Kilifi County is largely a rural population whereas Nairobi County is largely urban. A case was defined as a person of any age who presented to outpatient clinic with acute diarrhoea with visible blood in the stool in six selected health facilities in the two counties within the study period. A control was defined as a healthy person of similar age group and sex with the case and lived in the neighbourhood of the case.

RESULTS

The main presenting clinical features for bloody diarrhoea cases were; abdominal pain (69 %), mucous in stool (61 %), abdominal discomfort (54 %) and anorexia (50 %). Pathogen isolation rate was 40.5 % with bacterial and protozoal pathogens accounting for 28.2 % and 12.3 % respectively. Shigella was the most prevalent bacterial pathogen isolated in 23.6 % of the cases while Entamoeba histolytica was the most prevalent protozoal pathogen isolated in 10.2 % of the cases. On binary logistic regression, three variables were found to be independently and significantly associated with acute bloody diarrhoea at 5 % significance level; storage of drinking water separate from water for other use (OR = 0.41, 95 % CI 0.20-0.87, p = 0.021), washing hands after last defecation (OR = 0.24, 95 % CI 0.08-.076, p = 0.015) and presence of coliforms in main source water (OR = 2.56, CI 1.21-5.4, p = 0.014). Rainfall and temperature had strong positive correlation with bloody diarrhoea.

CONCLUSION

The main etiologic agents for bloody diarrhoea were Shigella and E. histolytica. Good personal hygiene practices such as washing hands after defecation and storing drinking water separate from water for other use were found to be the key protective factors for the disease while presence of coliform in main water source was found to be a risk factor. Implementation of water, sanitation and hygiene (WASH) interventions is therefore key in prevention and control of bloody diarrhoea.

Effectiveness of Membrane Filtration to Improve Drinking Water: A Quasi-Experimental Study from Rural Southern India

Since point-of-use methods of water filtration have shown limited acceptance in Vellore, southern India, this study evaluated the effectiveness of decentralized membrane filtration 1) with safe storage, 2) without safe storage, versus 3) no intervention, consisting of central chlorination as per government guidelines, in improving the microbiological quality of drinking water and preventing childhood diarrhea. Periodic testing of water sources, pre-/postfiltration samples, and household water, and a biweekly follow up of children less than 2 years of age was done for 1 year. The membrane filters achieved a log reduction of 0.86 (0.69–1.06), 1.14 (0.99–1.30), and 0.79 (0.67–0.94) for total coliforms, fecal coliforms, and Escherichia coli, respectively, in field conditions. A 24% (incidence rate ratio, IRR [95% confidence interval, CI] = 0.76 [0.51–1.13]; P = 0.178) reduction in diarrheal incidence in the intervention village with safe storage and a 14% (IRR [95% CI] = 1.14 [0.75–1.77]; P = 0.530) increase in incidence for the intervention village without safe storage versus no intervention village was observed, although not statistically significant. Microbiologically, the membrane filters decreased fecal contamination; however, provision of decentralized membrane-filtered water with or without safe storage was not protective against childhood diarrhea.

Community challenges when using large plastic bottles for Solar Energy Disinfection of Water (SODIS)

BACKGROUND

Communities living in developing countries as well as populations affected by natural or man-made disasters can be left at great risk from water related diseases, especially those spread through the faecal-oral route. Conventional water treatments such as boiling and chlorination can be effective but may prove costly for impoverished communities. Solar water disinfection (SODIS) has been shown to be a cheap and effective way for communities to treat their water. The exposure to sunlight is typically carried out in small volume plastic beverage bottles (up to 2 l). Given the water requirements of consumption and basic personal hygiene, this may not always meet the needs of communities. Recent work has shown 19-L plastic water dispenser containers to be effective SODIS reactors, comparable in efficacy to PET bottles. In this paper we outline the need for studying SODIS in large volumes and discuss 4 main associated challenges.

DISCUSSION

Apart from clean water needed for consumption, access to adequate water is essential for sanitation and hygiene. Contamination of treated water through unwashed hands or vessels contributes heavily to the spread of water borne pathogens in communities. Traditional water treatments such as boiling and chlorination can be effective but may prove financially burdensome for low income communities. SODIS in large vessels could be used as a simple method to meet water requirements in low income and disaster affected populations. However, there have been some concerns associated with the conventional SODIS method; we identify the main ones to be: (1) cold or cloudy weather; (2) the fear of leaching in plastic bottles; (3) water turbidity, and; (4) community acceptance. The application of SODIS in large bottles like WDCs has the potential to be an efficient and cost effective method of disinfecting water, either for consumption until more rigorous water treatments can be put in place, or for sanitation and hygiene to curb the spread of fecal contamination. Further research is needed that can address some of the limitations and challenges associated with the use of large bottles for SODIS.

Fecal contamination of drinking water in Kericho District, Western Kenya: role of source and household water handling and hygiene practices

Inadequate protection of water sources, and poor household hygienic and handling practices have exacerbated fecal water contamination in Kenya. This study evaluated the rate and correlates of thermotolerant coliform (TTC) household water contamination in Kericho District, Western Kenya. Culture and multiplex polymerase chain reaction (PCR) techniques were used to characterize TTCs. The disk diffusion method was used for antibiotic susceptibility profiling of pathogenic Escherichia coli. Out of the 103 households surveyed, 48 (46.6%) had TTC contaminated drinking water (TTC levels of >10 cfu/100 mL). Five of these households were contaminated with pathogenic E. coli, including 40% enteroaggregative E. coli, 40% enterotoxigenic E. coli, and 20% enteropathogenic E. coli. All these pathogenic E. coli strains were multidrug resistant to sulfamethoxazole/trimethoprim, ampicillin, tetracycline and ampicillin/sulbactam. Rural household locality, drinking water hand contact, water storage container cleaning practice, hand washing before water withdrawal, water source total coliforms <10 cfu/100 mL, temperature, and free chlorine levels were associated with TTC contamination of household drinking water. Significant proportions of household drinking water in Kericho District are contaminated with TTCs including with pathogenic multidrug-resistant E. coli. Source and household hygiene and practices contribute significantly to drinking water contamination.

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.

Prevalence and risk factors of diarrhea morbidity among under-five children in India: A systematic review and meta-analysis

BACKGROUND

Acute diarrhea accounts for a huge burden of infectious diseases in under-five children.

OBJECTIVE

This systematic review was carried out to study the prevalence and associated risk factors of diarrhea among Indian children aged <5 years.

METHODS

Papers were identified by a comprehensive electronic search of relevant medical subject heading (MeSH) terms in PubMed. Identified articles were independently reviewed against inclusion/exclusion criteria and rated for quality. 15 articles were abstracted and reviewed to identify the reported prevalence and risk factors for childhood diarrhea. Meta-analysis was done for calculating the pooled prevalence of diarrhea and point estimates of risk factors using random effects model with use of appropriate population weights, and depicted using forest plot.

RESULTS

The overall prevalence of diarrhea between 2002 and 2013 was 21.70% (95% confidence interval [CI]: 11.24-34.46). The significantly associated risk factors were malnutrition (odds ratio [OR]: 1.73, 95% CI: 1.53-1.96) and anemia (OR: 1.71, 95% CI: 1.29-2.28) in child, and low socioeconomic status (OR: 7.14, 95% CI: 2.19-23.32). Age of the child <24 months, not breastfeeding, mothers' low literacy status and untreated drinking water did not show a significant association. Sex of the child, religion, higher education of mothers, and seasonality were found to be inconsistently associated in single studies.

CONCLUSION

It was concluded that there is sufficient evidence on the association of childhood diarrhea with socio-demographic factors, but evidence on other contributory factors including breastfeeding and vaccination is inconclusive. There is need to conduct more analytical studies on lesser known risk factors of diarrhea to establish their risk factors in Indian children.

Perception of drinking water safety and factors influencing acceptance and sustainability of a water quality intervention in rural southern India

BACKGROUND

Acceptance and long-term sustainability of water quality interventions are pivotal to realizing continued health benefits. However, there is limited research attempting to understand the factors that influence compliance to or adoption of such interventions.

METHODS

Eight focus group discussions with parents of young children--including compliant and not compliant households participating in an intervention study, and three key-informant interviews with village headmen were conducted between April and May 2014 to understand perceptions on the effects of unsafe water on health, household drinking water treatment practices, and the factors influencing acceptance and sustainability of an ongoing water quality intervention in a rural population of southern India.

RESULTS

The ability to recognize health benefits from the intervention, ease of access to water distribution centers and the willingness to pay for intervention maintenance were factors facilitating acceptance and sustainability of the water quality intervention. On the other hand, faulty perceptions on water treatment, lack of knowledge about health hazards associated with drinking unsafe water, false sense of protection from locally available water, resistance to change in taste or odor of water and a lack of support from male members of the household were important factors impeding acceptance and long term use of the intervention.

CONCLUSION

This study highlights the need to effectively involve communities at important stages of implementation for long term success of water quality interventions. Timely research on the factors influencing uptake of water quality interventions prior to implementation will ensure greater acceptance and sustainability of such interventions in low income settings.

Environmental predictors of diarrhoeal infection for rural and urban communities in south India in children and adults

Diarrhoeal diseases are major causes of morbidity and mortality in developing countries. This longitudinal study aimed to identify controllable environmental drivers of intestinal infections amidst a highly contaminated drinking water supply in urban slums and villages of Vellore, Tamil Nadu in southern India. Three hundred households with children (<5 years) residing in two semi-urban slums and three villages were visited weekly for 12-18 months to monitor gastrointestinal morbidity. Households were surveyed at baseline to obtain information on environmental and behavioural factors relevant to diarrhoea. There were 258 diarrhoeal episodes during the follow-up period, resulting in an overall incidence rate of 0·12 episodes/person-year. Incidence and longitudinal prevalence rates of diarrhoea were twofold higher in the slums compared to rural communities (P < 0·0002). Regardless of study site, diarrhoeal incidence was highest in infants (<1 year) at 1·07 episodes/person-year, and decreased gradually with increasing age. Increasing diarrhoeal rates were associated with presence of children (<5 years), domesticated animals and low socioeconomic status. In rural communities, open-field defecation was associated with diarrhoea in young children. This study demonstrates the contribution of site-specific environmental and behavioural factors in influencing endemic rates of urban and rural diarrhoea in a region with highly contaminated drinking water.

Explaining low rates of sustained use of siphon water filter: evidence from follow-up of a randomised controlled trial in Bangladesh

OBJECTIVE

To assess sustained siphon filter usage among a low-income population in Bangladesh and study relevant motivators and barriers.

METHODS

After a randomised control trial in Bangladesh during 2009, 191 households received a siphon water filter along with educational messages. Researchers revisited households after 3 and 6 months to assess filter usage and determine relevant motivators and barriers. Regular users were defined as those who reported using the filter most of the time and were observed to be using the filter at follow-up visits. Integrated behavioural model for water, sanitation and hygiene (IBM-WASH) was used to explain factors associated with regular filter use.

RESULTS

Regular filter usage was 28% at the 3-month follow-up and 21% at the 6-month follow-up. Regular filter users had better quality water at the 6-month, but not at the 3-month visit. Positive predictors of regular filter usage explained through IBM-WASH at both times were willingness to pay >US$1 for filters, and positive attitude towards filter use (technology dimension at individual level); reporting boiling drinking water at baseline (psychosocial dimension at habitual level); and Bengali ethnicity (contextual dimension at individual level). Frequently reported barriers to regular filter use were as follows: considering filter use an additional task, filter breakage and time required for water filtering (technology dimension at individual level).

CONCLUSION

The technological, psychosocial and contextual dimensions of IBM-WASH contributed to understanding the factors related to sustained use of siphon filter. Given the low regular usage rate and the hardware-related problems reported, the contribution of siphon filters to improving water quality in low-income urban communities in Bangladesh is likely to be minimal.

Comparison of the burden of diarrhoeal illness among individuals with and without household cisterns in northeast Brazil

Background

Lack of access to safe and secure water is an international issue recognized by the United Nations. To address this problem, the One Million Cisterns Project was initiated in 2001 in Brazil’s semi-arid region to provide a sustainable source of water to households. The objectives of this study were to determine the 30-day period prevalence of diarrhoea in individuals with and without cisterns and determine symptomology, duration of illness and type of health care sought among those with diarrhoea. A subgroup analysis was also conducted among children less than five years old.

Methods

A face-to-face survey was conducted between August 20th and September 20th, 2007 in the Agreste Central Region of Pernambuco State, Brazil. Households with and without a cistern that had at least one child under the age of five years were selected using systematic convenient sampling. Differences in health outcomes between groups were assessed using Pearson’s Chi-squared and two-way t-tests. Demographic variables were tested for univariable associations with diarrhoea using logistic regression with random effects. P-values of 0.05 or less were considered statistically significant.

Results

A total of 3679 people from 774 households were included in the analysis (1863 people from 377 households with cisterns and 1816 people from 397 households without cisterns). People from households with a cistern had a significantly lower 30-day period prevalence of diarrhoea (prevalence = 11.0%; 95% CI 9.5-12.4) than people from households without a cistern (prevalence = 18.2%; 95% CI 16.4-20.0). This significant difference was also found in a subgroup analysis of children under five years old; those children with a cistern had a 30-day period prevalence of 15.6% (95% CI 12.3-18.9) versus 26.7% (95% CI 22.8-30.6) in children without a cistern. There were no significant differences between those people with and without cisterns in terms of the types of symptoms, duration of illness and health care sought for diarrhoea.

Conclusions

Our results indicate that the use of cisterns for drinking water is associated with a decreased occurrence of diarrhoea in this study population. Further research accounting for additional risk factors and preventative factors should be conducted.

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.

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.

Contribution of UVB radiation to bacterial inactivation by natural sunlight

The contribution of different components of sunlight to the lethal action exerted by this radiation on bacteria was studied using Pseudomonas aeruginosa ATCC27853 as a model organism. When solar UVB was excluded from the incident radiation by filtering it through a naphthalene solution (cut off 327 nm), significant modifications were observed in the cell-death kinetics. These modifications were comparable to those expected for a reduction of 27-32% in the dose rate, according to the model used in the analysis of the survival curves, and were also observed when the effects of sunlight filtered through polyethylene terephthalate (cut off 331 nm) or polystyrene (cut off 298 nm) were compared. Viability of P. aeruginosa remained almost unchanged when the incident radiation was filtered through a sodium nitrite solution (cut off 406 nm) in order to exclude the UVA and UVB components of sunlight. Nevertheless, a delay in colony formation was detected in bacteria treated in this way, suggesting that a non-lethal effect was exerted by visible light. The results are not consistent with a generally accepted notion which attributes the lethal action of sunlight to the radiation with wavelengths above 320 nm. The characterization of UVB contribution to the lethal effect of sunlight on bacteria is relevant for understanding of the mechanism of cell death, and for improvement of dosimetry techniques and irradiation procedures.

Toward a systems approach to enteric pathogen transmission: from individual independence to community interdependence

Diarrheal disease is still a major cause of mortality and morbidity worldwide; thus a large body of research has been produced describing its risks. We review more than four decades of literature on diarrheal disease epidemiology. These studies detail a progression in the conceptual understanding of transmission of enteric pathogens and demonstrate that diarrheal disease is caused by many interdependent pathways. However, arguments by diarrheal disease researchers in favor of attending to interaction and interdependencies have only recently yielded more formal systems-level approaches. Therefore, interdependence has not yet been highlighted in significant new research initiatives or policy decisions. We argue for a systems-level framework that will contextualize transmission and inform prevention and control efforts so that they can integrate transmission pathways. These systems approaches should be employed to account for community effects (i.e., interactions among individuals and/or households).

Evaluation of the solar water disinfection process (SODIS) against Cryptosporidium parvum using a 25-L static solar reactor fitted with a compound parabolic collector (CPC)

Water samples of 0, 5, and 30 nephelometric turbidity units (NTU) spiked with Cryptosporidium parvum oocysts were exposed to natural sunlight using a 25-L static solar reactor fitted with a compound parabolic collector (CPC). The global oocyst viability was calculated by the evaluation of the inclusion/exclusion of the fluorogenic vital dye propidium iodide and the spontaneous excystation. After an exposure time of 8 hours, the global oocyst viabilities were 21.8 ± 3.1%, 31.3 ± 12.9%, and 45.0 ± 10.0% for turbidity levels of 0, 5, and 30 NTU, respectively, and these values were significantly lower (P < 0.05) that the initial global viability of the isolate (92.1 ± 0.9%). The 25-L static solar reactor that was evaluated can be an alternative system to the conventional solar water disinfection process for improving the microbiological quality of drinking water on a household level, and moreover, it enables treatment of larger volumes of water (> 10 times).

Risk management in a developing country context: improving decisions about point-of-use water treatment among the rural poor in Africa

More than 1 billion people, the vast majority of which live in the developing world, lack basic access to clean water for domestic use. For this reason, finding and promoting effective and sustainable solutions for the provision of reliable clean water in developing nations has become a focus of several public health and international development efforts. Even though several means of providing centrally located sources of clean water in developing communities exist, the severity and widespread nature of the water problem has led most development agencies and sanitation experts to strongly advocate the use of point-of-use treatment systems alongside whatever source of water people regularly use. In doing so, however, development practitioners have been careful to point out that any interventions or infrastructure regarding water safety and human health must also adhere to one of the central principles of international development: to facilitate more democratic and participatory models of decision making and governance. To this end, the research reported here focused on the development of a deliberative risk management framework for involving affected stakeholders in decisions about POU water treatment systems. This research, which was grounded in previous studies of structured decision making, took place in two rural villages in the East African nation of Tanzania.

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

We report the results of a randomized controlled intervention study (September 2007 to March 2009) investigating the effect of solar disinfection (SODIS) of drinking water on the incidence of dysentery, nondysentery diarrhea, and anthropometric measurements of height and weight among children of age 6 months to 5 years living in peri-urban and rural communities in Nakuru, Kenya. We compared 555 children in 404 households using SODIS with 534 children in 361 households with no intervention. Dysentery was recorded using a pictorial diary. Incidence rate ratios (IRR) for both number of days and episodes of dysentery and nondysentery diarrhea were significantly (P < 0.001) reduced by use of solar disinfection: dysentery days IRR = 0.56 (95% CI 0.40 to 0.79); dysentery episodes IRR = 0.55 (95% CI 0.42 to 0.73); nondysentery days IRR = 0.70 (95% CI 0.59 to 0.84); nondysentery episodes IRR = 0.73 (95% CI 0.63 to 0.84). Anthropometry measurements of weight and height showed median height-for-age was significantly increased in those on SODIS, corresponding to an average of 0.8 cm over a 1-year period over the group as a whole (95% CI 0.7 to 1.6 cm, P = 0.031). Median weight-for-age was higher in those on SODIS, corresponding to a 0.23 kg difference in weight over the same period; however, the confidence interval spanned zero and the effect fell short of statistical significance (95% CI -0.02 to 0.47 kg, P = 0.068). SODIS and control households did not differ in the microbial quality of their untreated household water over the follow-up period (P = 0.119), but E. coli concentrations in SODIS bottles were significantly lower than those in storage containers over all follow-up visits (P < 0.001). This is the first trial to show evidence of the effect of SODIS on childhood anthropometry, compared with children in the control group and should alleviate concerns expressed by some commentators that the lower rates of dysentery associated with SODIS are the product of biased reporting rather than reflective of genuinely decreased incidence.

An assessment of continued use and health impact of the concrete biosand filter in Bonao, Dominican Republic

The biosand filter (BSF) is a promising point of use (POU) technology for water treatment; however there has been little follow-up of initial implementation to assess sustainability. The purpose of this study was to examine continued use, performance, and sustainability of previously implemented concrete BSFs in Bonao, Dominican Republic. Of 328 households visited and interviewed, 90% of BSFs were still in use after approximately 1 year since installation. Water-quality improvement, measured by fecal indicator bacteria reduction, was found to be 84-88%, which is lower than reductions in controlled laboratory studies but similar to other field assessments. In a short prospective cohort study comparing BSF to non-BSF households, odds of reported diarrheal disease in BSF households were 0.39 times the odds of reported diarrheal disease in non-BSF households. These results document high levels of sustained and effective concrete BSF use and associated improvements in water quality and health.

High compliance randomized controlled field trial of solar disinfection of drinking water and its impact on childhood diarrhea in rural Cambodia

Recent solar disinfection (SODIS) studies in Bolivia and South Africa have reported compliance rates below 35% resulting in no overall statistically significant benefit associated with disease rates. In this study, we report the results of a 1 year randomized controlled trial investigating the effect of SODIS of drinking water on the incidence of dysentery and nondysentery diarrhea among children of age 6 months to 5 years living in rural communities in Cambodia. We compared 426 children in 375 households using SODIS with 502 children in 407 households with no intervention. Study compliance was greater than 90% with only 5% of children having less than 10 months of follow-up and 2.3% having less than 6 months. Adjusted for water source type, children in the SODIS group had a reduced incidence of dysentery, with an incidence rate ratio (IRR) of 0.50 (95% CI 0.27-0.93, p = 0.029). SODIS also had a protective effect against nondysentery diarrhea, with an IRR of 0.37 (95% CI 0.29-0.48, p < 0.001). This study suggests strongly that SODIS is an effective and culturally acceptable point-of-use water treatment method in the culture of rural Cambodia and may be of benefit among similar communities in neighboring South East Asian countries.

Factors associated with compliance among users of solar water disinfection in rural Bolivia

BACKGROUND

Diarrhoea is the second leading cause of childhood mortality, with an estimated 1.3 million deaths per year. Promotion of Solar Water Disinfection (SODIS) has been suggested as a strategy for reducing the global burden of diarrhoea by improving the microbiological quality of drinking water. Despite increasing support for the large-scale dissemination of SODIS, there are few reports describing the effectiveness of its implementation. It is, therefore, important to identify and understand the mechanisms that lead to adoption and regular use of SODIS.

METHODS

We investigated the behaviours associated with SODIS adoption among households assigned to receive SODIS promotion during a cluster-randomized trial in rural Bolivia. Distinct groups of SODIS-users were identified on the basis of six compliance indicators using principal components and cluster analysis. The probability of adopting SODIS as a function of campaign exposure and household characteristics was evaluated using ordinal logistic regression models.

RESULTS

Standardised, community-level SODIS-implementation in a rural Bolivian setting was associated with a median SODIS use of 32% (IQR: 17-50). Households that were more likely to use SODIS were those that participated more frequently in SODIS promotional events (OR=1.07, 95%CI: 1.01-1.13), included women (OR=1.18, 95%CI: 1.07-1.30), owned latrines (OR=3.38, 95%CI: 1.07-10.70), and had severely wasted children living in the home (OR=2.17, 95%CI: 1.34-3.49).

CONCLUSIONS

Most of the observed household characteristics showed limited potential to predict compliance with a comprehensive, year-long SODIS-promotion campaign; this finding reflects the complexity of behaviour change in the context of household water treatment. However, our findings also suggest that the motivation to adopt new water treatment habits and to acquire new knowledge about drinking water treatment is associated with prior engagements in sanitary hygiene and with the experience of contemporary family health concerns.Household-level factors like the ownership of a latrine, a large proportion of females and the presence of a malnourished child living in a home are easily assessable indicators that SODIS-programme managers could use to identify early adopters in SODIS promotion campaigns.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT00731497.

Solar disinfection of drinking water in the prevention of dysentery in South African children aged under 5 years: the role of participant motivation

Solar disinfection (SODIS) effectively improves the microbial quality of drinking water for preventing diarrhea; however, the effect of participant motivation has not been studied. This 1-year randomized controlled trial investigated the effect of SODIS of drinking water and motivation on the incidence of dysentery and nondysentery diarrhea among children of age 6 months to 5 years living in periurban communities in South Africa.We compared 383 children in 297 households using SODIS with 335 children in 267 households with no intervention. At baseline 62.4% of the study households had stored water which met World Health Organization guidelines for zero thermotolerant coliforms per 100 mL. Dysentery was recorded using a pictorial diary. Incidence of dysentery was significantly associated with higher motivation, defined as 75% or better completion of diarrhea data. Incidence rates were lower in those drinking solar disinfected water (incidence rate ratio 0.64, 95% CI 0.39 - 1.0, P = 0.071) but not statistically significant. Compared with the control, participants with higher motivation achieved a significant reduction in dysentery (incidence rate ratio 0.36, 95% CI 0.16 - 0.81, P = 0.014). However, there was no significant reduction in risk at lower levels of motivation. Solar disinfection was not significantly associated with nondysentery diarrhea risk overall (P = 0.419). A statistically significant reduction in dysentery was achieved only in households with higher motivation, showing that motivation is a significant determinant for measurable health gains. Failure of three-quarters of participants to achieve a significant reduction in dysentery suggests that research into effective implementation is required.

Case-control study to determine risk factors for diarrhea among children during a large outbreak in a country with a high prevalence of HIV infection

OBJECTIVES

Between January and March of 2006, over 35 000 diarrhea cases and 532 deaths were reported among children aged <5 years in Botswana. We conducted an investigation to characterize the outbreak, identify risk factors for diarrhea, and recommend control strategies.

METHODS

We enrolled children <5 years of age presenting to the emergency department between March 2 and March 20, 2006. Cases had ≥3 loose stools per day and no antecedent diarrhea among household members. Controls had had no diarrhea since January 1, 2006. We conducted a multivariate logistic regression analysis controlling for socioeconomic status, age, and maternal HIV status.

RESULTS

Forty-nine cases with median age of 12 months (range 0-45 months) and 61 controls with median age of 24 months (range 0-59 months) were enrolled; 33 (30%) were born to HIV-positive mothers. Case-parents were more likely to report storing household drinking water (adjusted odds ratios (AOR) 3.9, 95% confidence interval (CI) 1.2-15.7). Lack of hand washing after using the toilet or latrine (AOR 4.2, 95% CI 1.1-20.4) was more likely to be reported by case-parents. Case-children were less likely to be currently breastfeeding (AOR 30.3, 95% CI 2.0-1000.0). Five (10%) case-patients and no control-patients died. Multiple causal pathogens were identified.

CONCLUSIONS

During this diarrhea outbreak in a country with a national program to prevent mother-to-child transmission of HIV, ill children were less likely to be breastfed and more likely to have been exposed to environmental factors associated with fecal contamination. These findings underscore the importance of adequate access to safe water, sanitation, hygiene, and nutrition education among populations using breast milk substitutes.

Solar disinfection improves drinking water quality to prevent diarrhea in under-five children in sikkim, India

BACKGROUND

Solar radiations improve the microbiological quality of water and offer a method for disinfection of drinking water that requires few resources and no expertise and may reduce the prevalence of diarrhea among under-five children.

AIMS AND OBJECTIVES

To find out the reduction in the prevalence of diarrhea in the under-five children after consumption of potable water treated with solar disinfection method.

MATERIALS AND METHODS

This was a population-based interventional prospective study in the urban slum area of Mazegoan, Jorethang, south Sikkim, during the period 1(st) May 2007 to 30(th) November 2007 on 136 children in the under-five age group in 102 households selected by random sampling. Main outcome measure was the assessment of the reduction of the prevalence of diarrhea among under-five children after consumption of potable water treated with solar disinfection method practiced by the caregivers in the intervention group keeping water in polyethylene terephthalate (PET) bottles as directed by the investigators. The data were collected by the interview method using a pre-tested questionnaire prepared on the basis of socio-demographics and prevalence of diarrhea. The data were subjected to percentages and chi-square tests, which were used to find the significance.

RESULTS

After four weeks of intervention among the study group, the diarrhea prevalence was 7.69% among solar disinfection (SODIS) users, while 31.82% prevalence was observed among non-users in that period; the reduction in prevalence of diarrhea was 75.83%. After eight weeks of intervention, the prevalence of diarrhea was 7.58% among SODIS users and 31.43% among non-users; the reduction in diarrhea was 75.88% in the study group. The findings were found to be statistically significant.

CONCLUSIONS

In our study, we observed that the prevalence of diarrhea decreased significantly after solar disinfection of water was practiced by the caregivers keeping potable water in PET bottles in the intervention group.

How valuable are environmental health interventions? Evaluation of water and sanitation programmes in India

OBJECTIVE

To evaluate and quantify the economic benefits attributable to improvements in water supply and sanitation in rural India.

METHODS

We combined propensity-score "pre-matching" and rich pre-post panel data on 9500 households in 242 villages located in four geographically different districts to estimate the economic benefits of a large-scale community demand-driven water supply programme in Maharashtra, India. We calculated coping costs and cost of illness by adding across several elements of coping and illness and then estimated causal impacts using a difference-in-difference strategy on the pre-matched sample. The pre-post design allowed us to use a difference-in-difference estimator to measure "treatment effect" by comparing treatment and control villages during both periods. We compared average household costs with respect to out-of-pocket medical expenses, patients' lost income, caregiving costs, time spent on collecting water, time spent on sanitation, and water treatment costs due to filtration, boiling, chemical use and storage.

FINDINGS

Three years after programme initiation, the number of households using piped water and private pit latrines had increased by 10% on average, but no changes in hygiene-related behaviour had occurred. The behavioural changes observed suggest that the average household in a programme community could save as much as 7 United States dollars per month (or 5% of monthly household cash expenditures) in coping costs, but would not reduce illness costs. Poorer, socially marginalized households benefited more, in alignment with programme objectives.

CONCLUSION

Given the renewed interest in water, sanitation and hygiene outcomes, evaluating the economic benefits of environmental interventions by means of causal research is important for understanding the true value of such interventions.

Microbiological effectiveness of disinfecting water by boiling in rural Guatemala

Boiling is the most common means of treating water in the home and the benchmark against which alternative point-of-use water treatment options must be compared. In a 5-week study in rural Guatemala among 45 households who claimed they always or almost always boiled their drinking water, boiling was associated with a 86.2% reduction in geometric mean thermotolerant coliforms (TTC) (N = 206, P < 0.0001). Despite consistent levels of fecal contamination in source water, 71.2% of stored water samples from self-reported boilers met the World Health Organization guidelines for safe drinking water (0 TTC/100 mL), and 10.7% fell within the commonly accepted low-risk category of (1-10 TTC/100 mL). As actually practiced in the study community, boiling significantly improved the microbiological quality of drinking water, though boiled and stored drinking water is not always free of fecal contaminations.

Estimating the scope of household water treatment in low- and medium-income countries

For populations without reliable access to safe drinking water, household water treatment (HWT) provides a means of improving water quality and preventing disease. We extracted data on reported HWT practices from 67 national surveys and reports on the scope of HWT. An estimated 33.0% of the households (1.1 billion people) in these countries report treating their drinking water at home. The practice is widespread in the Western Pacific (66.8%) and Southeast Asia (45.4%) regions, and it is less common in the Eastern Mediterranean (13.6%) and Africa (18.2%). Boiling is the most dominant method with 21.0% of the study households (598 million people) using the method. Despite being at higher risk of waterborne disease because of lower coverage of improved water sources, African and rural households are less likely to practice HWT or use microbiologically adequate methods. Validation of the household surveys and further analysis of these data could help optimize HWT practices.

Solar water disinfection in household settings: hype or hope?

Zulfiqar Bhutta discusses a new trial of solar water disinfection in rural Bolivia, and questions whether such technologies offer just hype or new hope for communities struggling with unclean water and poor sanitation.