A series of experiments is reported to identify and characterize the inactivation process in oper... more A series of experiments is reported to identify and characterize the inactivation process in operation when drinking water, heavily contaminated with a Kenyan isolate of Escherichia coli, is stored in transparent plastic bottles that are then exposed to sunlight. The roles of optical and thermal inactivation mechanisms are studied in detail by simulating conditions of optical irradiance, water turbidity and temperature, which were recorded during a series of solar disinfection measurements carried out in the Kenyan Rift Valley. Optical inactivation effects are observed even in highly turbid water (200 ntu) and at low irradiances of only 10 mW cm −2. Thermal inactivation is found to be important only at water temperatures above 45°C, at which point strong synergy between optical and thermal inactivation processes is observed. The results confirm that, where strong sunshine is available, solar disinfection of drinking water is an effective, low cost method for improving water quality and may be of particular use to refugee camps in disaster areas. Strategies for improving bacterial inactivation are discussed.
Abstract Hand hygiene (HH) is the most significant factor for the improvment of practices and red... more Abstract Hand hygiene (HH) is the most significant factor for the improvment of practices and reduction of microorganism transmission to patients, visitors, and health care workers, yet compliance rates remaining low. This study aims to improve the compliance of intensive care unit (ICU) staff in hand disinfection; either by washing or rubbing with alcohol-based solution. We analysised the HH compliance of ICU staff at Al-Istishari hospital in Jordan over a period of four months (December 2008-April 2009). A total of 24 study participants were observed to have a high ratio of HH compliance rate after removing gloves (76%). This prospective, interventional study employed an exploratory mixed qualitative-quantitative method. The study was conducted between December 2008 and April 2009 in the ICU at Al-Istishari Hospital, Amman, Jordan. The Hand Washing Questionnaire (HWQ) and 80 h of observations were used to measure and evaluate the compliance of HH practices among ICU employees. The...
Stool samples were collected during August 1994 from seventy rural Maasai children under the age ... more Stool samples were collected during August 1994 from seventy rural Maasai children under the age of five years who were living in the Maasailand region of the Kenyan Rift Valley. Microbiological analysis was carried out on these samples to identify which intestinal pathogens were present among the infant population of the Maasai. Of the samples studied 54% were pathogen positive. The most common pathogen isolated was Giardia lamblia which was detected in 31% of the samples. Other pathogens that were detected include: Entamoeba histolytica (23%), Enteropathogenic Escherichia coli (13%), Strongyloides stercoralis (4%), Blastocystis hominis (3%) and Cryptosporidium sp (3%). Although all samples were screened for Campylobacter and rotavirus, neither pathogen was detected. Water samples were taken from all the water sources in the study area and analysed microbiologically. Results showed that all the sources were contaminated with the faecal E. coli whose populations ranged from 14 CFU/1...
Background and Aims-We have previously reported a reduction in risk of diarrhoeal disease in chil... more Background and Aims-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, oVered an opportunity to examine the protection oVered by solar disinfection against cholera. Methods-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. Results-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 diVerence 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. Conclusions-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.
We report simulations of the thermal effect of strong equatorial sunshine on water samples contam... more We report simulations of the thermal effect of strong equatorial sunshine on water samples contaminated with high populations of fecal coliforms. Water samples, heavily contaminated with a wild-type strain of Escherichia coli (starting population = 20 x 10(5) CFU/ml), are heated to those temperatures recorded for 2-liter samples stored in transparent plastic bottles and exposed to full Kenyan sunshine (maximum water temperature, 55 degrees C). The samples are completely disinfected within 7 h, and no viable E. coli organisms are detected at either the end of the experiment or a further 12 h later, showing that no bacterial recovery has occurred. The feasibility of employing solar disinfection for highly turbid, fecally contaminated water is discussed.
We report the results of experiments designed to improve the efficacy of the solar disinfection o... more We report the results of experiments designed to improve the efficacy of the solar disinfection of drinking water, inactivation process. The effects of periodic agitation, covering the rear surface of the container with aluminium foil, container volume and turbidity on the solar inactivation kinetics of Escherichia coli (starting population = 10(6) CFU ml(-1)) were investigated. It was shown that agitation promoted the release of dissolved oxygen from water with subsequent decrease in the inactivation rates of E. coli. In contrast, covering the rear surface of the solar disinfection container with aluminium foil improved the inactivation efficiency of the system. The mean decay constant for bacterial populations in foil-backed bottles was found to be a factor of 1.85 (std. dev. = 0.43) higher than that of non-foil-backed bottles. Inactivation rates decrease as turbidity increases. However, total inactivation was achievable in 300 NTU samples within 8 h exposure to strong sunshine. Inactivation kinetics was not dependent on the volume of the water container for volumes in the range 500-1500 ml.
We report the results of experiments designed to improve the efficacy of the solar disinfection o... more We report the results of experiments designed to improve the efficacy of the solar disinfection of drinking water, inactivation process. The effects of periodic agitation, covering the rear surface of the container with aluminium foil, container volume and turbidity on the solar inactivation kinetics of Escherichia coli (starting population = 10(6) CFU ml(-1)) were investigated. It was shown that agitation promoted the release of dissolved oxygen from water with subsequent decrease in the inactivation rates of E. coli. In contrast, covering the rear surface of the solar disinfection container with aluminium foil improved the inactivation efficiency of the system. The mean decay constant for bacterial populations in foil-backed bottles was found to be a factor of 1.85 (std. dev. = 0.43) higher than that of non-foil-backed bottles. Inactivation rates decrease as turbidity increases. However, total inactivation was achievable in 300 NTU samples within 8 h exposure to strong sunshine. Inactivation kinetics was not dependent on the volume of the water container for volumes in the range 500-1500 ml.
Hand hygiene (HH) is the most significant factor for the improvment of practices and reduction of... more Hand hygiene (HH) is the most significant factor for the improvment of practices and reduction of microorganism transmission to patients, visitors, and health care workers, yet compliance rates remaining low. This study aims to improve the compliance of intensive care unit (ICU) staff in hand disinfection; either by washing or rubbing with alcohol-based solution. We analysised the HH compliance of ICU staff at Al-Istishari hospital in Jordan over a period of four months (December 2008-April 2009). A total of 24 study participants were observed to have a high ratio of HH compliance rate after removing gloves (76%). This prospective, interventional study employed an exploratory mixed qualitative-quantitative method. The study was conducted between December 2008 and April 2009 in the ICU at Al-Istishari Hospital, Amman, Jordan. The Hand Washing Questionnaire (HWQ) and 80 h of observations were used to measure and evaluate the compliance of HH practices among ICU employees. The effective compliance to HH practice was as low as 28% in January, rising to 32% in April; a total improvement of 4%. This was accompanied by a corresponding improvement in the rate of nosocomial infection (NI). The NI rate dropped by 5.6% over a short period; from 16.7% in January 2009 to 11.1% in March 2009.We identified an inverse relationship between HH compliance and NI rates. These findings suggest that the NI rate of ICUs can be reduced by relatively inexpensive strategies. We propose that a national HH program should be implemented in all healthcare sectors in Jordan.
Background and Aims-We have previously reported a reduction in risk of diarrhoeal disease in chil... more Background and Aims-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, oVered an opportunity to examine the protection oVered by solar disinfection against cholera. Methods-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.
349 Maasai children younger than 6 years old were randomised by alternate household to drink wate... more 349 Maasai children younger than 6 years old were randomised by alternate household to drink water either left in plastic bottles exposed to sunlight on the roof of the house or kept indoors (control). The trial was run in Maasai by Maasai community elders. Children drinking solar disinfected water had a significantly lower risk of severe diarrhoeal disease over 8705 two weekly follow up visits; two week period prevalence was 48.8% compared with 58.1% in controls, corresponding to an attributable fraction of 16.0%. While this reduction is modest, it was sustained over a year in free living children. It confirms solar disinfection as eVective in vivo as a free, low technology, point of consumption method of improving water quality. The continuing use of solar disinfection by the community underlines the value of community participation in research. (Arch Dis Child 1999;81:337-338)
We report simulations of the thermal effect of strong equatorial sunshine on water samples contam... more We report simulations of the thermal effect of strong equatorial sunshine on water samples contaminated with high populations of fecal coliforms. Water samples, heavily contaminated with a wild-type strain of Escherichia coli (starting population ؍ 20 ؋ 10 5 CFU/ml), are heated to those temperatures recorded for 2-liter samples stored in transparent plastic bottles and exposed to full Kenyan sunshine (maximum water temperature, 55؇C). The samples are completely disinfected within 7 h, and no viable E. coli organisms are detected at either the end of the experiment or a further 12 h later, showing that no bacterial recovery has occurred. The feasibility of employing solar disinfection for highly turbid, fecally contaminated water is discussed.
349 Maasai children younger than 6 years old were randomised by alternate household to drink wate... more 349 Maasai children younger than 6 years old were randomised by alternate household to drink water either left in plastic bottles exposed to sunlight on the roof of the house or kept indoors (control). The trial was run in Maasai by Maasai community elders. Children drinking solar disinfected water had a significantly lower risk of severe diarrhoeal disease over 8705 two weekly follow up visits; two week period prevalence was 48.8% compared with 58.1% in controls, corresponding to an attributable fraction of 16.0%. While this reduction is modest, it was sustained over a year in free living children. It confirms solar disinfection as eVective in vivo as a free, low technology, point of consumption method of improving water quality. The continuing use of solar disinfection by the community underlines the value of community participation in research. (Arch Dis Child 1999;81:337-338)
Background and Aims-We have previously reported a reduction in risk of diarrhoeal disease in chil... more Background and Aims-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, oVered an opportunity to examine the protection oVered by solar disinfection against cholera. Methods-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.
349 Maasai children younger than 6 years old were randomised by alternate household to drink wate... more 349 Maasai children younger than 6 years old were randomised by alternate household to drink water either left in plastic bottles exposed to sunlight on the roof of the house or kept indoors (control). The trial was run in Maasai by Maasai community elders. Children drinking solar disinfected water had a significantly lower risk of severe diarrhoeal disease over 8705 two weekly follow up visits; two week period prevalence was 48.8% compared with 58.1% in controls, corresponding to an attributable fraction of 16.0%. While this reduction is modest, it was sustained over a year in free living children. It confirms solar disinfection as eVective in vivo as a free, low technology, point of consumption method of improving water quality. The continuing use of solar disinfection by the community underlines the value of community participation in research. (Arch Dis Child 1999;81:337-338)
A series of experiments is reported to identify and characterize the inactivation process in oper... more A series of experiments is reported to identify and characterize the inactivation process in operation when drinking water, heavily contaminated with a Kenyan isolate of Escherichia coli, is stored in transparent plastic bottles that are then exposed to sunlight. The roles of optical and thermal inactivation mechanisms are studied in detail by simulating conditions of optical irradiance, water turbidity and temperature, which were recorded during a series of solar disinfection measurements carried out in the Kenyan Rift Valley. Optical inactivation effects are observed even in highly turbid water (200 ntu) and at low irradiances of only 10 mW cm −2. Thermal inactivation is found to be important only at water temperatures above 45°C, at which point strong synergy between optical and thermal inactivation processes is observed. The results confirm that, where strong sunshine is available, solar disinfection of drinking water is an effective, low cost method for improving water quality and may be of particular use to refugee camps in disaster areas. Strategies for improving bacterial inactivation are discussed.
Abstract Hand hygiene (HH) is the most significant factor for the improvment of practices and red... more Abstract Hand hygiene (HH) is the most significant factor for the improvment of practices and reduction of microorganism transmission to patients, visitors, and health care workers, yet compliance rates remaining low. This study aims to improve the compliance of intensive care unit (ICU) staff in hand disinfection; either by washing or rubbing with alcohol-based solution. We analysised the HH compliance of ICU staff at Al-Istishari hospital in Jordan over a period of four months (December 2008-April 2009). A total of 24 study participants were observed to have a high ratio of HH compliance rate after removing gloves (76%). This prospective, interventional study employed an exploratory mixed qualitative-quantitative method. The study was conducted between December 2008 and April 2009 in the ICU at Al-Istishari Hospital, Amman, Jordan. The Hand Washing Questionnaire (HWQ) and 80 h of observations were used to measure and evaluate the compliance of HH practices among ICU employees. The...
Stool samples were collected during August 1994 from seventy rural Maasai children under the age ... more Stool samples were collected during August 1994 from seventy rural Maasai children under the age of five years who were living in the Maasailand region of the Kenyan Rift Valley. Microbiological analysis was carried out on these samples to identify which intestinal pathogens were present among the infant population of the Maasai. Of the samples studied 54% were pathogen positive. The most common pathogen isolated was Giardia lamblia which was detected in 31% of the samples. Other pathogens that were detected include: Entamoeba histolytica (23%), Enteropathogenic Escherichia coli (13%), Strongyloides stercoralis (4%), Blastocystis hominis (3%) and Cryptosporidium sp (3%). Although all samples were screened for Campylobacter and rotavirus, neither pathogen was detected. Water samples were taken from all the water sources in the study area and analysed microbiologically. Results showed that all the sources were contaminated with the faecal E. coli whose populations ranged from 14 CFU/1...
Background and Aims-We have previously reported a reduction in risk of diarrhoeal disease in chil... more Background and Aims-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, oVered an opportunity to examine the protection oVered by solar disinfection against cholera. Methods-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. Results-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 diVerence 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. Conclusions-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.
We report simulations of the thermal effect of strong equatorial sunshine on water samples contam... more We report simulations of the thermal effect of strong equatorial sunshine on water samples contaminated with high populations of fecal coliforms. Water samples, heavily contaminated with a wild-type strain of Escherichia coli (starting population = 20 x 10(5) CFU/ml), are heated to those temperatures recorded for 2-liter samples stored in transparent plastic bottles and exposed to full Kenyan sunshine (maximum water temperature, 55 degrees C). The samples are completely disinfected within 7 h, and no viable E. coli organisms are detected at either the end of the experiment or a further 12 h later, showing that no bacterial recovery has occurred. The feasibility of employing solar disinfection for highly turbid, fecally contaminated water is discussed.
We report the results of experiments designed to improve the efficacy of the solar disinfection o... more We report the results of experiments designed to improve the efficacy of the solar disinfection of drinking water, inactivation process. The effects of periodic agitation, covering the rear surface of the container with aluminium foil, container volume and turbidity on the solar inactivation kinetics of Escherichia coli (starting population = 10(6) CFU ml(-1)) were investigated. It was shown that agitation promoted the release of dissolved oxygen from water with subsequent decrease in the inactivation rates of E. coli. In contrast, covering the rear surface of the solar disinfection container with aluminium foil improved the inactivation efficiency of the system. The mean decay constant for bacterial populations in foil-backed bottles was found to be a factor of 1.85 (std. dev. = 0.43) higher than that of non-foil-backed bottles. Inactivation rates decrease as turbidity increases. However, total inactivation was achievable in 300 NTU samples within 8 h exposure to strong sunshine. Inactivation kinetics was not dependent on the volume of the water container for volumes in the range 500-1500 ml.
We report the results of experiments designed to improve the efficacy of the solar disinfection o... more We report the results of experiments designed to improve the efficacy of the solar disinfection of drinking water, inactivation process. The effects of periodic agitation, covering the rear surface of the container with aluminium foil, container volume and turbidity on the solar inactivation kinetics of Escherichia coli (starting population = 10(6) CFU ml(-1)) were investigated. It was shown that agitation promoted the release of dissolved oxygen from water with subsequent decrease in the inactivation rates of E. coli. In contrast, covering the rear surface of the solar disinfection container with aluminium foil improved the inactivation efficiency of the system. The mean decay constant for bacterial populations in foil-backed bottles was found to be a factor of 1.85 (std. dev. = 0.43) higher than that of non-foil-backed bottles. Inactivation rates decrease as turbidity increases. However, total inactivation was achievable in 300 NTU samples within 8 h exposure to strong sunshine. Inactivation kinetics was not dependent on the volume of the water container for volumes in the range 500-1500 ml.
Hand hygiene (HH) is the most significant factor for the improvment of practices and reduction of... more Hand hygiene (HH) is the most significant factor for the improvment of practices and reduction of microorganism transmission to patients, visitors, and health care workers, yet compliance rates remaining low. This study aims to improve the compliance of intensive care unit (ICU) staff in hand disinfection; either by washing or rubbing with alcohol-based solution. We analysised the HH compliance of ICU staff at Al-Istishari hospital in Jordan over a period of four months (December 2008-April 2009). A total of 24 study participants were observed to have a high ratio of HH compliance rate after removing gloves (76%). This prospective, interventional study employed an exploratory mixed qualitative-quantitative method. The study was conducted between December 2008 and April 2009 in the ICU at Al-Istishari Hospital, Amman, Jordan. The Hand Washing Questionnaire (HWQ) and 80 h of observations were used to measure and evaluate the compliance of HH practices among ICU employees. The effective compliance to HH practice was as low as 28% in January, rising to 32% in April; a total improvement of 4%. This was accompanied by a corresponding improvement in the rate of nosocomial infection (NI). The NI rate dropped by 5.6% over a short period; from 16.7% in January 2009 to 11.1% in March 2009.We identified an inverse relationship between HH compliance and NI rates. These findings suggest that the NI rate of ICUs can be reduced by relatively inexpensive strategies. We propose that a national HH program should be implemented in all healthcare sectors in Jordan.
Background and Aims-We have previously reported a reduction in risk of diarrhoeal disease in chil... more Background and Aims-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, oVered an opportunity to examine the protection oVered by solar disinfection against cholera. Methods-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.
349 Maasai children younger than 6 years old were randomised by alternate household to drink wate... more 349 Maasai children younger than 6 years old were randomised by alternate household to drink water either left in plastic bottles exposed to sunlight on the roof of the house or kept indoors (control). The trial was run in Maasai by Maasai community elders. Children drinking solar disinfected water had a significantly lower risk of severe diarrhoeal disease over 8705 two weekly follow up visits; two week period prevalence was 48.8% compared with 58.1% in controls, corresponding to an attributable fraction of 16.0%. While this reduction is modest, it was sustained over a year in free living children. It confirms solar disinfection as eVective in vivo as a free, low technology, point of consumption method of improving water quality. The continuing use of solar disinfection by the community underlines the value of community participation in research. (Arch Dis Child 1999;81:337-338)
We report simulations of the thermal effect of strong equatorial sunshine on water samples contam... more We report simulations of the thermal effect of strong equatorial sunshine on water samples contaminated with high populations of fecal coliforms. Water samples, heavily contaminated with a wild-type strain of Escherichia coli (starting population ؍ 20 ؋ 10 5 CFU/ml), are heated to those temperatures recorded for 2-liter samples stored in transparent plastic bottles and exposed to full Kenyan sunshine (maximum water temperature, 55؇C). The samples are completely disinfected within 7 h, and no viable E. coli organisms are detected at either the end of the experiment or a further 12 h later, showing that no bacterial recovery has occurred. The feasibility of employing solar disinfection for highly turbid, fecally contaminated water is discussed.
349 Maasai children younger than 6 years old were randomised by alternate household to drink wate... more 349 Maasai children younger than 6 years old were randomised by alternate household to drink water either left in plastic bottles exposed to sunlight on the roof of the house or kept indoors (control). The trial was run in Maasai by Maasai community elders. Children drinking solar disinfected water had a significantly lower risk of severe diarrhoeal disease over 8705 two weekly follow up visits; two week period prevalence was 48.8% compared with 58.1% in controls, corresponding to an attributable fraction of 16.0%. While this reduction is modest, it was sustained over a year in free living children. It confirms solar disinfection as eVective in vivo as a free, low technology, point of consumption method of improving water quality. The continuing use of solar disinfection by the community underlines the value of community participation in research. (Arch Dis Child 1999;81:337-338)
Background and Aims-We have previously reported a reduction in risk of diarrhoeal disease in chil... more Background and Aims-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, oVered an opportunity to examine the protection oVered by solar disinfection against cholera. Methods-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.
349 Maasai children younger than 6 years old were randomised by alternate household to drink wate... more 349 Maasai children younger than 6 years old were randomised by alternate household to drink water either left in plastic bottles exposed to sunlight on the roof of the house or kept indoors (control). The trial was run in Maasai by Maasai community elders. Children drinking solar disinfected water had a significantly lower risk of severe diarrhoeal disease over 8705 two weekly follow up visits; two week period prevalence was 48.8% compared with 58.1% in controls, corresponding to an attributable fraction of 16.0%. While this reduction is modest, it was sustained over a year in free living children. It confirms solar disinfection as eVective in vivo as a free, low technology, point of consumption method of improving water quality. The continuing use of solar disinfection by the community underlines the value of community participation in research. (Arch Dis Child 1999;81:337-338)
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