Laboratory assessment of a gravity-fed ultrafiltration water treatment device designed for household use in low-income settings. The American journal of tropical medicine and hygiene, 80 (5 Abstract. Interventions to improve water quality, particularly when deployed at the household level, are an effective means of preventing endemic diarrheal disease, a leading cause of mortality and morbidity in the developing world. We assessed the microbiologic performance of a novel water treatment device designed for household use in low-income settings. The device employs a backwashable hollow fiber ultrafiltration cartridge and is designed to mechanically remove enteric pathogenic bacteria, viruses, and protozoan cysts from drinking water without water pressure or electric power. In laboratory testing through 20,000 L (~110% of design life) at moderate turbidity (15 nephelometric turbidity unit [NTU] ), the device achieved log 10 reduction values of 6.9 for Escherichia coli , 4.7 for MS2 coliphage (proxy for enteric pathogenic viruses), and 3.6 for Cryptosporidium oocysts, thus exceeding levels established for microbiological water purifiers. With periodic cleaning and backwashing, the device produced treated water at an average rate of 143 mL/min (8.6 L/hour) (range 293 to 80 mL/min) over the course of the evaluation. If these results are validated in field trials, the deployment of the unit on a wide scale among vulnerable populations may make an important contribution to public health efforts to control intractable waterborne diseases.

Human enteropathogenic microsporidia (HEM), Cryptosporidium parvum, Cyclospora cayetanesis, and Giardia lamblia are associated with gastrointestinal disease in humans. To date, the mode of transmission and environmental occurrence of HEM (Encephalitozoon intestinalis and Enterocytozoon bieneusi) and Cyclospora cayetanesis have not been fully elucidated due to lack of sensitive and specific environmental screening methods. The present study was undertaken with recently developed methods, to screen various water sources used for public consumption in rural areas around the city of Guatemala. Water concentrates collected in these areas were subjected to community DNA extraction followed by PCR amplification, PCR sequencing and computer database homology comparison (CDHC). All water samples screened in this study had been previously confirmed positive for Giardia spp. by immunofluorescent assay (IFA). Of the 12 water concentrates screened, 6 showed amplification of microsporidial SSU-rDNA and were subsequently confirmed to be Encephalitozoon intestinalis. Five of the samples allowed for amplification of Cyclospora 18S-rDNA; three of these were confirmed to be Cyclospora cayetanesis while two could not be identified because of inadequate sequence information. Thus, this study represents the first confirmed identification of Cyclospora cayetanesis and Encephalitozoon intestinalis in source water used for consumption. The fact that the waters tested may be used for human consumption indicates that these emerging protozoa may be transmitted by ingestion of contaminated water.

Consumption of water from vending machines has recently increased in the United States. However, studies describing the bacteriological quality of water from these machines are scarce. In this study, bacteriological analyses were performed on samples from 30 water vending machines (W VM s), three of which were sampled weekly for 3 weeks. Bacteriological analyses were also conducted on the nozzle dispensers and the drains of 15 WVMs. Heterotrophic bacteria, total and fecal coliforms, and Pseudomonas aeruginosa were enumerated. Physico-chemical parameters such as pH, temperature, turbidity and residual chlorine were also examined. P. aeruginosa was found in 23% of the water samples and coliform bacteria in 20%. Heterotrophic plate count (HPC) bacteria were found in all samples and 73% had numbers greater than 500 colony forming units (CFU) ml ±1 . The HPC bacteria ranged from 9 to 48 000 CFU per sampled area on the dispensing nozzle. Total coliforms and Escherichia coli were detected in the drain samples with HPC bacterial concentrations from 1000 to 56 000 CFU per sampled area. No significant correlations were found between the physico-chemical and bacteriological parameters.

These units comply with the criteria guidelines for microbial removal under the United States Environmental Protection Agency's "Guide Standard and Protocol for Testing Microbiological Water Purifiers."

The MK filter is an electropositively charged filter that can be used to concentrate enteroviruses from large volumes (400 to 1,000 liters) of water. This filter is less expensive than the commonly used lMDS electropositive filter. In this study, we compared the recovery of poliovirus 1 (PVI) and that of coxsackievirus B3 (CB3) from 378 liters of tap water, using both the MK and the lMDS filters. Viruses were eluted from the filters with 3% beef extract buffered with 0.05 M glycine (pH 9.5) and reconcentrated via organic flocculation. At high virus inputs (approximately 106 PFU), the overall recovery (after elution and reconcentration) of PV1 and CB3 from tap water with the MK filter was less than that achieved with the IMDS filter (P < 0.05). The recoveries of PV1 from tap water with the MK and IMDS filters were 73.2% ± 26% (n = 5 trials) and 90.2% ± 5.9% (n = 5 trials), respectively. The recoveries of CB3 from tap water with the MK and lMDS filters were 32.8% ± 34.5% (n = 4 trials) and 95.8% + 12.0%o (n = 4 trials), respectively. This study indicated that the MK filter consistently provided lower recovery, with wider variability, of PV1 and CB3 from tap water than the lMDS filter.