Access to potable water is a priority for highly-marginalized rural communities of Chiapas, Mexico where consumption of poorly sanitized water has fostered severe diarrheal diseases among children. Interventions aimed to reduce contaminants present in water are necessary to reduce morbidity and mortality rates. In this work we evaluated the efficiency of a point of use water purification system, Llaveoz, to eradicate total coliform (TC) bacteria and diarrheagenic E. coli (DEC) strains in 62 paired water samples obtained from households during the dry and rainy season. TC was determined by the membrane filtration method whereas DEC strains were evaluated by a multiplex PCR approach. After Llaveoz treatment, water samples collected during the dry season (N=20) had an 80.3% reduction of TC counts (p<0.05). Similarly, TC were significantly reduced (72.3%, (p<0.05)) in water samples treated during the rainy season (N=42). A total of 28 E. coli strains were isolated of which 14.3% (N=4) were identified as DEC strains (ETEC (N=2), EAEC (N=1) or EIEC (N=1)) in untreated water samples. Llaveoz-treated water did not contain DEC strains. Thus, the Llaveoz system represents an alternative method to obtain more pure water in regions where potable water sources are not available.
KeywordsChiapas; Diarrheagenic E. coli; Llaveoz; Water purification system defecation is a common practice among inhabitants of Oxchuc and other marginalized municipalities of Chiapas, water sources are prone to contamination by feces containing bacterial pathogens associated with water-borne diseases. This may account for the documented high mortality rates due to diarrheal diseases in the area [2,3].In order to improve water quality in resources-limited regions, affordable methods to disinfect water need to be engineered. Water for human consumption must have an appropriate quality in order to prevent and avoid transmission of gastrointestinal pathogens [5]. These systems should demonstrate effectiveness in removing potential human pathogens from water samples such as the presence of E. coli strains, a biological indicator of fecal contamination. Thus, the objective of this study was to evaluate the efficacy of a UV radiation-based water disinfection system, hereafter called Llaveoz, to eliminate total coliforms and pathogenic E. coli strains, in water utilized for human consumption in a rural zone of Chiapas, Mexico.
Materials and Methods
Study zoneThis study was carried out in the Lelenchij locality, Oxchuc, Chiapas, Mexico, which is located at 1,900 meters above the sea level, in the Altos Tsotsil Tseltal zone. The community had 807 inhabitants in 2013, 99.8% of which do not have access to health care services. Their houses in general have electricity (94.3%) but 99.2% and 86.5% of them do not have sources of potable water and sewage, respectively and 41.4% of households have earthen floor [6].
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Llaveoz water disinfection systemThe Llaveoz™ water disinfection system (patent US2011/0215037 A1) consists in a plastic faucet which is pla...