A low-cost intervention for cleaner drinking water in Karachi, Pakistan

Adoption of Point-of-Use Chlorination for Household Drinking Water Treatment: A Systematic Review

BACKGROUND

Centralized chlorination of urban piped water supplies has historically contributed to major reductions in waterborne illness. In locations without effective centralized water treatment, point-of-use (POU) chlorination for households is widely promoted to improve drinking water quality and health. Realizing these health benefits requires correct, consistent, and sustained product use, but real-world evaluations have often observed low levels of use. To our knowledge, no prior reviews exist on adoption of chlorine POU products.

OBJECTIVES

Our objectives were to identify which indicators of adoption are most often used in chlorine POU studies, summarize levels of adoption observed, understand how adoption changes over time, and determine how adoption is affected by frequency of contact between participants and study staff.

METHODS

We conducted a systematic review of household POU chlorination interventions or programs from 1990 through 2021 that reported a quantitative measure of adoption, were conducted in low- and middle-income countries, included data collection at households, and reported the intervention start date.

RESULTS

We identified 36 studies of household drinking water chlorination products that met prespecified eligibility criteria and extracted data from 46 chlorine intervention groups with a variety of chlorine POU products and locations. There was no consensus definition of adoption of household water treatment; the most common indicator was the proportion of household stored water samples with free chlorine residual > 0.1  or   0.2 mg / L . Among studies that reported either free or total chlorine-confirmed adoption of chlorine POU products, use was highly variable (across all chlorine intervention groups at the last time point measured in each study; range: 1.5%-100%; sample size-weighted median = 47 % ; unweighted median = 58 % ). The median follow-up duration among intervention groups was 3 months. On average, adoption declined over time and was positively associated with frequency of contact between respondents and study staff.

DISCUSSION

Although prior research has shown that POU chlorine products improve health when correctly and consistently used, a reliance on individual adoption for effective treatment is unlikely to lead to the widespread public health benefits historically associated with pressurized, centralized treatment of piped water supplies. https://doi.org/10.1289/EHP10839.

Sustainable nano-sodium silicate and silver nitrate impregnated locally made ceramic filters for point-of-use water treatments in sub-Sahara African households

The poor access to water quality for Nigerians has pushed for the designing of new trend silver nitrate impregnated locally made Point-Of-Use (POU) ceramic filters to enhance water purification efficiency for household use. This study utilized silver nitrate-molded ceramic filters prepared with Kaolin from Owode, silt soil, sodium silicate, sawdust, and distilled water in three varying proportions to ascertain pollution removal efficiencies. Heating was carried out by firing the filters at 900 °C and further preheating at 400 °C after dipping in silver nitrate solution. Silver nanoparticle and dissociated particle discharge from filter pot painted with 0.03 mg/g casein-covered nAg or AgNO₃ were estimated as an element of pH (5–9), ionic strength (1–50mM), and cation species (Na+, Ca2+, Mg2+). Silver delivery was constrained by disintegration as Ag+ and resulting cation exchange measures, paying little heed to silver structure applied. Water analysis for both heavy metals (Pb and Cd) and microbial load (E. coli) evaluated, corroborate the maximum removal efficiency. It was observed that kaolin-sawdust with the Silver nitrate filters showed a constant and effective removal of both heavy metals and disinfection of microbial loads. The minimum flow rates observed were 4.97 mL/min for batch filter used for Iju River water sample one (AF1) and 4.98 mL/min for batch filter used for Iju River water sample two (AF2) having porosity 49.05% and 50.00%, whereas the 5 mL/min higher flow rate was used for batch filter from borehole water sample one (BF1) and batch filter used for well water sample two (CF2) with porosity of 50.00%. Significantly, the results obtained show that the filters are suitable for point-of-use application in both the urban and rural areas of developing countries such as Nigeria

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.

Experimental Investigations of a Solar Water Treatment System for Remote Desert Areas of Pakistan

Pakistan is among the countries that have already crossed the water scarcity line, and the situation is worsened due to the recent pandemic. This is because the major budget of the country is shifted to primary healthcare activities from other development projects that included water treatment and transportation infrastructure. Consequently, water-borne diseases have increased drastically in the past few months. Therefore, there is a dire need to address this issue on a priority basis to ameliorate the worsening situation. One possible solution is to shift the focus/load from mega-projects that require a plethora of resources, money, and time to small domestic-scale systems for water treatment. For this purpose, domestic-scale solar stills are designed, fabricated, and tested in one of the harshest climatic condition areas of Pakistan, Rahim Yar Khan. A comprehensive overview of the regional climatology, including wind speed, solar potential, and ambient temperature is presented for the whole year. The analysis shows that the proposed system can adequately resolve the drinking water problems of deprived areas of Pakistan. The average water productivity of 1.5 L/d/m2 is achieved with a total investment of PKR 3000 (<$20). This real site testing data will serve as a guideline for similar system design in other arid areas globally.

Climate Change, Water Quality and Water-Related Challenges: A Review with Focus on Pakistan

Climate variability is heavily impacting human health all around the globe, in particular, on residents of developing countries. Impacts on surface water and groundwater resources and water-related illnesses are increasing, especially under changing climate scenarios such as diversity in rainfall patterns, increasing temperature, flash floods, severe droughts, heatwaves and heavy precipitation. Emerging water-related diseases such as dengue fever and chikungunya are reappearing and impacting on the life of the deprived; as such, the provision of safe water and health care is in great demand in developing countries to combat the spread of infectious diseases. Government, academia and private water bodies are conducting water quality surveys and providing health care facilities, but there is still a need to improve the present strategies concerning water treatment and management, as well as governance. In this review paper, climate change pattern and risks associated with water-related diseases in developing countries, with particular focus on Pakistan, and novel methods for controlling both waterborne and water-related diseases are discussed. This study is important for public health care, particularly in developing countries, for policy makers, and researchers working in the area of climate change, water quality and risk assessment.

Variations in sensitivity to chlorine in Ecuador and US consumers: implications for community water systems

Successful implementation of chlorination for disinfecting community water systems in developing countries faces obstacles, with rejection of chlorinous flavor as a significant factor. Determining consumers' abilities to accurately detect chlorine in treated water is important to identifying acceptable chlorination levels that are also effective for water disinfection. Chlorine detection sensitivity was tested in untrained Ecuadorian consumers with limited prior experience with chlorinated water and US consumers with extensive prior experience with chlorinated water. Water samples with free chlorine concentrations up to 3.0 mg/L were presented for flavor testing. Ecuadorian consumers showed higher sensitivity, being able to detect chlorination at 2.0 and 3.0 mg/L, while US consumers did not reliably detect chlorine presence for any concentration levels. Additionally, Ecuadorian consumers' rejection of water samples depended on chlorination, showing a statistically significant increase in rejections of samples with chlorine concentrations above 1.0 mg/L. On the other hand, although US consumers rejected more samples overall, their tendency to reject did not vary as a function of chlorination levels. This study demonstrated that limited experience with chlorination is a critical factor for accurate chlorine flavor detection in drinking water.

Graphical Assessment Technique (GAT) - An Objective, Comprehensive and Comparative Hand Hygiene Quantification Tool

INTRODUCTION

There has been a profound leap in developing countries in sectors of human development but it falls short of millennium development goals. Diarrhoea, respiratory infections are primary cause of child deaths around the world due to improper hygiene practice. There is lack of systematic objective analysis, follow-up and quantification of hand hygiene guidelines. So, there is an urgent requisite of a tool to assess the same.

AIM

To conduct a pilot test for assessing the efficacy of Graphical Assessment Technique (GAT) in objectively evaluating and comparing intervention based hand hygiene among students of National Association of Blind School (NABS) and a government school.

MATERIALS AND METHODS

GAT was used to assess the baseline and post-intervention improvement of 80 students considered for the study. Data was analyzed using SPSS software version 20.0 and was subjected to quantitative analysis and parametric tests.

RESULTS

Non-significant difference (p≥0.05) was found at baseline and immediate post-intervention on percentage mean scores of blind school students and government school student, while government school children also showed non-significant difference at one week. Significant difference (p≤0.05) was found at baseline, post-intervention one week and post-intervention one month for blind school children along with baseline and post-intervention mean percentage scores for government school children.

CONCLUSION

The primary agenda behind the study was to test a tool which can objectively evaluate, quantify and compare the follow-up of hand hygiene guidelines and aid in better hand hygiene promotion.

What Happens When "Germs Don't Get Killed and They Attack Again and Again": Perceptions of Antimicrobial Resistance in the Context of Diarrheal Disease Treatment Among Laypersons and Health-Care Providers in Karachi, Pakistan

In south Asia, where diarrhea is common and antibiotics are accessible without prescription, antimicrobial resistance is an emerging and serious problem. However, beliefs and behaviors related to antimicrobial resistance are poorly understood. We explored laypersons' and health-care providers' (HCP) awareness and perceptions of antimicrobial resistance in the context of treatment of adult diarrheal disease in Karachi, Pakistan. In-depth, open-ended interviews were conducted with 40 laypersons and 45 HCPs in a lower-middle-class urban neighborhood. Interviews conducted in Urdu were audiotaped, transcribed, translated, and coded using applied thematic analysis. Slightly over half of laypersons and two-thirds of HCPs were aware that antimicrobial medication could lose effectiveness, but misperceptions were common. Laypersons and HCPs often believed that "the body becomes immune" or "bacteria attack more strongly" if medications are taken "improperly." Another prevalent theme was that causes and effects of antimicrobial resistance are limited to the individual taking the antimicrobial medication and to the specific diarrheal episode. Participants often attributed antimicrobial resistance to patient behaviors; HCP behavior was rarely discussed. Less than half of the HCPs were aware of treatment guidelines. To combat antimicrobial resistance in urban Pakistan, a health systems strategy and community-supported outreach campaigns on appropriate antimicrobial use are needed.

Determinants of Caregivers' Use and Adoption of Household Water Chlorination: A Qualitative Study with Peri-Urban Communities in the Peruvian Amazon

The gap between the efficacy and the effectiveness of household water treatment in reducing diarrhea-related morbidity indicates the need for a better understanding of the determinants of long-term behavior change. To explore the barriers to drinking water chlorination in the Peruvian Amazon, where diarrhea is endemic among under-5 children, we conducted qualitative research with 23 caregivers from peri-urban communities of Iquitos, Peru. Our inquiry drew on the Transtheoretical Model of behavior change and the Integrated Behavioral Model for Water, Sanitation, and Hygiene to identify the most relevant contextual, psychosocial, and technological determinants of initial action and long-term adoption of chlorination. Our findings suggest that the decision to try out this practice resulted from the combined effect of knowledge of chlorination benefits and product availability and affordability. Progress from action to adoption was influenced by caretakers' understanding of dosage, the packaging of chlorine products, knowledge and skills for multipurpose laundry bleach, the taste of treated water, and reinforcement. This analysis suggests that a focus on these determinants and the household domain may help to improve the sustainability of future intervention efforts.

Effect of household-based drinking water chlorination on diarrhoea among children under five in Orissa, India: a double-blind randomised placebo-controlled trial

BACKGROUND

Boiling, disinfecting, and filtering water within the home can improve the microbiological quality of drinking water among the hundreds of millions of people who rely on unsafe water supplies. However, the impact of these interventions on diarrhoea is unclear. Most studies using open trial designs have reported a protective effect on diarrhoea while blinded studies of household water treatment in low-income settings have found no such effect. However, none of those studies were powered to detect an impact among children under five and participants were followed-up over short periods of time. The aim of this study was to measure the effect of in-home water disinfection on diarrhoea among children under five.

METHODS AND FINDINGS

We conducted a double-blind randomised controlled trial between November 2010 and December 2011. The study included 2,163 households and 2,986 children under five in rural and urban communities of Orissa, India. The intervention consisted of an intensive promotion campaign and free distribution of sodium dichloroisocyanurate (NaDCC) tablets during bi-monthly households visits. An independent evaluation team visited households monthly for one year to collect health data and water samples. The primary outcome was the longitudinal prevalence of diarrhoea (3-day point prevalence) among children aged under five. Weight-for-age was also measured at each visit to assess its potential as a proxy marker for diarrhoea. Adherence was monitored each month through caregiver's reports and the presence of residual free chlorine in the child's drinking water at the time of visit. On 20% of the total household visits, children's drinking water was assayed for thermotolerant coliforms (TTC), an indicator of faecal contamination. The primary analysis was on an intention-to-treat basis. Binomial regression with a log link function and robust standard errors was used to compare prevalence of diarrhoea between arms. We used generalised estimating equations to account for clustering at the household level. The impact of the intervention on weight-for-age z scores (WAZ) was analysed using random effect linear regression. Over the follow-up period, 84,391 child-days of observations were recorded, representing 88% of total possible child-days of observation. The longitudinal prevalence of diarrhoea among intervention children was 1.69% compared to 1.74% among controls. After adjusting for clustering within household, the prevalence ratio of the intervention to control was 0.95 (95% CI 0.79-1.13). The mean WAZ was similar among children of the intervention and control groups (-1.586 versus -1.589, respectively). Among intervention households, 51% reported their child's drinking water to be treated with the tablets at the time of visit, though only 32% of water samples tested positive for residual chlorine. Faecal contamination of drinking water was lower among intervention households than controls (geometric mean TTC count of 50 [95% CI 44-57] per 100 ml compared to 122 [95% CI 107-139] per 100 ml among controls [p<0.001] [n = 4,546]).

CONCLUSIONS

Our study was designed to overcome the shortcomings of previous double-blinded trials of household water treatment in low-income settings. The sample size was larger, the follow-up period longer, both urban and rural populations were included, and adherence and water quality were monitored extensively over time. These results provide no evidence that the intervention was protective against diarrhoea. Low compliance and modest reduction in water contamination may have contributed to the lack of effect. However, our findings are consistent with other blinded studies of similar interventions and raise additional questions about the actual health impact of household water treatment under these conditions.

TRIAL REGISTRATION

ClinicalTrials.govNCT01202383 Please see later in the article for the Editors' Summary.

High adherence is necessary to realize health gains from water quality interventions

Background

Safe drinking water is critical for health. Household water treatment (HWT) has been recommended for improving access to potable water where existing sources are unsafe. Reports of low adherence to HWT may limit the usefulness of this approach, however.

Methods and Findings

We constructed a quantitative microbial risk model to predict gains in health attributable to water quality interventions based on a range of assumptions about pre-treatment water quality; treatment effectiveness in reducing bacteria, viruses, and protozoan parasites; adherence to treatment interventions; volume of water consumed per person per day; and other variables. According to mean estimates, greater than 500 DALYs may be averted per 100,000 person-years with increased access to safe water, assuming moderately poor pre-treatment water quality that is a source of risk and high treatment adherence (>90% of water consumed is treated). A decline in adherence from 100% to 90% reduces predicted health gains by up to 96%, with sharpest declines when pre-treatment water quality is of higher risk.

Conclusions

Results suggest that high adherence is essential in order to realize potential health gains from HWT.

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).

Impact of integration of hygiene kit distribution with routine immunizations on infant vaccine coverage and water treatment and handwashing practices of Kenyan mothers

Integration of immunizations with hygiene interventions may improve use of both interventions. We interviewed 1361 intervention and 1139 comparison caregivers about hygiene practices and vaccination history, distributed water treatment and hygiene kits to caregivers during infant vaccination sessions in intervention clinics for 12 months, and conducted a followup survey of 2361 intervention and 1033 comparison caregivers. We observed significant increases in reported household water treatment (30% vs 44%, P < .0001) and correct handwashing technique (25% vs 51%, P < .0001) in intervention households and no changes in comparison households. Immunization coverage improved in both intervention and comparison infants (57% vs 66%, P = .04; 37% vs 53%, P < .0001, respectively). Hygiene kit distribution during routine immunizations positively impacted household water treatment and hygiene without a negative impact on vaccination coverage. Further study is needed to assess hygiene incentives, implement alternative water quality indicators, and evaluate the impact of this intervention in other settings.

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.

Antibiotic susceptibility of thermo-tolerant Escherichia coli 2 isolated from drinking water of Khairpur City, Sindh, Pakistan

A total 72 drinking water sample were collected and analyzed by membrane filtration method during 1 year study from various points in Khairpur City. Out of these 58 (80.55%) samples were found to be contaminated with thermo-tolerant Escherichia coli 2. The susceptibility of these isolates to 35 antibiotics was studied by disc diffusion method and the organism was highly sensitive to levoflaxin, cefipime, enoxobid, noroxin, tarivid, ciproxin, avelox, amikacin, kanamycin, rocifin, pipenedic acid and slightly sensitive to cravit, naladixic acid, neomycin, cefizox, fortum cefotaxime, cefizox, fortum, tobramycin and cefoperoxone. The resistance against 16 antibiotics such as meropenem, linkomycin, fusidic acid, orbenin, penicillin, streptomycin, bacitracin, minocin, zinacef, amoxil, ceclor, claracid, cephalexin, augmentin, cephradin and dalacin was shown by these isolates. We report the presence of multi-drug resistance in thermo-tolerant Escherichia coli isolated in municipal water with different levels of prevalence in Khairpur City. In this study a higher number of positive results were obtained in all sampling points indicating the more fecally polluted municipal water.

Risk factors for typhoid in Darjeeling, West Bengal, India: evidence for practical action

OBJECTIVE

To identify risk factors for typhoid and propose prevention measures.

METHODS

Case-control study; we compared hospital-based typhoid cases defined as fever>38 degrees C for >or=3 days with four-fold rise in 'O' antibodies on paired sera (Widal) with community, age and neighbourhood matched controls. We obtained information on drinking water, fruits, vegetables, milk products and sanitation; and calculated matched odds ratios (MOR) and attributable fractions in the population (AFP) for the risk factors or failure to use prevention measures.

RESULTS

The 123 typhoid cases (median age: 25 years, 47% female) and 123 controls did not differ with respect to baseline characteristics. Cases were less likely to store drinking water in narrow-mouthed containers (MOR: 0.4, 95% CI: 0.2-0.7, AFP 29%), tip containers to draw water (MOR: 0.4, 95% CI: 0.2-0.7, AFP 33%) and have home latrines (MOR: 0.5, 95% CI: 0.3-0.8, AFP 23%). Cases were more likely to consume butter (OR: 2.3, 95% CI: 1.3-4.1, AFP 28%), yoghurt (OR: 2.3, 95% CI: 1.4-3.7, AFP 34%) and raw fruits and vegetables, including onions (MOR: 2.1, 95% CI: 1.2-3.9, AFP 34%), cabbages (OR: 2.8, 95% CI: 1.7-4.8, AFP 44%) and unwashed guavas (OR: 1.9, 95% CI: 1.2-3, AFP 25%).

CONCLUSION

Typhoid was associated with unsafe water and sanitation practices as well as with consumption of milk products, fruits and vegetables. We propose to chlorinate drinking water at the point of use, wash/cook raw fruits and vegetables and ensure safer preparation/storage of local milk products.

Sustainable colloidal-silver-impregnated ceramic filter for point-of-use water treatment

Cylindrical colloidal-silver-impregnated ceramic filters for household (point-of-use) water treatment were manufactured and tested for performance in the laboratory with respect to flow rate and bacteria transport. Filters were manufactured by combining clay-rich soil with water, grog (previously fired clay), and flour, pressing them into cylinders, and firing them at 900 degrees C for 8 h. The pore-size distribution of the resulting ceramic filters was quantified by mercury porosimetry. Colloidal silver was applied to filters in different quantities and ways (dipping and painting). Filters were also tested without any colloidal-silver application. Hydraulic conductivity of the filters was quantified using changing-head permeability tests. [3H]H2O water was used as a conservative tracer to quantify advection velocities and the coefficient of hydrodynamic dispersion. Escherichia coli (E. coli) was used to quantify bacterial transport through the filters. Hydraulic conductivity and pore-size distribution varied with filter composition; hydraulic conductivities were on the order of 10(-5) cm/s and more than 50% of the pores for each filter had diameters ranging from 0.02 to 15 microm. The filters removed between 97.8% and 100% of the applied bacteria; colloidal-silver treatments improved filter performance, presumably by deactivation of bacteria. The quantity of colloidal silver applied per filter was more important to bacteria removal than the method of application. Silver concentrations in effluent filter water were initially greater than 0.1 mg/L, but dropped below this value after 200 min of continuous operation. These results indicate that colloidal-silver-impregnated ceramic filters, which can be made using primarily local materials and labor, show promise as an effective and sustainable point-of-use water treatment technology for the world's poorest communities.

Diarrhoea prevention in a high-risk rural Kenyan population through point-of-use chlorination, safe water storage, sanitation, and rainwater harvesting

Lack of access to safe water and sanitation contributes to diarrhoea moribidity and mortality in developing countries. We evaluated the impact of household water treatment, latrines, shallow wells, and rainwater harvesting on diarrhoea incidence in rural Kenyan children. We compared diarrhoea rates in 960 children aged <5 years in 556 households in 12 randomly selected intervention villages and six randomly selected comparison villages during weekly home visits over an 8-week period. On multivariate analysis, chlorinating stored water [relative risk (RR) 0.44, 95% confidence interval (CI) 0.28-0.69], latrine presence (RR 0.71, 95% CI 0.54-0.92), rainwater use (RR 0.70, 95% CI 0.52-0.95), and living in an intervention village (RR 0.31, 95% CI 0.23-0.41), were independently associated with lower diarrhoea risk. Diarrhoea risk was higher among shallow well users (RR 1.78, 95% CI 1.12-2.83). Chlorinating stored water, latrines, and rainwater use all decreased diarrhoea risk; combined interventions may have increased health impact.

Bringing safe water to remote populations: an evaluation of a portable point-of-use intervention in rural Madagascar

Rural populations disproportionately lack access to improved water supplies. We evaluated a novel scheme that employed community-based sales agents to disseminate the Safe Water System (SWS)--a household-level water chlorination and safe storage intervention--in rural Madagascar. Respondents from 242 households in 4 villages were interviewed; all used surface water for drinking water. Respondents from 239 households (99%) had heard of Sûr'Eau, the SWS disinfectant; 226 (95%) reported having ever used Sûr'Eau, and 166 (73%) reported current use. Current Sûr'Eau use was confirmed in 54% of households. Community sales agents effectively motivated their neighbors to adopt a new health behavior that prevents diarrhea. Future work should focus on strategies for sustaining SWS use, factors that motivate community-based sales agents to promote SWS, and the feasibility of scaling up this approach.

Effect of point-of-use disinfection, flocculation and combined flocculation-disinfection on drinking water quality in western Kenya

AIMS

Point-of-use drinking water disinfection with sodium hypochlorite has been shown to improve water quality and reduce diarrhoeal disease. However, the chlorine demand of highly turbid water may render sodium hypochlorite less effective.

METHODS AND RESULTS

We evaluated a novel combined flocculant-disinfectant point-of-use water treatment product and compared its effect on drinking water quality with existing technologies in western Kenya. In water from 30 sources, combined flocculant-disinfectant reduced Escherichia coli concentrations to <1 CFU100 ml(-1) for 29 (97%) and reduced turbidity to <5 nephelometric turbidity units (NTU) for 26 (87%). By contrast, water from 30 sources treated with sodium hypochlorite reduced E. coli concentrations to <1 CFU 100 ml(-1) for 25 (83%) and turbidity to <5 NTU for 5 (17%).

CONCLUSIONS

For source waters over a range of turbidities in western Kenya, combined flocculant-disinfectant product effectively reduces turbidity to <5 NTU and reduces E. coli concentrations to <1 CFU 100 ml(-1).

SIGNIFICANCE AND IMPACT OF THE STUDY

The novel flocculant-disinfectant product may be acceptable to consumers and may be effective in reducing diarrhoeal disease in settings where source water is highly turbid.

Changing community behaviour: experience from three African countries

In the developing world, more than 1 billion people lack access to safe water. To address this problem, the US Centers for Disease Control and Prevention developed the Safe Water System (SWS), a household-based intervention with three elements: water disinfection, safe storage and behaviour change techniques, and tested these in three countries. In Zambia, social marketing (SM) was used to implement the SWS, and 100 randomly selected households also received motivational interviewing (MI). In Madagascar, the SWS was implemented using SM and community mobilisation (CM). In rural Western Kenya, the SWS was also implemented with SM and CM. In Zambia, 3 months after the SM project launch, 14% of households in the SM-only group had adopted the disinfectant compared with 78% of households in the SM plus MI group. Through SM, over 1 million bottles of disinfectant were sold in 3 years in Zambia. In Antananarivo, Madagascar, 6 months after launch of the water disinfectant, 8% of households in an early stage of the CM process were using the disinfectant compared with 20% in households at a late stage of the CM process. In 1 year, over 500,000 bottles of disinfectant were sold in Madagascar. In Kenya, adoption of the water disinfectant exceeded 60% in intervention households and diarrhoea rates decreased by 58% in children < 5 years. Social marketing permits widespread dissemination of interventions, but may have limited penetration into economically disadvantaged communities. Additional, targeted interventions, such as MI and CM, can increase product adoption. A combination of behaviour change interventions can increase project impact.

Is drinking water in Abidjan, Côte d'Ivoire, safe for infant formula?

OBJECTIVE

To survey knowledge, attitudes, and practices regarding water use and infant feeding in the Koumassi District of Abidjan, Côte d'Ivoire, and to evaluate the microbiologic quality of source and stored drinking water.

DESIGN

Random-cluster household survey.

METHODS

We randomly selected 20 clusters, each comprising six households with at least 1 child aged < or =3 years. In each household, we administered a questionnaire and collected source and stored drinking water samples and tested these for chlorine levels and for total coliform and fecal bacteria count ( Escherichia coli ).

RESULTS

Municipal water was used for drinking in 112 (93%) of 120 households, and in 99 (83%), it was stored for later use. By 1 month of age, 97 (90%) of 108 infants given drinking water were given stored water for drinking. In 8 (66%) of 12 households where children were receiving artificial feeding, formula was prepared from municipal water without additional treatment. Stored water had lower levels of free chlorine than source water (median of 0.05 versus 0.2 mg/dl; p <.001), and E. coli was detected in 36 (41%) of 87 stored water samples and 1 (1%) of 108 source water samples ( p <.001).

CONCLUSIONS

In the Koumassi District of Abidjan, where municipal water is widely available and of good quality, drinking water is stored in most households, is often contaminated with E. coli, and is given to children at a young age. If replacement feeding is to be more widely used to prevent postnatal transmission of HIV-1, communities using stored water need interventions to make stored water safer.

Not just a drop in the bucket: expanding access to point-of-use water treatment systems

Since 1990, the number of people without access to safe water sources has remained constant at approximately 1.1 billion, of whom approximately 2.2 million die of waterborne disease each year. In developing countries, population growth and migrations strain existing water and sanitary infrastructure and complicate planning and construction of new infrastructure. Providing safe water for all is a long-term goal; however, relying only on time- and resource-intensive centralized solutions such as piped, treated water will leave hundreds of millions of people without safe water far into the future. Self-sustaining, decentralized approaches to making drinking water safe, including point-of-use chemical and solar disinfection, safe water storage, and behavioral change, have been widely field-tested. These options target the most affected, enhance health, contribute to development and productivity, and merit far greater priority for rapid implementation.