Microbial quality of water in rural communities of Trinidad.

A cross-sectional study was conducted in four rural communities of northeastern Trinidad to determine the microbial quality of water supply to households and that quality's relationship to source and storage device. Of the 167 household water samples tested, total coliforms were detected in 132 of the samples (79.0%), fecal coliforms in 102 (61.1%), and E. coli in 111 (66.5%). There were significant differences among the towns in the proportion of the samples contaminated with coliforms (P < 0.001) and E. coli (P < 0.001). Of 253 strains of E. coli studied, 4 (1.6%) were mucoid, 9 (3.6%) were hemolytic, and 37 (14.6%) were nonsorbitol fermenters. Of 69 isolates of E. coli tested, 10 (14.5%) were verocytotoxigenic. Twenty-eight (14.0%) of 200 E. coli isolates tested belonged to enteropathogenic serogroups. Standpipe, the most common water source, was utilized by 57 (34.1%) of the 167 households. Treated water (pipeborne in homes, standpipes, or truckborne) was supplied to 119 households (71.3%), while 48 households (28.7%) used water from untreated sources (rain, river/stream, or well) as their primary water supply. The type of household storage device was associated with coliform contamination. Water stored in drums, barrels, or buckets was more likely to harbor fecal coliforms (74.2% of samples) than was water stored in tanks (53.3% of samples), even after controlling for water source (P = 0.04). Compared with water from other sources, water piped into homes was significantly less likely to be contaminated with total coliforms (56.9% versus 88.8%, P < 0.001) and fecal coliforms (41.2% versus 69.8%, P < 0.01), even when the type of storage device was taken into account. However, fecal contamination was not associated with whether the water came from a treated or untreated source. We concluded that the drinking water in rural communities in Trinidad was grossly unfit for human consumption, due both to contamination of various water sources and during household water storage.     

Increasing equity of access to point-of-use water treatment products through social marketing and entrepreneurship: a case study in western Kenya

Point-of-use water chlorination reduces diarrhoea risk by 25–85%. Social marketing has expanded access to inexpensive sodium hypochlorite for water treatment, at a cost of less than US$0.01 per day, in Kenya. To increase product access, women's groups in western Kenya were trained to educate neighbours and sell health products to generate income. We evaluated this programme's impact on equity of access to water treatment products in a cross-sectional survey. We surveyed 487 randomly selected households in eight communities served by the women's groups. Overall, 20% (range 5–39%) of households in eight communities purchased and used chlorine, as confirmed by residual chlorine observed in stored water. Multivariate models using illiteracy and the poorest socioeconomic status as a referent showed that persons with at least some primary education (OR 2.5, 95% CI 1.8, 3.5) or secondary education (OR 5.4, 95% CI 1.6, 17.5) and persons in the four wealthiest quintiles (OR 2.5, 95% CI 1.0, 6.0) were more likely to chlorinate stored water. While this implementation model was associated with good product penetration and use, barriers to access to inexpensive water treatment remained among the very poor and less educated.     

Water and hygiene interventions to reduce diarrhoea in rural Afghanistan: a randomized controlled study

A randomized controlled trial of four interventions was conducted using tubewells (n=2,486), liquid sodium hypochlorite (‘Clorin’) distributed with an improved water vessel (n=2,305), hygiene promotion (n=1,877), and a combination of the three (n=2,040) to create an evidence-base for water policy in Afghanistan. A fifth group served as a control (n=2,377). Interventions were randomized across 32 villages in Wardak province. Outcomes were measured through two household surveys separated by one year and twice-weekly household surveillance conducted over 16 months. The households receiving all three interventions showed reduction in diarrhoea compared with the control group, through both longitudinal surveillance data (IRR [95% CI]=0.61 [0.47–0.81]) and cross-sectional survey data (AOR [95% CI]=0.53 [0.30–0.93]). This reduction was significant when all household members were included, but did not reach significance when only children under five were considered. These results suggest multi-barrier methods are necessary where there are many opportunities for water contamination. Surveillance data suggested a greater impact of interventions on reducing diarrhoeal diseases than data from the surveys. Higher economic status as measured through household assets was associated with lower rates of diarrhoea and greater intervention uptake, excepting Clorin. Use of soap was also associated with lower prevalence of diarrhoea.     

Effect of a boil water notice on behaviour in the management of a water contamination incident

In late 1998, the water supply of 878 households was affected by possible sewage contamination. A notice was issued to advise residents of the need to boil their water. This provided an opportunity to assess to what extent the boil water notice led people to avoid activities that might put them at risk of waterborne infection. A postal questionnaire sent to 350 randomly selected households in the affected area asked about timing and mode of receipt of the notice, risk behaviour (boiling water, brushing teeth, washing dishes, drinks for pets, preparation of food), and subsequent changes in drinking water consumption habits. Eighty-one per cent of the households surveyed engaged in behaviour likely to increase the risk of waterborne infection. Comments were collected from consumers on how to improve the management of future water contamination incidents.     

Microbial groundwater quality and its health implications for a border-strip irrigated dairy farm catchment, South Island, New Zealand

Intensification of dairying on irrigated pastures has led to concern over the microbial quality of shallow groundwater used for drinking purposes. The effects of intensive dairying and border-strip irrigation on the leaching of E. coli and Campylobacter to shallow groundwater were assessed over a three-year period in the Waikakahi catchment, Canterbury, New Zealand. Well selection excluded other sources of contamination so that the effect of dairying with border-strip irrigation could be assessed. Groundwater samples (135) were collected, mostly during the irrigation season, with E. coli being detected in 75% of samples. Campylobacter was identified in 16 samples (12%). A risk assessment of drinking water with these levels of Campylobacter was undertaken. A probability distribution was fitted to the observed Campylobacter data and the @RISK modeling software was used, assuming a dose response relationship for Campylobacter and consumption of 1 L/day of water. The probability of infection on any given day in the study area was estimated at 0.50% to 0.76%, giving an estimated probability of infection during the irrigation season of 60% to 75%. An epidemiological assessment of the Canterbury region comparing areas encompassing dairy within major irrigation schemes (~55% border-strip irrigation) to two control groups was undertaken. Control group 1 (CG1) encompasses areas of dairying without major irrigation schemes, and a second larger control group (CG2) comprises the rest of the Canterbury region. Comparisons of the subject group to control groups indicated that there was a statistically significant increase in age-standardised rates of campylobacteriosis (CG1 Relative Risk (RR)=1.51 (95% CI = 1.31-1.75); CG2 RR = 1.51 (1.33–1.72)); cryptosporidiosis (CG1 RR = 2.08 (1.55–2.79); CG2 RR = 5.33 (4.12–6.90)); and salmonellosis (CG2 RR = 2.05 (1.55–2.71)).     

Child dysentery in the Limpopo Valley: a cohort study of water, sanitation and hygiene risk factors

The objective of this cohort study was to assess risk factors for child dysentery and watery diarrhoea. The study participants consisted of 254 children aged 12–24 months in rural South Africa and Zimbabwe in households where drinking water was collected from communal sources. The main outcome measure was the most severe diarrhoea episode: dysentery, watery diarrhoea or none. For dysentery, drinking water from sources other than standpipes had a relative risk ratio of 3.8 (95% CI 1.5–9.8). Poor source water quality, as indicated by Escherichia coli counts of 10 or more cfu 100 ml^-1, increased risk by 2.9 (1.5–5.7). There were no other significant risk factors for dysentery and none for watery diarrhoea. In this study, endemic dysentery is associated only with faecal contamination of source water. Sources other than standpipes, including improved groundwater, are of greater risk. Remediation of water quality by treatment at source or in the household will be required to achieve access to safe drinking water in accordance with the 7th Millennium Development Goal.     

A community waterborne outbreak of salmonellosis and the effectiveness of a boil water order.

OBJECTIVES: A 1993 large water-borne outbreak of Salmonella typhimurium infections in Gideon, Mo, a city of 1100 with an unchlorinated community water supply, was investigated to determine the source of contamination and the effectiveness of an order to boil water. METHODS: A survey of household members in Gideon and the surrounding township produced information on diarrheal illness, water consumption, and compliance with the boil water order. RESULTS: More than 650 persons were ill; 15 were hospitalized, and 7 died. Persons consuming city water were more likely to be ill (relative risk [RR] = 9.1, 95% confidence interval [CI] = 2.9, 28.4), and the attack rate increased with increased water consumption. S. typhimurium was recovered from samples taken from a city fire hydrant and a water storage tower. Persons in 31% (30/ 98) of city households had drunk unboiled water after being informed about the boil water order, including 14 individuals who subsequently became ill. Reasons for noncompliance included "not remembering" (44%) and "disbelieving" (25%) the order. CONCLUSIONS: Communities with deteriorating water systems risk widespread illness unless water supplies are properly operated and maintained. Effective education to improve compliance during boil water orders is needed.     

Bacterial quality of drinking water stored in containers by boat households in Hue City, Vietnam

Objectives  To examine the bacterial quality of drinking water stored in containers by boat households in the river basin of Hue City, and associated factors. Methods  Ready-to-drink water stored in containers on boats was collected from 766 households. Escherichia coli (E. coli), total coliforms, and Enterobacteriaceae in the water were examined by the rehydratable dry-film plating method. Socioeconomic characteristics, water source, handling practices, and proficiency of disease prevention of individual households were assessed. Results   E. coli, over ten counts of total coliforms, and over ten counts of Enterobacteriaceae were detected in 25.7, 44.5, and 51.5% of 1-ml samples of ready-to-drink water stored in containers on the boats. Bacterial contamination of the water stored in containers by boat households was significantly associated with use of river water as a source of drinking water, non-boiling before storing containers for drinking, and limited proficiency in disease prevention regardless of the influence of socioeconomic characteristics of the households (P < 0.01, P < 0.05, P < 0.01, respectively). Conclusions  Bacterial contamination of ready-to-drink water stored by boat households was indicated. The households’ proficiency in disease prevention buffered contamination. A comprehensive health promotion program with a wide range of contents is required for the communities of boat households.     

Prevalence of Cryptosporidium parvum in private drinking water cisterns in Bani-Kenanah district, northern Jordan

Due to water scarcity in Jordan, the water authority only pump the water once or twice a week to the population. Thus people in rural areas, including the Bani-Kenanah district, make the most of their water resources by storing rainwater in private reservoirs for use during periods of water shortage. These reservoirs include; underground cisterns and concrete or metal tanks. The water collected in these reservoirs is at risk of contamination. During the period March-July 2002, the three types of reservoirs from 368 households were surveyed for presence of Escherichia coli and Cryptosporidium parvum, indicators of contamination. The cistern was the most contaminated reservoir with 17% (95% CI: 13,22) for E. coli (significant, P<0.05), and 2% (95% CI: 1,4) for C. parvum. Only 1% (95% CI: 1,6) of the metal reservoirs had E. coli, while concrete reservoirs were free. No C. parvum oocysts were detected in either the concrete or metal reservoirs. Reservoirs opening at floor level and the bucket kept outside the reservoir were significant (P<0.05) enhancing risk factors for contamination with C. parvum.     

Is fecal contamination of drinking water after collection associated with household water handling and hygiene practices? A study of urban slum households in Hyderabad, India

Water-borne illness, primarily caused by fecal contamination of drinking water, is a major health burden in the state of Andhra Pradesh, India. Currently drinking water is treated at the reservoir level and supplied on alternate days, necessitating storage in households for up to 48 hrs. We hypothesized that fecal contamination occurs principally during storage due to poor water handling. In this study we tested for coliform bacteria in water samples collected at distribution points as household storage containers were filled, and then tested containers in the same households 24–36 hours after collection. We also conducted an observational survey to make an assessment of water handling and hygiene. Ninety-two percent (47/51) of samples tested at supply points were adequately chlorinated and bacterial contamination was found in two samples with no residual chlorine. Samples collected from household storage containers showed an increase in contamination in 18/50 houses (36%). Households with contaminated stored samples did not show significant differences in demographics, water handling, hygiene practices, or sanitation. Nevertheless, the dramatic increase in contamination after collection indicates that until an uninterrupted water supply is possible, the point at which the biggest health impact can be made is at the household level.     

Outbreak of acute gastroenteritis due to a washwater-contaminated water supply, Switzerland, 2008

An operating error in a sewage treatment plant led to severe drinking water contamination in a well-defined district of a suburban municipality of Zurich, Switzerland. Despite the alert issued to the local population on the same day advising people not to consume the contaminated water, cases of acute gastroenteric diseases were subsequently observed. Considerable faecal contamination was detected the day after the incident in water samples taken up to 500 m from the sewage plant. In a retrospective epidemiological study involving 240 persons living in the affected area, 126 cases of acute gastrointestinal illness were documented. The epidemic curve revealed a peak incidence two days after the event. Stool samples from 11 of 20 patients were positive for noroviruses or Campylobacter jejuni. Although these microorganisms were not detected in the contaminated water, the subsequently conducted case–control study among the surveyed population showed that consumption of contaminated drinking water was associated with gastrointestinal illness (odds ratio 29.1; 95% confidence interval: 9.8–86.4; p = 0.001). The study also revealed the very probable time period of infection. We present the dimension and chronology of this outbreak and discuss the reasons for its localised and temporary spread.     

Occurrence of norovirus and other enteric viruses in untreated groundwaters of Korea

A total of 39 water samples from 23 different groundwater wells in Korea were collected and analyzed in order to monitor the occurrence of norovirus (NoV) and other indicator microbes as the first part of a national survey of groundwater. More than 500 L of untreated groundwater were filtered through 1MDS filters. Following elution and concentration by organic flocculation, PCR and sequence analysis were employed to detect and identify NoV, enterovirus, rotavirus, hepatitis A virus and adenovirus (Adv). Somatic and F-specific phages, heterotrophic bacteria, total coliforms and Escherichia coli were also analyzed to infer possible fecal contamination. NoVs were detected in 18% of the 39 samples. Five out of seven NoV-positive samples (71%) were identified as GI while the other two (29%) were GII. Enteroviruses and Advs were detected in two and three samples, respectively. Rotavirus and hepatitis A virus were not detected. Total coliforms, E. coli and coliphages were detected in 49, 15 and 13% of the samples, respectively, but did not appear to be suitable indicators of enteric virus contamination in groundwater. These results suggest that additional treatment may be needed for a significant number of groundwaters prior to use as drinking water.     

Combining modeling and monitoring to study fecal contamination in a small rural catchment

The present study sought to identify Escherichia coli sources in a small catchment and to use the agro-hydrological model soil and water assessment tool (SWAT) to estimate their impact on river water quality. The innovative aspects of this research are to assess the hourly variations of fecal contamination and to take these variations into account in the model to provide a better evaluation of river quality. Thus, water samples were taken weekly at the river outlet (n = 4) and 24-h monitoring sessions were performed during low and high-flow periods (n = 74). E. coli variations were found to be primarily linked to rainfall and not to resuspension mechanisms. Subdaily fluctuations and deviations were ±0.33 log₁₀ cfu/100 mL and ±0.70 log₁₀ cfu/100 mL for dry (<3 mm/day) and wet (>3 mm/day) weather, respectively. After river flow calibration, all known pollution sources (septic systems, manure spreading, farm discharges) were introduced into SWAT. The model reproduced the fecal contamination in the river and the use of subdaily deviations allowed us to evaluate the simulation quality and compare grab samplings with simulated daily E. coli concentration, thus confirming that the performance of the model is better when additional information on hourly concentration variations is used.     

Diarrhoea prevention in Bolivia through point-of-use water treatment and safe storage: a promising new strategy

A novel water quality intervention that consists of point-of-use water disinfection, safe storage and community education was field tested in Bolivia. A total of 127 households in two periurban communities were randomized into intervention and control groups, surveyed and the intervention was distributed. Monthly water quality testing and weekly diarrhoea surveillance were conducted. Over a 5-month period, intervention households had 44% fewer diarrhoea episodes than control households (P = 0.002). Infants < 1 year old (P = 0.05) and children 5-14 years old (P = 0.01) in intervention households had significantly less diarrhoea than control children. Campylobacter was less commonly isolated from intervention than control patients (P = 0.02). Stored water in intervention households was less contaminated with Escherichia coli than stored water in control households (P < 0.0001). Intervention households exhibited less E. coli contamination of stored water and less diarrhoea than control households. This promising new strategy may have broad applicability for waterborne disease prevention.     

The microbiological quality of potable water on board ships docking in the UK and the Channel Islands: an association of Port Health Authorities and Health Protection Agency Study

Providing safe potable water onboard vessels presents particular challenges and contamination can occur directly from source waters as well as during loading, storage and distribution. Between May and October 2005, 950 potable water samples were collected from 342 ships docking at ports. Comparison with Guidelines found 9% of samples contained coliforms, Escherichia coli or enterococci and 2.8% had faecal indicators (E. coli or enterococci). Action levels of aerobic colony count (ACC) bacteria were detected in 20% (22°C) and 21.5% (37°C) of samples. ACC results from one-off sampling are not informative as this does not enable port health authorities to monitor ACC trends. They should be removed as a routine criterion for remedial action and vessels should adopt the WHO Water Safety Plan approach, whilst continuing to monitor water quality with public health-based indicators (e.g. chlorine residual, coliforms, E. coli and enterococci). Logistic regression analyses identified practices associated with water quality. Practices protective against coliforms, E. coli or enterococci in potable supplies were: good hose hygiene, processing water onboard, maintaining free chlorine residual at 0.2 mg/L. This emphasizes the importance of good hygiene during potable water loading and maintaining adequate disinfection of supplies onboard.     

Geographical variation in antibiotic-resistant Escherichia coli isolates from stool, cow-dung and drinking water

Little information is available on relationships between the biophysical environment and antibiotic resistance. This study was conducted to investigate the antibiotic resistance pattern of Escherichia coli isolated from child stool samples, cow-dung and drinking water from the non-coastal (230 households) and coastal (187 households) regions of Odisha, India. Susceptibility testing of E. coli isolates (n = 696) to the following antibiotics: tetracycline, ampicillin/sulbactam, cefuroxime, cefotaxime, cefixime, cotrimoxazole, amikacin, ciprofloxacin, norfloxacin and nalidixic acid was performed by the disk diffusion method. Ciprofloxacin minimum inhibitory concentration (MIC) values were determined for ciprofloxacin-resistant isolates (n = 83). Resistance to at least one antibiotic was detected in 90% or more of the E. coli isolates. Ciprofloxacin MIC values ranged from 8 to 32 μg/mL. The odds ratio (OR) of resistance in E. coli isolates from children's stool (OR = 3.1, 95% CI 1.18-8.01), cow-dung (OR = 3.6, 95% CI 1.59-8.03, P = 0.002) and drinking water (OR = 3.8, 95% CI 1.00-14.44, P = 0.049) were higher in non-coastal compared to coastal region. Similarly, the co-resistance in cow-dung (OR = 2.5, 95% CI 1.39-4.37, P = 0.002) and drinking water (OR = 3.2, 95% CI 1.36-7.41, P = 0.008) as well as the multi-resistance in cow-dung (OR = 2.2, 95% CI 1.12-4.34, P = 0.022) and drinking water (OR = 2.7, 95% CI 1.06-7.07, P = 0.036) were also higher in the non-coastal compared to the coastal region.     

Faecal contamination of drinking water in a Brazilian shanty town: importance of household storage and new human faecal marker testing

Worldwide, contaminated drinking water poses a major health threat, particularly to child development. Diarrhoea represents a large part of the water-related disease burden and enteric infections have been linked to nutritional and growth shortfalls as well as long-term physical and cognitive impairment in children. Previous studies detailed the frequency of infection and the consequences for child health in a shanty town in north-east Brazil. To determine the frequency of contaminated water, we measured faecal contamination in primary drinking water samples from 231 randomly selected households. Risk for contamination was compared across source and storage types. Nearly a third of the study households (70/231: 30.3%) had contaminated drinking water; the source with the highest frequency of contamination was well water (23/24: 95.8%). For tap water, the type of storage had a significant effect on the susceptibility to contamination (c²=12.090; p=0.007). The observed pattern of contamination demonstrated the relative potential contributions of both source and storage. With evidence that supports the inclusion of source and storage in water quality surveys, this study, like others, suggests that contaminated drinking water in storage vessels may be an important factor for the documented diarrhoea disease burden in the Brazilian shanty town.     

The role of drinking water in the transmission of antimicrobial-resistant E. coli

To determine whether drinking water contaminated with antimicrobial-resistant E. coli is associated with the carriage of resistant E. coli, selected households sending water samples to Ontario and Alberta laboratories in 2005-2006 were asked to participate in a cross-sectional study. Household members aged ≥12 years were asked to complete a questionnaire and to submit a rectal swab. In 878 individuals, 41% carried a resistant strain of E. coli and 28% carried a multidrug-resistant strain. The risk of carriage of resistant E. coli was 1·26 times higher for users of water contaminated with resistant E. coli. Other risk factors included international travel [prevalence ratio (PR) 1·33], having a child in nappies (PR 1·33), being male (PR 1·33), and frequent handling of raw red meats (PR 1·10). Protecting private water sources (e.g. by improving systems to test and treat them) may help slow the emergence of antimicrobial resistance in E. coli.