E. coli from dishcloths as an indicator of hygienic status in households. Journal of Water, Sanitation and Hygiene for Development In Press, 2015 | doi:10.2166/washdev.2015.119

Authors: V. Keshav, A. Mathee, N. Naicker, A. Swart and T. G. Barnard

E. coli is routinely used as an indicator of fecal pollution although some strains are capable of causing diarrhea. E. coli was used as a model organism for this study to assess the possibility that dishcloths used in households could contribute to the occurrence of diarrhea. Dishcloths (n = 424) were collected from five suburbs in Johannesburg (South Africa) as part of a larger Health, Environment & Development (HEAD) study. Results for the total coliforms indicated that on average 81% of the samples analyzed had total coliform counts of more than 1,000 cfu/100 ml per 25 cm2 cloth.

The E. coli results indicated that 40% of the samples had culturable E. coli present with 17% of the samples showing the presence of >1,000 cfu/100 ml per 25 cm2 cloth. Except for the samples from Bertrams all the pathogenic E. coli genes could be detected in various combinations in the different samples. Since all the diarrheagenic E. coli strains detected can be accepted as culturable due to the enrichment step, there is a clear danger of contamination of food and surfaces exposed to the contaminated dishcloths. The results indicated that there is a need for public education regarding hygiene in the households, especially if the same dishcloth is used for various tasks.

Effect of common rooftop materials as support base for solar disinfection (SODIS) in rural areas under temperate climates. Solar Energy, May 2015.

Authors: M. Vivaa, M. Fuentes, J. Castro, R. García-Pacheco

Highlights

  • Metal roofing and bamboo vegetable cover were studied as support materials for SODIS.
  • Metal covers enhance SODIS due to high reflectivity & heat transfer properties.
  • Maximum water temperatures differences in the bottles were of about 2.5 °C.
  • SODIS processes starting at midday achieved faster inactivation.

Two common rooftop materials easily found in rural areas – zinc-coated metal sheet and bamboo cover – were studied to analyse their possible influence in the solar disinfection process by affecting the received UV radiation and water temperature in SODIS plastic bottles. The objective is to use available local materials to enhance the process while reducing the extra energy usage required for the manufacturing of new ad-hoc systems.

Experiments were conducted at a temperate climate, 40 °N latitude, over different seasons of the year. Escherichia coli and total coliforms disinfection processes were studied. Results show that in most cases the bottles over the zinc-coated metal roofing material reached an inactivation level of 1-log higher than those on the bamboo cover. Maximum water temperatures differences in the bottles over the two materials were of about 2.5 °C in the best case. Higher inactivation in the zinc-coated metal sheet when water temperature is below 40 °C should be attributed to better material reflectivity. At water temperatures around 40 °C, the 2.5 °C difference can be significative and accelerate the disinfection process.

Material heat transfer characteristics have been also found to be essential, especially when the solar disinfection starts at mid-day instead of early in the morning. In this case, as the support materials are already at higher temperatures because of solar irradiance absorption, the water temperature in the bottles increases more rapidly, contributing to the water disinfection process when it rises above 40 °C.

Eliminating Diseases by Investing in WASH. Huffington Blog, May 2015.

Author: Neeraj Mistry, anaging Director for the Global Network for Neglected Tropical Diseases.

At the turn of the century, world leaders came together at the United Nations in New York to develop the Millennium Development Goals (MDGs), a set of eight ambitious goals and targets meant to significantly reduce poverty by the year 2015. As the window to achieve these goals closes this year, we reflect on progresses made and look ahead to the sustainable development goals (SDGs) that will shape the development agenda for the next 15 years.

A number of MDG targets have already been met, including efforts to reduce cases of HIV/AIDS, malaria and other diseases (MDG 6) and improving access to safe drinking water (MDG 7). Moving forward, addressing neglected tropical diseases (NTDs) will be a critical component when working toward meeting both of these goals. NTDs are bacterial, parasitic and viral infections that affect the most marginalized communities across the world and are often the result of inadequate water supply, limited access to sanitation facilities and poor hygiene. Areas with stagnant water are breeding grounds for insects that carry NTDs, notably mosquitoes which transmit malaria, but also dengue fever, lymphatic filariasis and chikungunya. By promoting integrated vector management and improved water control measures in endemic countries, we can simultaneously work to combat HIV/AIDS and malaria, while also working to control and eliminate NTDs.

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Handwashing before drawing water: a sixth critical time? Waterlines, Apr 2015.

Author: Sally Sutton

The promotion of critical times for handwashing has done much to improve knowledge on hygiene, even if rather less on the practice. However while there has long been a recognition of the need to wash hands before preparing food, there has never been any mention of taking the same precautions before drawing water.

With almost half of rural Africa still taking water either by bucket and rope or by scooping water from surface and shallow ground water, lack of handwashing can not only lead to contamination of the water being carried home, but also of the source itself, as demonstrated by source water quality monitoring detailed in this paper.

Even for those taking water from better protected sources, dirty hands can lead to contamination of collected water, especially where bowls and buckets are the main vessels for water transport. Handwashing before water collection is proposed as an additional barrier to faecal-oral contamination, to make a sixth critical time.

Association of Supply Type with Fecal Contamination of Source Water and Household Stored Drinking Water in Developing Countries: A Bivariate Meta-analysis. Env Health Perspec, May 2015.

Authors: Katherine F. Shields, Robert E.S. Bain, Ryan Cronk, Jim A. Wright, and Jamie Bartram

Background: Access to safe drinking water is essential for health. Monitoring access to drinking water focuses on water supply type at the source, but there is limited evidence on whether quality differences at the source persist in water stored in the household.

Objectives: To assess the extent of fecal contamination at the source and in household storedwater (HSW) and explore the relationship between contamination at each of these sampling points and water supply type.

Methods: A bivariate random-effects meta-analysis of 45 studies, identified through asystematic review, that reported either the proportion of samples free of fecal indicator bacteria and/or individual sample bacteria counts for source and HSW, disaggregated by supply type.

Results: Water quality deteriorated substantially between source and stored water. Mean percentage of contaminated samples (noncompliance) at the source was 46% (95% CI: 33, 60%) while mean noncompliance in HSW was 75% (95% CI: 64, 84%). Water supply type was significantly associated with noncompliance at the source (p < .001) and in HSW (p = 0.03). Source water (OR = 0.2; 95% CI: 0.1, 0.5) and HSW (OR = 0.3; 95% CI: 0.2, 0.8) from pipedsupplies had significantly lower odds of contamination when compared to non-piped water,potentially due to residual chlorine.

Conclusions: Piped water is less likely to be contaminated compared to other water supply typesat both the source and in HSW. A focus on upgrading water services to piped supplies may helpimprove safety, including for those drinking stored water.

Accuracy, precision, usability, and cost of free chlorine residual testing methods. Journal of Water and Health Vol 13 No 1 pp 79–90 © IWA Publishing 2015 doi:10.2166/wh.2014.195.

Authors: Anna Murray and Daniele Lantagne

Chlorine is the most widely used disinfectant worldwide, partially because residual protection is maintained after treatment. This residual is measured using colorimetric test kits varying in accuracy, precision, training required, and cost. Seven commercially available colorimeters, color wheel and test tube comparator kits, pool test kits, and test strips were evaluated for use in low-resource settings by: (1) measuring in quintuplicate 11 samples from 0.0–4.0 mg/L free chlorine residual in laboratory and natural light settings to determine accuracy and precision; (2) conducting volunteer testing where participants used and evaluated each test kit; and (3) comparing costs.

Laboratory accuracy ranged from 5.1–40.5% measurement error, with colorimeters the most accurate and test strip methods the least. Variation between laboratory and natural light readings occurred with one test strip method. Volunteer participants found test strip methods easiest and color wheel methods most difficult, and were most confident in the colorimeter and least confident in test strip methods. Costs range from 3.50–444 USD for 100 tests. Application of a decision matrix found colorimeters and test tube comparator kits were most appropriate for use in low-resource settings; it is recommended users apply the decision matrix themselves, as the appropriate kit might vary by context.

Microbial quality of domestic water: following the contamination chain in a rural township in Kenya. Journal of Water, Sanitation and Hygiene for Development Vol 5 No 1 pp 39–49 © IWA Publishing 2015 doi:10.2166/washdev.2014.070

Authors: Pauline W. Macharia, Paul T. Yillia, Wairimu A. Muia, Denis Byamukama and Norbert Kreuzinger

A study was undertaken in Njoro Township, Kenya to evaluate the extent to which drinking water was subjected to post-collection faecal contamination in low-income and high-income households. Boreholes were the main drinking water sources, accounting for roughly 70% singular access. The microbial quality of drinking water from the boreholes deteriorated from the point-of-collection through conveying containers of small-scale water vendors to household storage containers, irrespective of their income status.

The densities of Escherichia coli (EC) were relatively low at the point-of-collection – median (M): 18 CFU/100 mL, range (R): 0–220, n = 60 – increasing considerably in the containers of water vendors (M: 290 CFU/100 mL, R: 30–350) and slightly (M: 360 CFU/100 mL, R: 0–520) between vendors and low-income households, many of whom used the services of vendors unlike high-income households who relied on a piped system on premises (M: 40 CFU/100 mL, R: 0–500). Post-collection contamination was high in low-income households compared to high-income households but differences were not significant between the two household categories with and without household water treatment (HWT).

Different HWT methods in the two household categories significantly reduced faecal contamination, but unhygienic handling and poor storage practices afterwards caused recontamination. HWT and behavioural change measures need not selectively target household groups solely on the basis of their income status.

Development of improved low-cost ceramic water filters for viral removal in the Haitian contextJournal of Water, Sanitation and Hygiene for Development Vol 5 No 1 pp 28–38 © IWA Publishing 2015 doi:10.2166/washdev.2014.121.

Authors: L. Guerrero-Latorre, M. Rusiñol, A. Hundesa, M. Garcia-Valles, S. Martinez, O. Joseph, S. Bofill-Mas and R. Girones

Household-based water treatment (HWT) is increasingly being promoted to improve water quality and, therefore, health status in low-income countries. Ceramic water filters (CWFs) are used in many regions as sustainable HWT and have been proven to meet World Health Organization (WHO) microbiological performance targets for bacterial removal (2–4 log); however, the described viral removal efficiencies are insufficient to significantly reduce the associated risk of viral infection. With the objective of improving the viral removal efficiencies of ceramic water filters, new prototypes with different oxide compositions and firing atmospheres have been developed and evaluated.

For removal efficiencies human adenoviruses, MS2 bacteriophage and Escherichia coli were quantified in all prototypes. A new model of CWF that was fired in a reductive atmosphere presented virus and bacteria removal efficiencies greater than 3.0 log and 2.5 log, respectively, which would fulfill the viral targets that are recommended by the WHO. Ceramic characterization of the selected filters, which were fired in a reductive atmosphere, showed that a larger specific surface area than those of control filters and higher fraction of a positive Z-potential fraction are the most likely explanations for this increase in virus removal.

Fouling in hollow fiber membrane microfilters used for household water treatmentJournal of Water, Sanitation and Hygiene for Development In Press, Uncorrected Proof © IWA Publishing 2015  |  doi:10.2166/washdev.2015.206

Authors: Anna Murray, Mario Goeb, Barbara Stewart, Catherine Hopper, Jamin Peck, Carolyn Meub, Ayse Asatekin and Daniele Lantagne

The Sawyer PointOne hollow fiber membrane microfilter is promoted for household water treatment in developing countries. Critical limitations of membrane filtration are reversible and irreversible membrane fouling, managed by backwashing and chemical cleaning, respectively. The PointOne advertised lifespan is 10 years; users are instructed to backwash as maintenance. Owing to reduced turbidity and bacterial removal efficiencies, six PointOnes were removed from Honduran homes after 23 months of use. In the laboratory, we tested sterile water filtrate for turbidity and bacterial presence before and after backwashing and chemical cleaning. Sterile water filtrate from uncleaned filters had turbidity of 144–200 NTU and bacteria counts of 13–200 CFU. Cleaned filter effluent was positive for total coliforms.

On one new and one used, cleaned filter, we imaged membranes with scanning electron microscopy and characterized surface elemental compositions with spectroscopy. Images and spectroscopy of the used, cleaned membrane revealed a dense, cake fouling layer consisting of inorganic metal oxides, organic material, and biofouling. Burst fibers were visually observed. This PointOne was thus irreversibly fouled and non-functional after <2 years of use. Further research is recommended to determine: impacts of source water quality on PointOne performance, a cleaning regimen to manage fouling, and an appropriate filter lifespan.

The Short- and Medium-Term Impacts of Household Water Supply and Sanitation on Diarrhea in Rural India, April 2015. Maryland Population Research Center Working Paper.

Authors: Esther Duflo, Michael Greenston, Raymond Guiteras, Thomas Clasen.

Poor water quality and sanitation lead to severe health problems in developing countries, yet there is little evidence on the effectiveness of at-scale, infrastructure-based solutions for the rural poor. This paper estimates the impact of an integrated water and sanitation improvement program in rural India that provided household-level water connections, latrines, and bathing facilities to all households in approximately 100 villages. We employ an interrupted time-series analysis with multiple units to estimate the short- and medium-term impacts of the intervention on episodes of diarrhea for which treatment was received. The estimates suggest that the intervention was effective, reducing such episodes by 30-50%. These results are evident in the short term and persist for 5 years or more. The annual cost is approximately US$60 per household, as compared to annual household consumption of approximately US$740.