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Primers and a TaqMan probe for the 5' -untranslated region (UTR) of the hepatitis A virus (HAV) genome were designed and evaluated. The assay detected 0.5 infectious units of HAV and 40 copies of a synthetic transcript and provided an important screening tool for rapid quantitative HAV detection in clinical or environmental samples.

Bacterial pathogens such as Escherichia coli, Salmonella-, Shigella- and Vibrio species are known to be common causative agents for diarrhoeal disease in humans. This study aimed to develop a culture-independent PCR assay for the detection of bacterial pathogens present in human faecal samples collected using a less intrusive faecal collection technique, the Bio-wipe kit. A multiplex-PCR (m-PCR) was optimised targeting the E. coli mdh gene, the Salmonella IpaB gene, the Vibrio sodB gene, and the Ial and IpaH genes present in entero-invasive E. coli and Shigella spp. The influence of the DNA extraction method, and sensitivity and specificity of the m-PCR and the Bio-wipe storage conditions on the detection of the bacterial pathogens was investigated. A guanidium thiocyanate DNA extraction method used with laboratory-prepared spin columns could successfully extract DNA from 93% of the samples analysed. The m-PCR could successfully identify and differentiate between the various pathogens tested and was specific for the selected pathogens. Faecal matter was successfully recovered from used Bio-wipes and the bacterial DNA could be detected from these samples at concentrations of 10 cfu. Bacterial DNA could be recovered from the Bio-wipes 5 to 10 d after use when the Bio-wipes were stored at 30°C and 14 d after usage when stored at ambient temperature. Thus the Bio-wipe kit, along with the m-PCR, can be used for collection and detection of bacterial pathogens during outbreaks and in rural settings. [ABSTRACT FROM AUTHOR]

The effectiveness of point-of-use water treatment may be limited by declining use over time, particularly when water treatment is introduced via targeted intervention programmes. In order to evaluate the long-term uptake and use of locally produced ceramic water filters in rural Cambodia, we visited households that had received filters as part of NGO-subsidized distribution programmes over a 4 year period from 2002 to 2006. Of the more than 2,000 filters distributed, we visited 506 randomly selected households in 13 villages spanning three provinces to assess filter time in use and to collect data on factors potentially correlated with long-term use. Results indicate that filter use declined at the rate of approximately 2% per month after implementation, largely owing to breakages, and that, controlling for time since implementation, continued filter use over time was most closely positively associated with: related water, sanitation and hygiene practices in the home; cash investment in the technology by the household; and use of surface water as a primary drinking water source. [ABSTRACT FROM AUTHOR]

Ceramic materials that can adsorb and/or inactivate viruses in water may find widespread application in low-tech drinking-water treatment technologies in developing countries, where porous ceramic filters and ceramic granular media filters are increasingly promoted for that purpose. We examined the adsorption and subsequent inactivation of bacteriophages MS2 and ϕX-174 on five ceramic media in batch adsorption studies to determine media suitability for use in a ceramic water filter application. The media examined were a kaolinitic ceramic medium and four kaolinitic ceramic media amended with iron or aluminium oxides that had been incorporated into the kaolinitic clays before firing. Batch adsorption tests indicate increased sorption and inactivation of surrogate viruses by media amended with Fe and Al oxide, with FeOOH-amended ceramic inactivating all bacteriophages up to 8 log10. Unmodified ceramic was a poor adsorbent of bacteriophages at less than 1 log10 adsorption-inactivation and high recovery of sorbed phages. These studies suggest that contact with ceramic media, modified with electropositive Fe or Al oxides, can reduce bacteriophages in waters to a greater extent than unmodified ceramic. [ABSTRACT FROM AUTHOR]

Escherichia coli counts in household drinking water may or may not reliably indicate the presence of diarrheogenic pathogens originating in feces. The extent to which a bacterial indicator like E. coli predicts risks from all classes of pathogens (viruses and parasites as well as bacteria), especially in tropical waters, is uncertain. To investigate the association between E. coli in household drinking water and diarrheal diseases in Cambodia, we conducted a 22 week cohort study in a rural village in Kandal Province. Episodes of diarrhea (all) and bloody diarrhea (dysentery), water quality, water sources, and other covariates were monitored biweekly in 180 households. Households used a variety of water treatment, storage, and handling practices. Results suggest a weak but positive association between E. coli counts in household drinking water and diarrhea and for diarrhea with blood (dysentery), after adjusting for clustering within households and within individuals over time. Compared to households with <1 E. coli/100 ml in drinking water, there was no observed increased risk for having 1-10 E. coli/100ml (LPR = 0.98, 95% CI 0.81-1.2 for diarrheal disease; LPR = 0.75, 95% CI 0.36-1.6 for dysentery). Households with measured E. coli of 11-100/100 ml did report increased diarrhea (LPR = 1.2, 95% CI 1.1-1.3 for diarrheal disease; LPR = 1.4, 95% CI 1.0-1.8 for dysentery), as did those with 101-1,000 E. coli/100 ml (LPR = 1.2, 95% CI 1.2-1.3 for diarrheal disease; LPR = 1.2, 95% CI 1.0-1.4 for dysentery) and those with >1,000 E. coli per 100ml sample (LPR = 1.2, 95% CI 1.1-1.2 for diarrheal disease; LPR = 1.2, 95% CI 1.0-1.3 for dysentery). Unlike the results of some previous studies, diarrheal disease risks did not increase progressively in magnitude with increasing concentration of E. coli in drinking water. [ABSTRACT FROM AUTHOR]

The use of antibiotics for growth promotion and disease treatment by the commercial swine industry has led to high proportions of multiple antibiotic-resistant enteric bacteria being shed by these animals and concerns about the environmental spread of these bacteria. A study was conducted to quantify the extent of release of antibiotic-resistant E. coli from swine farms into groundwater. Four study sites, two swine farms and two reference sites (crop farms), with known groundwater flow paths were screened for E. coli four times over the course of one and a half years. A total of 100 biochemically-confirmed E. coli were collected from the four sites. There were statistically significantly higher E. coli levels at the two swine farm sites than at the reference sites. The bacterial isolates were tested for antibiotic resistance using a panel of 17 drugs that are typical of human and veterinary use. There were 19 and 71 E. coli isolates from swine farms #1 and #2, respectively, with most (68%) being resistant to 1–6 antimicrobials. Only one E. coli isolate from each of the reference sites showed antimicrobial resistance traits. The results of this study demonstrate that antibiotic-resistant E. coli strains are present in groundwaters of swine farms with a typical lagoon and land application system for waste management. [ABSTRACT FROM AUTHOR]

More than a billion people in the developing world lack access to safe and reliable sources of drinking water. Point of use (POU) household water treatment technology allows people to improve the quality of their water by treating it in the home. One emerging POU technology is the biosand filter (BSF), a household-scale, intermittently operated slow sand filter. Laboratory and field studies examined Escherichia coli reductions achieved by the BSF. During two laboratory studies, mean E. coli reductions were 94% and they improved over the period of filter use, reaching a maximum of 99%. Field analysis conducted on 55 household filters near Bonao, Dominican Republic averaged E. coli reductions of 93%. E. coli reductions by the BSF in laboratory and field studies were less than those typically observed for traditional slow sand filters (SSFs), although as for SSFs microbial reductions improved over the period of filter use. Further study is needed to determine the factors contributing to microbial reductions in BSFs and why reductions are lower than those of conventional SSFs. [ABSTRACT FROM AUTHOR]

New and improved methods have been developed to detect somatic and male-specific coliphages in large volumes of water by single agar layer (SAL), enrichment and membrane filter methods. Somatic coliphages were detected efficiently on E. coli hosts C and CN13, male-specific coliphages were detected more efficiently on E. coli Famp than on Salmonella typhimurium WG49 and both types of coliphages were detected simultaneously on E. coli C3000. For water volumes of up to 100 ml, the SAL method was efficient and reliable. For water volumes of <1 L and as many as 10 multiple 1 L volumes, the enrichment method was efficient in detecting very low numbers of coliphages. Membrane filter methods, in which coliphages were adsorbed to and eluted from filters, also were relatively efficient, but they were less efficient than SAL and enrichment methods and were considered to be more cumbersome. For filter adsorption-elution methods, coliphage recoveries were most efficient for cellulose ester filters, less efficient for electropositive 1MDS filters and least efficient for a direct membrane filter method. Overall, the enrichment method was preferred because of its ability to easily and rapidly detect low levels of coliphages in large sample volumes by either presence--absence or most probable number quantification. [ABSTRACT FROM AUTHOR]

Oxidant solutions of mostly free chlorine can be electrochemically produced on-site from brine (NaCl) solution and used to disinfect water at the household or community level. In this study electrochemical oxidant (ECO) from brine and free chlorine were evaluated under laboratory conditions for inactivation of test microbes. Purified suspensions of Escherichia coli, the rugose strain of Vibrio cholerae, Clostridium perfringens spores, MS2 coliphage and Cryptosporidium parvum oocysts were treated with 2 mg/L or 5 mg/L solutions of ECO or free chlorine at 5°C and 25°C and pH 6, 8, and 10 (pH 7 and 25°C only for C. parvum oocysts) for contact times <60 min. Under nearly all conditions, inactivation kinetics were more rapid for E. coli, V. cholerae, C. perfringens spores and MS2 coliphage with ECO than with free chlorine. ECO reduced E. coli, V. cholerae and MS2 by >4 log10 within 30 min and C. perfringens spores by >2 log10 within 10 min at pH 8 and 25°C. Contrary to previous results, however, C. parvum oocysts were not inactivated by ECO, and the reasons for this difference are uncertain. The on-site electrolytic generation of oxidants from brine provided a convenient and inexpensive disinfectant containing free chlorine that was effective against many enteric microbes, for the treatment of household and community drinking-water supplies worldwide. However, the effectiveness of such oxidants for inactivating C. parvum oocysts was variable and sometimes ineffective. [ABSTRACT FROM AUTHOR]

Millions of people, most of whom are children in developing countries, die of basic hygiene-related diseases every year. Interventions in hygiene, sanitation and water supply have been shown to control disease burden. Universal access to improved water sources and basic sanitation remains elusive but is an important long-term goal. Studies have shown that improving the microbiological quality of household water by on-site or point-of-use treatment and safe storage in improved vessels reduces diarrhocal and other waterborne diseases in communities and households of developing and developed countries. The extent to which improving drinking water quality at the household level reduces diarrhoeal disease probably depends on a variety of technology-related and site-specific environmental and demographic factors that require further investigation, characterisation and analyses. [ABSTRACT FROM AUTHOR]

On-site septic tank-soil absorption systems treating domestic wastewater have contaminated groundwaters with enteric viruses and other pathogens and caused drinking waterborne outbreaks. The factors influencing pathogen transport, survival and fate at on-site wastewater treatment systems remain inadequately characterised. We studied the survival and transport of a model enterovirus (BE-1) and faecal coliform bacteria in four on-site wastewater treatment systems (three conventional and one low pressure, small pipe diameter, pumped system) located in sandy soils typical of the coastal plains. Septic system wastewaters were seeded seasonally with known amounts of BE-1 and the fate of BE-1, faecal coliforms and other wastewater constituents were followed for three months in seeded wastewaters and groundwaters of drainfield monitoring wells. BE-1 levels in seeded wastewaters declined exponentially by kinetics consistent with a 3d hydraulic residence time. BE-1 was detected in ground waters of monitoring wells as early as ld after seeding and persisted up to two months. Virus detection in ground water was greater in winter than in summer and was positively associated with proximity to septic effluent distribution lines, drainfield soils with the lowest clay content, elevated ground water pH and shallower vadose zones. Viruses were not strongly associated with either distance from septic tank or faecal coliform levels in groundwater. Under optimum conditions, virus reductions were as high as 9 log10, but in systems with the most coarse (sand) soils and highest water tables (most shallow vadose zones), there was extensive ground water contamination by viruses and other wastewater constituents. Under some conditions, septic systems in sandy coastal plains soils can contaminate ground water with viruses and other wastewater constituents. [ABSTRACT FROM AUTHOR]

Presents a study to evaluate the survival of Escherichia coli, Salmonella typhi, Shigella sonnei, poliovirus type 1 and a parvovirus in seawater. Comparison of the parvovirus and the poliovirus; Findings that microbial survival in seawater was greater under laboratory conditions than under in-situ conditions; How the lower survival of E. coli compared to the bacterial and viral pathogens under laboratory conditions raises concerns because it is a key microbial indicator of faecal contamination.

Discusses how cryptosporidium parvum oocysts in water were exposed to distinct wavelength bands of collimated beam ultraviolet (UV) radiation. Consideration of radiation across the germicidal UV wavelength range; Use of potassium ferrioxalate actinometry; Characteristics of a oocyst infectivity with the use of a cell culture assay.

A procedure to monitor virus removal at an advanced water treatment (AWT) system for water repurification was developed. The procedure isbased on enumerating indigenous coliphages native to waste water throughout the AWT system. Two different methods were evaluated for enumerating the indigenous coliphage, the Membrane Filtration Method (MFM) and the Double Agar Layer (DAL) method. For the DAL method, C3000 host organism was used while for the MFM, tests were done using both the C3000 and the Famp host organisms. Significant natural coliphages were observed in the secondary effluent which allowed monitoring overall AWT removal in the range of 4--6 logs. Enumerating indigenous coliphages was shown to be a viable and sensitive method for monitoring the performance of the AWT system in removing viruses. In addition, the MFM was shown to be an effective presence/absence test for virusesin the AWT effluent, offering results on the same day on which the sample is taken. [ABSTRACT FROM AUTHOR]

A breakthrough procedure to monitor the overall treatment reliability of an advanced water treatment (AWT) system for water repurification was developed. The procedure is based on enumerating indigenous coliphages native to the wastewater throughout the AWT system. Two different methods were evaluated for enumerating the indigenous coliphage,which are: the Membrane Filtration Method (MFM) and the Double Agar Layer (DAL) method. For the DAL method, C3000 host organism was only used while for the MFM, tests were done using either C3000 or Famp host organisms. Significant amount of natural coliphage was observed inthe secondary effluent which allowed monitoring an overall AWT removal in the range of 4 - 6 logs. The MFM was shown to be a viable and sensitive enumerating method to monitor the treatment reliability of the AWT system. In addition, the MFM was shown to be an effective presence/absence test for viruses in the AWT effluent, with incubation time as low as 8 hours. [ABSTRACT FROM AUTHOR]