Solar disinfection of drinking water protects against cholera in children under 6 years of age.
ABSTRACT We have previously reported a reduction in risk of diarrhoeal disease in children who used solar disinfected drinking water. A cholera epidemic, occurring in an area of Kenya in which a controlled trial of solar disinfection and diarrhoeal disease in children aged under 6 had recently finished, offered an opportunity to examine the protection offered by solar disinfection against cholera.
In the original trial, all children aged under 6 in a Maasai community were randomised by household: in the solar disinfection arm, children drank water disinfected by leaving it on the roof in a clear plastic bottle, while controls drank water kept indoors. We revisited all households which had participated in the original trial.
There were 131 households in the trial area, of which 67 had been randomised to solar disinfection (a further 19 households had migrated as a result of severe drought). There was no significant difference in the risk of cholera in adults or in older children in households randomised to solar disinfection; however, there were only three cases of cholera in the 155 children aged under 6 years drinking solar disinfected water compared with 20 of 144 controls.
Results confirm the usefulness of solar disinfection in reducing risk of water borne disease in children. Point of consumption solar disinfection can be done with minimal resources, which are readily available, and may be an important first line response to cholera outbreaks. Its potential in chorine resistant cholera merits further investigation.
Full-textDOI: · Available from: Ronán Michael Conroy, Sep 26, 2015
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- "Wegerlin and Sommer (1996) developed SODIS (Solar water Disinfection) and SOPA (Solar Pasteurization) methods which are based on the synergistic effects of UV rays and heat treatment of water by infrared heat. Water disinfection using the solar disinfection (SODIS) process relies on the synergistic effect of sunlight and temperature upon bacteria (Conroy et al. 2001; Reed 2004). A great part of the research in understanding the mechanism of this process has been done using transparent plastic bottles exposed to sunlight under different operating conditions. "
ABSTRACT: Objectives: The influence of abiotic factors of water which may affect Artemesia annua (A. annua) efficiency as a disinfectant is not clearly elucidated. This study aimed to assess the potential effects of various water pH values of the infusion of A. annua leaves extract on some bacteria of hygiene and sanitary evaluation. Methodology and Results: A. annua leaves were collected in Bangante (West region, Cameroon) and bacteria were isolated from the surface water (lotic hydrosystems) in Yaoundé (Cameroon, Central Africa). The bacteria used were S. paratyphi, S. aureus and E. coli. Experiments were carried out in aquatic microcosms under dark conditions. The pH values considered were 4, 5, 6, 7, 8 and 9. These values were adjusted using diluted HCl and NaOH. The results showed the temporal changes of cell abundance from one bacteria species to another with respect to the pH value in one hand, and also with respect to the number of cell species in solution on the other hand. In monospecific culture condition, the extract of A. annua seemed to appear as a source of carbon and energy for bacteria growth. In mixed cultures the influence of pH in the presence of the extract of A. annua in the dark seemed to foster trophic relations among bacteria in some cases and stimulate the production of inhibitory substances in other cases. Conclusions and application of findings: Molecules contained in the extract of A. annua were potentially implicated in the physical and chemical changes of the medium, enabling the cell growth observed. A. annua extract did not have a significant bacterial inhibitory property in the water in the darkness. Although A. annua extract is often used as antibacterial component, it should not be used in the bacteriological treatment of drinking water under dark condition whether the water pH is acidic, neutral or alkaline.03/2013; 62:4595. DOI:10.4314/jab.v62i0.86071
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- "Field trials have demonstrated a significant health benefits from consumption of SODIS treated water  . The effectiveness of SODIS against cholera was also demonstrated in a Kenyan health impact assessment, where an 86% reduction cholera cases was observed in households regularly using SODIS . Studies to improve the efficiency of the SODIS process using low-cost, commonly available materials have been conducted    ; however, the simple approach of exposing a 2 L PET bottle to full sun for a minimum of 6 hours is the most commonly promoted and practiced method. "
ABSTRACT: It is estimated that 884 million people lack access to improved water supplies. Many more are forced to rely on supplies that are microbiologically unsafe, resulting in a higher risk of waterborne diseases, including typhoid, hepatitis, polio, and cholera. Due to poor sanitation and lack of clean drinking water, there are around 4 billion cases of diarrhea each year resulting in 2.2 million deaths, most of these are children under five. While conventional interventions to improve water supplies are effective, there is increasing interest in household-based interventions to produce safe drinking water at an affordable cost for developing regions. Solar disinfection (SODIS) is a simple and low cost technique used to disinfect drinking water, where water is placed in transparent containers and exposed to sunlight for 6 hours. There are a number of parameters which affect the efficacy of SODIS, including the solar irradiance, the quality of the water, and the nature of the contamination. One approach to SODIS enhancement is the use of semiconductor photocatalysis to produce highly reactive species that can destroy organic pollutants and inactivate water pathogens. This paper presents a critical review concerning semiconductor photocatalysis as a potential enhancement technology for solar disinfection of water.International Journal of Photoenergy 01/2011; 12. DOI:10.1155/2011/798051 · 1.56 Impact Factor
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- "The deleterious effect of solar radiation on enteric bacteria is used to improve microbiological drinking water quality by solar disinfection (SODIS), a simple drinking water treatment method (Wegelin et al., 1994). A positive impact on health has been documented in several epidemiological studies, e.g. during a cholera epidemic in Kenya, where a reduction of diarrhoea cases among SODIS users of 88% was observed (Conroy et al., 2001). SODIS was recently added to the WHO list of recommend drinking water treatment methods. "
ABSTRACT: Solar disinfection (SODIS) is a simple drinking water treatment method that improves microbiological water quality where other means are unavailable. It makes use of the deleterious effect of solar irradiation on pathogenic microbes and viruses. A positive impact on health has been documented in several epidemiological studies. However, the molecular mechanisms damaging cells during this simple treatment are not yet fully understood. Here we show that protein damage is crucial in the process of inactivation by sunlight. Protein damages in UVA-irradiated Escherichia coli cells have been evaluated by an immunoblot method for carbonylated proteins and an aggregation assay based on semi-quantitative proteomics. A wide spectrum of structural and enzymatic proteins within the cell is affected by carbonylation and aggregation. Vital cellular functions like the transcription and translation apparatus, transport systems, amino acid synthesis and degradation, respiration, ATP synthesis, glycolysis, the TCA cycle, chaperone functions and catalase are targeted by UVA irradiation. The protein damage pattern caused by SODIS strongly resembles the pattern caused by reactive oxygen stress. Hence, sunlight probably accelerates cellular senescence and leads to the inactivation and finally death of UVA-irradiated cells.Environmental Microbiology 11/2010; 12(11-11):2931-45. DOI:10.1111/j.1462-2920.2010.02268.x · 6.20 Impact Factor