Jeanine D. Plummer

Torque teno virus: an improved indicator for viral pathogens in drinking waters

BackgroundCurrently applied indicator organism systems, such as coliforms, are not fully protective of public health from enteric viruses in water sources. Waterborne disease outbreaks have occurred in systems that tested negative for coliforms, and positive coliform results do not necessarily correlate with viral risk. It is widely recognized that bacterial indicators do not co-occur exclusively with infectious viruses, nor do they respond in the same manner to environmental or engineered stressors. Thus, a more appropriate indicator of health risks from infectious enteric viruses is needed.Presentation of the hypothesisTorque teno virus is a small, non-enveloped DNA virus that likely exhibits similar transport characteristics to pathogenic enteric viruses. Torque teno virus is unique among enteric viral pathogens in that it appears to be ubiquitous in humans, elicits seemingly innocuous infections, and does not exhibit seasonal fluctuations or epidemic spikes. Torque teno virus is transmitted primarily via the fecal-oral route and can be assayed using rapid molecular techniques. We hypothesize that Torque teno virus is a more appropriate indicator of viral pathogens in drinking waters than currently used indicator systems based solely on bacteria.Testing the hypothesisTo test the hypothesis, a multi-phased research approach is needed. First, a reliable Torque teno virus assay must be developed. A rapid, sensitive, and specific PCR method using established nested primer sets would be most appropriate for routine monitoring of waters. Because PCR detects both infectious and inactivated virus, an in vitro method to assess infectivity also is needed. The density and occurrence of Torque teno virus in feces, wastewater, and source waters must be established to define spatial and temporal stability of this potential indicator. Finally, Torque teno virus behavior through drinking water treatment plants must be determined with co-assessment of traditional indicators and enteric viral pathogens to assess whether correlations exist.Implications of the hypothesisIf substantiated, Torque teno virus could provide a completely new, reliable, and efficient indicator system for viral pathogen risk. This indicator would have broad application to drinking water utilities, watershed managers, and protection agencies and would provide a better means to assess viral risk and protect public health.

Effective control of Schistosoma haematobium infection in a Ghanaian community following installation of a water recreation area.

Background Urogenital schistosomiasis caused by Schistosoma haematobium was endemic in Adasawase, Ghana in 2007. Transmission was reported to be primarily through recreational water contact. Methods We designed a water recreation area (WRA) to prevent transmission to school-aged children. The WRA features a concrete pool supplied by a borehole well and a gravity-driven rainwater collection system; it is 30 m2 and is split into shallow and deep sections to accommodate a variety of age groups. The WRA opened in 2009 and children were encouraged to use it for recreation as opposed to the local river. We screened children annually for S. haematobium eggs in their urine in 2008, 2009, and 2010 and established differences in infection rates before (2008–09) and after (2009–10) installation of the WRA. After each annual screening, children were treated with praziquantel and rescreened to confirm parasite clearance. Principal Findings Initial baseline testing in 2008 established that 105 of 247 (42.5%) children were egg-positive. In 2009, with drug treatment alone, the pre-WRA annual cumulative incidence of infection was 29 of 216 (13.4%). In 2010, this incidence rate fell significantly (p<0.001, chi-squared) to 9 of 245 (3.7%) children after installation of the WRA. Logistic regression analysis was used to determine correlates of infection among the variables age, sex, distance between home and river, minutes observed at the river, low height-for-age, low weight-for-age, low Body Mass Index (BMI)-for-age, and previous infection status. Conclusion/Significance The installation and use of a WRA is a feasible and highly effective means to reduce the incidence of schistosomiasis in school-aged children in a rural Ghanaian community. In conjunction with drug treatment and education, such an intervention can represent a significant step towards the control of schistosomiasis. The WRA should be tested in other water-rich endemic areas to determine whether infection prevalence can be substantially reduced.

Diagnostic accuracy of urine filtration and dipstick tests for Schistosoma haematobium infection in a lightly infected population of Ghanaian schoolchildren

Two screening methods, reagent dipsticks for hematuria and urine filtration for Schistosoma haematobium eggs, were evaluated for their sensitivity and specificity in diagnosing infection with S. haematobium in lightly infected Ghanaian children. Schoolchildren aged 8-18 years (n=255) provided urine samples on three occasions. Overall, 36.4% of girls and 50.7% of boys presented with eggs at least once; 3.3% of girls and 7.5% of boys presented with both eggs and hematuria three times. Many children presented with eggs but without hematuria, or with hematuria but without eggs. When each child was screened three times, the sensitivity of each test method improved by at least 22.9% as compared with single screening, but previously unidentified infections were detected at the third screening, indicating that even three screenings is insufficient. Nearly half of lightly infected children (<50 eggs/10 ml urine, by maximum egg count) were egg-positive during only one of three screenings. Thus, data presented here indicate that when individuals are screened repeatedly, infection status can be assessed more accurately, control programs can be properly evaluated, and population estimates of S. haematobium infection may be made with increased confidence, as compared with single screening.

A wavelet-based autoregressive fuzzy model for forecasting algal blooms

This paper proposes fuzzy models for forecasting the complex behavior of algal blooms. The models are developed through the integration of autoregressive models, the Takagi-Sugeno fuzzy model, and discrete wavelet transform algorithms. The premise parts of the proposed models are determined using the subtractive clustering technique and the consequent parts are optimized using weighted least squares. To train and validate the proposed fuzzy models, a large number of data sets were collected from Daecheong reservoir in Geum River in the Republic of Korea. The data include both water quality and hydrological variables. Total nitrogen, total phosphorous, dissolved oxygen, chemical oxygen demand, biochemical oxygen demand, pH, air temperature, water temperature and outflow water were evaluated as input signals while chlorophyll-a was used as an output. It is demonstrated from the simulation that the proposed fuzzy models are effective in forecasting algal blooms. Complex forecasting models are developed in this paper.Three intelligent systems for predicting behavior of algal blooms are modeled.The models are validated using experimental data.

Seasonality of water quality and diarrheal disease counts in urban and rural settings in south India.

The study examined relationships among meteorological parameters, water quality and diarrheal disease counts in two urban and three rural sites in Tamil Nadu, India. Disease surveillance was conducted between August 2010 and March 2012; concurrently water samples from street-level taps in piped distribution systems and from household storage containers were tested for pH, nitrate, total dissolved solids, and total and fecal coliforms. Methodological advances in data collection (concurrent prospective disease surveillance and environmental monitoring) and analysis (preserving temporality within the data through time series analysis) were used to quantify independent effects of meteorological conditions and water quality on diarrheal risk. The utility of a local calendar in communicating seasonality is also presented. Piped distribution systems in the study area showed high seasonal fluctuations in water quality. Higher ambient temperature decreased and higher rainfall increased diarrheal risk with temperature being the predominant factor in urban and rainfall in rural sites. Associations with microbial contamination were inconsistent; however, disease risk in the urban sites increased with higher median household total coliform concentrations. Understanding seasonal patterns in health outcomes and their temporal links to environmental exposures may lead to improvements in prospective environmental and disease surveillance tailored to addressing public health problems.

Piped water consumption in Ghana: A case study of temporal and spatial patterns of clean water demand relative to alternative water sources in rural small towns

Continuous access to adequate quantities of safe water is essential for human health and socioeconomic development. Piped water systems (PWSs) are an increasingly common type of water supply in rural African small towns. We assessed temporal and spatial patterns in water consumption from public standpipes of four PWSs in Ghana in order to assess clean water demand relative to other available water sources. Low water consumption was evident in all study towns, which manifested temporally and spatially. Temporal variability in water consumption that is negatively correlated with rainfall is an indicator of rainwater preference when it is available. Furthermore, our findings show that standpipes in close proximity to alternative water sources such as streams and hand-dug wells suffer further reductions in water consumption. Qualitative data suggest that consumer demand in the study towns appears to be driven more by water quantity, accessibility, and perceived aesthetic water quality, as compared to microbiological water quality or price. In settings with chronic under-utilization of improved water sources, increasing water demand through household connections, improving water quality with respect to taste and appropriateness for laundry, and educating residents about health benefits of using piped water should be prioritized. Continued consumer demand and sufficient revenue generation are important attributes of a water service that ensure its function over time. Our findings suggest that analyzing water consumption of existing metered PWSs in combination with qualitative approaches may enable more efficient planning of community-based water supplies and support sustainable development.

Environmental Review & Case Study: Evaluating the Significance of Certain Pharmaceuticals and Emerging Pathogens in Raw Water Supplies

Pharmaceuticals and personal care products (PPCPs) are environmental contaminants introduced by the activities of man. PPCPs are not new or emerging from the perspective of knowing about them, but they are of growing interest due to reports in the popular media on occurrence and environmental impacts. As a result, PPCPs may be deemed as emerging issues by the public and utilities. Likewise, the biological constituents are not new—but, for reasons that are unclear, certain ones appear to pose a greater risk to consumers today than they have in the past. Similarly, Cryptosporidium parvum did not appear to pose a risk until 400,000 people became ill, and approximately 100 people died of cryptosporidiosis in Milwaukees water service area in 1993. Today, regulators and public health scientists are trying to identify microbes that pose a similar risk in the future. If these constituents occur in raw water supplies, they may need monitoring and treatment prior to these waters entering the potable water distribution system. The Contaminant Candidate List (CCL) developed by United States Environmental Protection Agency outlines a series of biological contaminants of concern that are not currently regulated but may pose a threat. Should these contaminants move from the CCL to a regulatory framework, water supply utilities will incur added monitoring and testing of their water supply sources, and potentially added monitoring and treatment costs in their operations.

Evaluation of coastal ocean discharges and environmental impacts in southeast Florida.

This article outlines the current literature regarding anthropogenic inputs of nutrients and microorganisms into the coastal oceans. The concern about nutrients and microorganisms in coastal marine waters is that they may cause a shift in local populations of organisms and encourage invasive algae and coral diseases. The lack of baseline data on marine populations makes it difficult to determine the source of marine population shifts. This report focuses on the question of whether there is sufficient data to implicate coastal ocean outfall discharges of secondary treated wastewater effluent in southeast Florida as a causative agent in impacts to coastal communities. The literature does not appear to support evidence of population shifts from any particular source.

Indicators of improved water access in the context of schistosomiasis transmission in rural Eastern Region, Ghana

Populations with poor access to water, sanitation and hygiene (WASH) infrastructure are disproportionately affected by the neglected tropical diseases (NTDs). As a result, WASH has gained increasing prominence in integrated control and elimination of NTDs, including schistosomiasis. In order to identify underserved populations, relevant measures of access to WASH infrastructure at sub-national or local levels are needed. We conducted a field survey of all public water sources in 74 rural communities in the Eastern Region of Ghana and computed indicators of water access using two methods: one based on the design capacity and another on the spatial distribution of water sources. The spatial method was applied to improved and surface water sources. According to the spatial method, improved water sources in the study area were well-distributed within communities with 95% (CI95%: 91, 98) of the population having access within 500m when all, and 87% (CI95%: 81, 93) when only functional water sources were considered. According to the design capacity-based method, indicator values were lower: 63% (CI95%: 57, 69) for all and 49% (CI95%: 43, 55) for only functional sources. Surface water access was substantial with 62% (CI95%: 54, 71) of the population located within 500m of a perennial surface water source. A negative relationship was observed between functional improved water access and surface water access within 300m. In this context, perceived water quality of the improved sources was also important, with a 17% increase in surface water access in towns with one reported water quality problem as compared to towns with no problems. Our study offers a potential methodology to use water point mapping data to identify communities in need of improved water access to achieve schistosomiasis risk reduction.

Physicochemical parameters affecting the perception of borehole water quality in Ghana

Rural Ghanaian communities continue using microbiologically contaminated surface water sources due in part to undesirable organoleptic characteristics of groundwater from boreholes. Our objective was to identify thresholds of physical and chemical parameters associated with consumer complaints related to groundwater. Water samples from 94 boreholes in the dry season and 68 boreholes in the rainy season were analyzed for 18 parameters. Interviews of consumers were conducted at each borehole regarding five commonly expressed water quality problems (salty taste, presence of particles, unfavorable scent, oily sheen formation on the water surface, and staining of starchy foods during cooking). Threshold levels of water quality parameters predictive of complaints were determined using the Youden index maximizing the sum of sensitivity and specificity. The probability of complaints at various parameter concentrations was estimated using logistic regression. Exceedances of WHO guidelines were detected for pH, turbidity, chloride, iron, and manganese. Concentrations of total dissolved solids (TDS) above 172mg/L were associated with salty taste complaints. Although the WHO guideline is 1000mg/L, even at half the guideline, the likelihood of salty taste complaint was 75%. Iron concentrations above 0.11, 0.14 and 0.43mg/L (WHO guideline value 0.3mg/L) were associated with complaints of unfavorable scent, oily sheen, and food staining, respectively. Iron and TDS concentrations exhibited strong spatial clustering associated with specific geological formations. Improved groundwater sources in rural African communities that technically meet WHO water quality guidelines may be underutilized in preference of unimproved sources for drinking and domestic uses, compromising human health and sustainability of improved water infrastructure.