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Biomedical subjects

M Elmore-Meegan

Publications and source records attributed to M Elmore-Meegan.

7 recordsLinked to original sources

Solar disinfection of drinking water contained in transparent plastic bottles: characterizing the bacterial inactivation process.

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 degrees 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.

Colony Count, Microbial↗

Inactivation of fecal bacteria in drinking water by solar heating.

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.

Desert Climate↗

Prevalence of enteropathogens in stools of rural Maasai children under five years of age in the Maasailand region of the Kenyan Rift Valley.

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/100 ml to greater than 1800 CFU/100ml.

Age Distribution↗

Comparing liquid crystal thermometer readings and mercury thermometer readings of infants and children in a traditional African setting. Implications for community-based health.

Liquid crystal thermometer (LCT) readings of skin temperatures were compared with mercury thermometer (MT) rectal temperature readings to assess the reliability of LCTs. Temperatures of 498 children were measured at two points in time. LCT skin temperature readings of children 0 to 52 months were on average 0.50 degrees C and 1.97 degrees C lower than MT rectal temperature readings. A strong correlation between temperature differences and LCT readings indicated that the greatest differences occurred at the lower LCT readings. These conclusions indicate LCT skin readings undermeasure temperature. Some of these differences were due to MTs not measuring temperatures below 35 degrees C. Children under 1 year of age had significantly greater differences than any other age group. Their LCT readings were, on average, 1.65 degrees C lower than their MT readings. Using MTs as a standard, LCTs were 100% sensitive and 92% specific for detecting children with hypothermia. LCTs were 38.5% sensitive and 100% specific for detecting fevers. These results suggest that LCTs leave undetected a large proportion of children who have fevers. However, they are sensitive for identifying children with hypothermia. A knowledge, attitude and practice (KAP) study indicated that local mothers can be identified who understand principles and procedures of LCTs, and accept them for health care of their child.

Age Factors↗

Maasai diet.

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Diet Surveys↗

Solar disinfection of drinking water and diarrhoea in Maasai children: a controlled field trial.

BACKGROUND: Solar radiation reduces the bacterial content of water, and may therefore offer a method for disinfection of drinking water that requires few resources and no expertise. METHODS: We distributed plastic water bottles to 206 Maasai children aged 5-16 years whose drinking water was contaminated with faecal coliform bacteria. Children were instructed to fill the bottle with water and leave it in full sunlight on the roof of the hut (solar group), or to keep their filled bottles indoors in the shade (control group). A Maasai-speaking fieldworker who lived in the community interviewed the mother of each child once every 2 weeks for 12 weeks. Occurrence and severity of diarrhoea was recorded at each follow-up visit. FINDINGS: Among the 108 children in households allocated solar treatment, diarrhoea was reported in 439 of the 2-week reporting periods during the 12-week trial (average 4.1 [SD 1.2] per child). By comparison, the 98 children in the control households reported diarrhoea during 444 2-week reporting periods (average 4.5 [1.2] per child). Diarrhoea severe enough to prevent performance of duties occurred during 186 reporting periods in the solar group and during 222 periods in the control group (average 1.7 [1.2] vs 2.3 [1.4]). After adjustment for age, solar treatment of drinking water was associated with a reduction in all diarrhoea episodes (odds ratio 0.66 [0.50-0.87]) and in episodes of severe diarrhoea (0.65 [0.50-0.86]). INTERPRETATION: Our findings suggest that solar disinfection of water may significantly reduce morbidity in communities with no other means of disinfection of drinking water, because of lack of resources or in the event of a disaster.

Adolescent↗