Viruses In Surface Waters Research Articles

Safeguarding reverse osmosis membrane integrity in drinking water production: A pilot study using 2 native bacterial communities and viruses in surface water as integrity indicators

Water treatment train including a reverse osmosis barrier is capable of producing high-quality water coupled with microbial safety. However, analytically proving this with log removal value (LRV) > 3 has remained a challenge. Conservative techniques that quantify salt or sulfate ion passage as virus surrogates are currently used to credit the membrane system for its microbial removal capacity. These methods are insensitive, and it is now understood that the transport mechanism correlation between these surrogates with the actual passage of viruses is weak. There is also a huge gap between the current log credit assigned (using spiking of surrogates in feed) and the actual log removal that can be proven in the drinking water plant. In this paper, we introduce two techniques that exploit the high concentration of microbial communities in fresh surface water by quantifying bacteria through flow cytometry (FC) and native viruses through qPCR assays. These two methods are compared to LRV of conductivity, TOC, and fluorescent markers. That high concentration of bacterial community allowed for LRV > 4 by flow cytometry in an intact module. After inflicting damage with a 1.5 mm defect, the FC method detected the damage, and a bacterial cell count >103 cell count/ml was measured in the permeate, while conductivity lacked sensitivity to monitor any integrity loss. Furthermore, after chlorine exposure to the membrane, both bacteria and virus detected no leakage, proving the membrane's intactness and also demonstrating the effect of chlorination on the passage of small solutes. The implementation of the two microbial quantifying methods in full-scale water treatment plants facilitates higher sensitivity in membrane integrity loss than currently used methods.

Potential risk of plant viruses entering disease cycle in surface water in protected vegetable growing areas of Eastern China.

With the expansion of protected vegetable growing areas (PVGAs), viral plant diseases have become more prevalent, causing severe economic losses to the vegetable production industry in China. At present, researches on plant viruses mainly focus on plants, but there is only a few reports on the species of viruses in surface water from PVGAs. The surface water samples in PVGAs are representative to a certain extent, which has an important reference value for studying the characteristics of plant viruses in surface water. The purpose of this study was to identify the diversity and the possibility of entering disease infection cycle of plant viruses in water samples collected from PVGAs in eastern China. A total of 144 water samples were collected, and eight plant viruses including tobacco mosaic virus (TMV, 8.33%), cucumber green mottle mosaic virus (CGMMV, 33.33%), pepper mild mottle virus (PMMoV, 6.94%), cucumber mosaic virus (CMV, 0.69%), tomato masaic virus (ToMV, 3.47%), tomato mottle mosaic virus (ToMMV, 0.69%), tomato chlorosis virus (ToCV, 4.17%), and tomato yellow leaf curl virus (TYLCV, 5.56%) were examined using RT-PCR and PCR. The species of viruses in surface water varied greatly by location. CGMMV, TMV, ToCV, ToMV, ToMMV, and TYLCV were identified in Shandong, a northern part of Eastern China, whereas only PMMoV was found in Shanghai, a southern part of Eastern China. After healthy tobacco plants were inoculated with the concentrated solutions of TMV, ToMV, CGMMV, and PMMoV, could cause disease in healthy tobacco, indicating that the plant viruses in the concentrated solution have the infectivity, and the plant viruses in surface water have the possibility of entering the infection cycle of disease. The results will improve the understanding of the potential risks of waterborne disease transmission.

Seasonal prevalence of potentially infectious enteric viruses in surface waters below treated wastewater discharge.

Enteric viruses are widely distributed in the natural water environment. The aim of the study was to assess the prevalence of potentially infectious adenoviruses (AdV) and rotaviruses (RoV) in surface water near treated wastewater discharge. Water samples were collected from surface water below the treated wastewater effluent discharge located near a wastewater treatment plant receiving sewage from an urban area. Water samples were concentrated by ultrafiltration and treated with propidium monoazide dye, followed with v-qPCR/v-RT-qPCR analysis. Simultaneously, the temperature and pH of the collected samples were measured to check the influence of these parameters on the concentrations of potentially infectious viruses. The average concentrations of potentially infectious AdV and RoV particles in collected samples ranged between log10 1.86 ÷ 3.94 gc/L and log10 2.39 ÷ 3.82 gc/L in the winter season, and between log10 2.18 ÷ 3.59 gc/L and log10 1.85 ÷ 2.10 gc/L in the summer season, respectively. In general, AdVs were detected more often than RoVs, while RoV-positive samples were more frequent in the winter than in the summer season (Chi2: p = 0.028; Fisher's Exact test p = 0.033). Negative correlations between log10 concentration of viral particles and temperature and pH for both viruses were observed. The presence of potentially infectious AdVs and RoVs in the surface waters may constitute a health risk for the local population. Application of v-PCR-based methods and considering AdV as a viral contamination indicator should be introduced into virological water quality monitoring for estimations of public health risks.

Quantitative RT-PCR detection of human noroviruses and hepatitis A virus in fresh produce and surface water used for irrigation in the Mansoura and Giza regions, Egypt.

Surface water used as an irrigation source can be a significant source of viral contamination of fresh produce. Enteric viruses such as hepatitis A virus (HAV) and human norovirus genogroup I (HNoV GI) and genogroup II (HNoV GII) can be transmitted to human via fresh produce when irrigated with contaminated water or when prepared by infected food handlers. In the current study, we investigated the presence of HAV, HNoV GI and GII in fresh produce and surface water used in cultivation of this produce using real-time PCR. Samples were collected from six different points in the Mansoura and Giza regions, Egypt. Our analysis showed that at least one virus was found in 41.6% (30/72) of surface water samples and 27% (13/48) of fresh produce samples. HAV (23/72) with a mean viral concentration = 4 × 106 genome copies/litre (GC/L) was the most frequently identified virus in surface water samples, followed by human norovirus genogroup II (HNoV GII) (15/72, with a mean concentration = 1.2 × 106 GC/L, and human noroviruses genogroup I (HNoV GI) (12/72, with a mean concentration = 1.4 × 104 GC/L). Additionally, HAV (10/48) with a mean concentration = 5.2 × 105 genome copies/gram (GC/g) was also the most frequently detected virus in the fresh produce samples, followed by HNoV GII (8/48, with a mean concentration = 1.7 × 104 GC/g); meanwhile, HNoV GI (6/48) was less detected virus with a mean concentration = 3 × 103 GC/g. This work suggests a wide prevalence of human enteric viruses in surface waters and fresh produce, which is of concern when the fresh produce is eaten raw. Thus, additional monitoring for viral pathogens in irrigation water and food is needed to increase the awareness of this issue to rise the control measures to reduce illness from contaminated food.

Application of Capsid Integrity (RT-)qPCR to Assessing Occurrence of Intact Viruses in Surface Water and Tap Water in Japan

Capsid integrity (RT-)qPCR has recently been developed to discriminate between intact forms from inactivated forms of viruses, but its applicability to identifying integrity of viruses in drinking water has remained limited. In this study, we investigated the application of capsid integrity (RT-)qPCR using cis-dichlorodiammineplatinum (CDDP) with sodium deoxycholate (SD) pretreatment (SD-CDDP-(RT-)qPCR) to detect intact viruses in surface water and tap water. A total of 63 water samples (surface water, n = 20; tap water, n = 43) were collected in the Kanto region in Japan and quantified by conventional (RT)-qPCR and SD-CDDP-(RT-)qPCR for pepper mild mottle virus (PMMoV) and seven other viruses pathogenic to humans (Aichivirus (AiV), noroviruses of genotypes I and II, enterovirus, adenovirus type 40 and 41, and JC and BK polyomaviruses). In surface water, PMMoV (100%) was more frequently detected than other human pathogenic viruses (30%–60%), as determined by conventional (RT-)qPCR. SD-CDDP-(RT-)qPCR also revealed that intact PMMoV (95%) was more common than intact human pathogenic viruses (20%–45%). In the tap water samples, most of the target viruses were not detected by conventional (RT-)qPCR, except for PMMoV (9%) and AiV (5%). PMMoV remained positive (5%), whereas no AiV was detected when tested by SD-CDDP-(RT-)qPCR, indicating that some PMMoV had an intact capsid, whereas AiV had damaged capsids. The presence of AiV in the absence of PMMoV in tap water produced from groundwater may demonstrate the limitation of PMMoV as a viral indicator in groundwater. In addition to being abundant in surface water, PMMoV was detected in tap water, including PMMoV with intact capsids. Thus, the absence of intact PMMoV may be used to guarantee the viral safety of tap water produced from surface water.

Occurrence of Enteric Viruses in Surface Water and the Relationship with Changes in Season and Physical Water Quality Dynamics

Environmental water quality issues have dominated global discourse and studies over the past five decades. Significant parameters of environmental water quality include changes in biological and physical parameters. Some of the biological parameters of significance include occurrence of enteric viruses. Enteric viruses can affect both human and animal's health by causing diseases such as gastrointestinal and respiratory infections. In this study, the relationship between the occurrence of enteric viruses with reference to adenoviruses and enteroviruses and the physical water quality characteristics was assessed from water samples collected from Lake Victoria (LV) in Kenya. In order to understand the dynamics of season driven enteric viruses' contamination of the lake waters, we additionally analysed seasonal behavior of the lake's catchment area in terms of rainfall effects. Physical quality parameters were measured on-site while viral analysis was carried out by molecular methods using the nested polymerase chain reaction (nPCR). From 216 samples that were analysed for viral contamination, enteric viral genomes were discovered in 18 (8.3%) of the samples. Out of half of the samples (108) collected during the rainy season, enteric viral genomes were detected in 9.26% (10) while 8 (7.41%) samples tested positive from the other half of the samples (108) collected during the dry season. There was, however, no significant correlation noted between the physical water quality characteristics and the enteric viruses' occurrence. Neither wet season nor dry season was significantly associated with the prevalence of the viruses. In Lake Victoria waters, most of the samples had an average of physical water quality parameters that were within the range accepted by the World Health Organization (WHO) for surface waters with exemption of turbidity which was above the recommended 5 NTU as recorded from some sampling sites. Continuous and long-term surveillance of the lake water to accurately monitor the contaminants and possible correlation between chemical, physical, and biological characteristics is recommended. This would be important in continuous understanding of the hydrological characteristics changes of the lake for proper management of its quality with reference to the WHO standards. A multiple varied-sampling approach in different geographical regions during different seasons is recommended to establish the geographical distribution and relatedness to seasonal distribution patterns of the viruses. The data generated from this study will be useful in providing a basis for assessment of seasonally driven fecal pollution load of the lake and enteric virus contamination for proper management of the sanitary situation around the lake.

Environmental surveillance of human enteric viruses in wastewaters, groundwater, surface water and sediments of Campania Region

Enteric viruses represent a public health risk since they are involved in foodborne and waterborne outbreaks. The aim of this study was to investigate the circulation of select human enteric viruses — hepatitis A virus (HAV), noroviruses (NoVGI and NoVGII), adenovirus (AdV), rotavirus (RV), astrovirus (AsV), sapovirus (SaV) and aichivirus (AiV) – in wastewater and in environmental samples (groundwater, surface water and sediments) of Campania Region, southern Italy, with the goal of evaluating their circulation in the environment and to characterize the circulating strains by phylogenetic analysis. A total of 199 water and sediment samples were collected from rivers, dams, wells and wastewater treatment plants (WWTPs) in all provinces of the Campania Region and analysed by real-time qPCR for the detection of viruses, after a concentration step with organic flocculation. This study provides information on the qualitative and quantitative spread of human enteric viruses in the environment and their potential health risk. In our samples all the viral families were detected, with different prevalence. Among the investigated viruses, RV was the most prevalent and concentrated virus in surface water and sediments, with AsV being prevalent and concentrated in wastewater. The prevalence of viral pathogens was not influenced by season for almost all enteric viruses, except for NoVGII in WWTPs. Within the WWTPs, a significant reduction in the average concentration levels was observed for all viral targets from the influent to the effluent except for the HAV and AiV. The results of our study confirmed the importance of environmental surveillance that can represent a key tool for pollution control and human risk exposure.

Total coliforms as an indicator of human enterovirus presence in surface water across Tianjin city, China

BackgroundEnteric viruses in surface water pose considerable risk to morbidity in populations living around water catchments and promote outbreaks of waterborne diseases. However, due to poor understanding of the correlation between water quality and the presence of human enteric viruses, the failure to assess viral contamination through alternative viral indicators makes it difficult to control disease transmission.MethodsWe investigated the occurrence of Enteroviruses (EnVs), Rotaviruses (HRVs), Astroviruses (AstVs), Noroviruses GII (HuNoVs GII) and Adenoviruses (HAdVs) from Jinhe River over 4 years and analyzed their correlation with physicochemical and bacterial parameters in water samples.ResultsThe findings showed that all target viruses were detected in water at frequencies of 91.7% for HAdVs, 81.3% for HuNoVs GII, 79.2% for EnVs and AstVs, and 70.8% for HRVs. These viruses had a seasonal pattern, which showed that EnVs were abundant in summer but rare in winter, while HAdVs, HRVs, AstVs, and HuNoVs GII exhibited opposite seasonal trends. Pearson correlation analysis showed that total coliforms (TC) was significantly positively correlated with EnVs concentrations while no consistent significant correlations were observed between bacterial indices and viruses that precipitate acute gastroenteritis.ConclusionsTaken together, the findings provide insights into alternative viral indicators, suggesting that TC is a potentially promising candidate for assessment of EnVs contamination. However, it failed to predict the presence of HAdVs, HRVs, AstVs, and HuNoVs GΙΙ in surface water across the city of Tianjin.

Human-Associated Indicator Bacteria and Human-Specific Viruses in Surface Water: A Spatial Assessment with Implications on Fate and Transport.

Hydrologic, seasonal, and spatial variability of sewage contamination was studied at six locations within a watershed upstream from water reclamation facility (WRF) effluent to define relative loadings of sewage from different portions of the watershed. Fecal pollution from human sources was spatially quantified by measuring two human-associated indicator bacteria (HIB) and eight human-specific viruses (HSV) at six stream locations in the Menomonee River watershed in Milwaukee, Wisconsin from April 2009 to March 2011. A custom, automated water sampler, which included HSV filtration, was deployed at each location and provided unattended, flow-weighted, large-volume (30-913 L) sampling. In addition, wastewater influent samples were composited over discrete 7 day periods from the two Milwaukee WRFs. Of the 8 HSV, only 3 were detected, present in up to 38% of the 228 stream samples, while at least 1 HSV was detected in all WRF influent samples. HIB occurred more often with significantly higher concentrations than the HSV in stream and WRF influent samples ( p < 0.05). HSV yield calculations showed a loss from upstream to the most-downstream sub-watershed of the Menomonee River, and in contrast, a positive HIB yield from this same sub-watershed emphasizes the complexity in fate and transport properties between HSV and HIB. This study demonstrates the utility of analyzing multiple HSV and HIB to provide a weight-of-evidence approach for assessment of fecal contamination at the watershed level, provides an assessment of relative loadings for prioritizing areas within a watershed, and demonstrates how loadings of HSV and HIB can be inconsistent, inferring potential differences in fate and transport between the two indicators of human fecal presence.

Enteric Viruses in Surface Waters from Argentina: Molecular and Viable-Virus Detection.

Water resources contaminated with wastewater are an important source for the dissemination of enteric viruses with an impact on the health of the population. The aim of the study was to assess the viral contamination of freshwater from a dam in Argentina by using infectious enterovirus detection, viral RNA amplification, and a genetic characterization of five enteric viruses associated with diarrhea and hepatitis. Enterovirus infectivity (iEV) was evaluated by cell culture and direct immunofluorescence. The detection of the viral genome of rotavirus (RV), human astrovirus (HAstV), norovirus (NoV), hepatitis A virus (HAV), and hepatitis E virus (HEV) was performed by reverse transcriptase PCR (RT-PCR). A total of 48 water samples from 4 monitoring points on the body of the dam from January to December 2012 and 66 water samples from 3 tourist beaches on the edge of the dam from October 2013 to October 2015 were collected monthly. During the first period, the overall viral frequency detection was 52.1% for group A RV, 50% for HAstV, 60.4% for NoV, 22.9% for HAV, 2.1% for HEV, and 64.6% for iEV. The overall frequency detection for the second sampling was 18.2% for RV and HAstV, 31.8% for NoV, 7.57% for HEV, and 66.7% for iEV. There was no detection of HAV during this period. The genotypes and genogroups detected through the study correlated with the most common genomic variants associated with human gastrointestinal and hepatitis illnesses. The results obtained could alert the health systems and environmental sanitation to make decisions for viral control and prevention in our environment.IMPORTANCE The study shows the impact of anthropic contamination of one of the most important tourist water resources in Argentina. This course of recreational water would be a favorable scenario for infection, as well as a reservoir for the enteric viruses, creating a risk for the population exposed to these waters. The results obtained could alert the health systems and environmental sanitation to make decisions for the control and prevention of viral diseases in this environment.

Wastewater contamination in Antarctic melt-water streams evidenced by virological and organic molecular markers

Human activities in the Antarctica including tourism and scientific research have been raised substantially in the last century with the concomitant impact on the Antarctic ecosystems through the release of wastewater mainly from different scientific stations activities. The aim of this study was to assess the wastewater contamination of surface waters and sediments of three melt-water streams (11 sites) by leaking septic tanks located in the vicinity of the Uruguayan Scientific Station in the Fildes Peninsula, King George Island, Antarctica, during summer 2015. For this purpose, we combined the analysis of fecal steroids in sediments by using gas chromatography and six enteric viruses in surface waters by quantitative and qualitative PCR. Coprostanol concentrations (from 0.03 to 3.31μgg−1) and fecal steroids diagnostic ratios indicated that stations C7 and C8 located in the kitchen stream presented sewage contamination. Rotavirus was the only enteric virus detected in five sites with concentration ranging from 1.2×105gcL−1 to 5.1×105gcL−1 being three of them located downstream from the leaking AINA and Kitchen septic tanks. This study shows for the first time the presence of both virological and molecular biomarkers of wastewater pollution in surface waters and sediments of three melt-water streams in the vicinity of a scientific station in the Antarctica. These results highlight the importance of the complementation of these biomarkers in two different matrices (surface waters and sediments) to assess wastewater pollution in an Antarctic environment related to anthropogenic activities in the area.

The Impact of the Extreme Amazonian Flood Season on the Incidence of Viral Gastroenteritis Cases.

During the Amazonian flood season in 2012, the Negro River reached its highest level in 110years, submerging residential and commercial areas which appeared associated with an elevation in the observed gastroenteritis cases in the city of Manaus. The aim of this study was to evaluate the microbiological water quality of the Negro River basin during this extreme flood to investigate this apparent association between the illness cases and the population exposed to the contaminated waters. Forty water samples were collected and analysed for classic and emerging enteric viruses. Human adenoviruses, group A rotaviruses and genogroup II noroviruses were detected in 100, 77.5 and 27.5% of the samples, respectively, in concentrations of 103-106 GC/L. All samples were compliant with local bacteriological standards. HAdV2 and 41 and RVA G2, P[6], and P[8] were characterised. Astroviruses, sapoviruses, genogroup IV noroviruses, klasseviruses, bocaviruses and aichiviruses were not detected. Statistical analyses showed correlations between river stage level and reported gastroenteritis cases and, also, significant differences between virus concentrations during this extreme event when compared with normal dry seasons and previous flood seasons of the Negro River. These findings suggest an association between the extreme flood experienced and gastrointestinal cases in the affected areas providing circumstantial evidence of causality between the elevations in enteric viruses in surface waters and reported illness.

In Situ Dynamics of F-Specific RNA Bacteriophages in a Small River: New Way to Assess Viral Propagation in Water Quality Studies

The occurrence and propagation of enteric viruses in rivers constitute a major public health issue. However, little information is available on the in situ transport and spread of viruses in surface water. In this study, an original in situ experimental approach using the residence time of the river water mass was developed to accurately follow the propagation of F-specific RNA bacteriophages (FRNAPHs) along a 3-km studied river. Surface water and sediment of 9 sampling campaigns were collected and analyzed using both infectivity and RT-qPCR assays. In parallel, some physico-chemical variables such as flow rate, water temperature, conductivity and total suspended solids were measured to investigate the impact of environmental conditions on phage propagation. For campaigns with low flow rate and high temperature, the results highlight a decrease of infectious phage concentration along the river, which was successfully modelled according to a first-order negative exponential decay. The monitoring of infectious FRNAPHs belonging mainly to the genogroup II was confirmed with direct phage genotyping and total phage particle quantification. Reported k decay coefficients according to exponential models allowed for the determination of the actual in situ distance and time necessary for removing 90 % of infectious phage particles. This present work provides a new way to assess the true in situ viral propagation along a small river. These findings can be highly useful in water quality and risk assessment studies to determine the viral contamination spread from a point contamination source to the nearest recreational areas.

A theoretical approach to using faecal indicator data to model norovirus concentration in surface water for QMRA: Glomma River, Norway

Monitoring of faecal indicator organisms, such as Escherichia coli, in environmental and drinking waters is inadequate for the protection public health, primarily due to the poor relationship between E. coli and the occurrence of human pathogens, especially viruses, in environmental samples. Nevertheless, measurements of faecal indicator organisms within the risk based approach, can provide valuable information related to the magnitude and variability of faecal contamination, and hence provide insight into the expected level of potential pathogen contamination. In this study, a modelling approach is presented that estimates the concentration of norovirus in surface water relying on indicator monitoring data, combined with specific assumptions regarding the source of faecal contamination. The model is applied to a case study on drinking water treatment intake from the Glomma River in Norway. Norovirus concentrations were estimated in two sewage sources discharging into the river upstream of the drinking water offtake, and at the source water intake itself. The characteristics of the assumed source of faecal contamination, including the norovirus prevalence in the community, the size of the contributing population and the relative treatment efficacy for indicators and pathogens in the sewage treatment plant, influenced the magnitude and variability in the estimated norovirus concentration in surface waters. The modelling exercise presented is not intended to replace pathogen enumeration from environmental samples, but rather is proposed as a complement to better understand the sources and drivers of viruses in surface waters. The approach has the potential to inform sampling regimes by identifying when the best time would be to collect environmental samples; fill in the gaps between sparse datasets; and potentially extrapolate existing datasets in order to model rarer events such as an outbreak in the contributing population. In addition, and perhaps most universally, in the absence of pathogen data, this approach can be used as a first step to predict the source water pathogen concentration under different contamination scenarios for the purpose of quantifying microbial risks.

Enteric viruses in surface water and sediment samples from the catchment area of Peri Lagoon, Santa Catarina State, Brazil.

This paper aims to quantify human adenovirus (HAdV), rotavirus species A (RVA), and hepatitis A virus (HAV) in surface water and sediments and to determine the viability of HAdV in these samples. Water and sediment samples were collected, and HAdV, RVA, and HAV were quantified by real-time polymerase chain reaction (PCR); HAdV was also evaluated for infectivity by a plaque assay (PA). For the water samples, HAdV was detected in 70.8% of the summer collections, with 82.4% containing infectious HAdV; the HAdV incidence in winter was 62.5%. For the sediment samples, the incidence of HAdV was 37.5% in the summer collections, with 66.7% containing infectious HAdV; the HAdV incidence in winter was 37.5%. RVA was detected in 20.8 and 45.8% of surface water samples collected in summer and winter, respectively, and 8.3 and 12.5% of sediment samples collected in summer and winter, respectively. HAV was detected only in surface waters, with 54.8 and 12.5% positivity in summer and winter samples, respectively. This study demonstrated that enteric viruses are present in water and sediments and that the presence of infectious viruses should be investigated whenever possible for quantitative microbial risk assessment studies. Combined analyses of water and sediments are important for reliable public health risk analysis of recreational and lagoon waters.

Entero- and parechovirus distributions in surface water and probabilities of exposure to these viruses during water recreation

Numerous studies have reported quantitative data on viruses in surface waters generated using different methodologies. In the current study, the impact of the use of either cell culture-based or molecular-based methods in quantitative microbial risk assessment was assessed. Previously and newly generated data on the presence of infectious human enteroviruses (HEV) and enterovirus and parechovirus RNA were used to estimate distributions of virus concentrations in surface waters. Because techniques for the detection of infectious human parechoviruses (HPeV) in surface waters were not available, a ‘Parallelogram Approach’ was used to estimate their concentrations based on the ratio infectious HEV/HEV RNA. The obtained virus concentrations were then used to estimate the probability of exposure for children during recreation in such virus contaminated surface waters.Human enterovirus cell culture/PCR ratios ranged from 2.3 × 10−3 to 0.28. This broad range of ratios indicates that care should be taken in assuming a fixed ratio for assessing the risk with PCR based virus concentrations.The probabilities of exposure to both enteroviruses and parechoviruses were calculated, using our Parallelogram Approach for the calculation of infectious parechoviruses. For both viruses it was observed that the detection method significantly influenced the probability of exposure. Based on the calculated culture data, PCR data, and the ingestion volume, it was estimated that the mean probabilities of exposure, of recreating children, to surface water containing viruses were 0.087 (infectious enteroviruses), 0.71 (enterovirus particles), 0.28 (parechovirus particles) and 0.025 (calculated infectious parechoviruses) per recreation event. The mean probabilities of exposure of children recreating in surface water from which drinking water is produced to infectious enteroviruses were estimated for nine locations and varied between 1.5 × 10−4 – 0.09 per recreation event.In this study, the use of the rotavirus dose response relationship as a surrogate was avoided. Instead, the probabilities of exposure were derived as a function of the distributions of the calculated doses. Our ‘Parallelogram Approach’ was used to estimate the unavailable infectious parechovirus concentrations using Monte Carlo simulations, and the exposure assessment carried out showed that virus concentrations present in surface waters could pose a health risk for children and other vulnerable populations.

Presence of Human and Animal Viruses in Surface Waters in Vojvodina Province of Serbia.

For the first time in Serbia, a small surveillance study was conducted in order to estimate the presence and frequency of occurrence of selected human [adenoviruses (HAdV), noroviruses, (NoV GI, NoV GII) and hepatitis A virus (HAV)], animal [porcine adenovirus (PAdV) and bovine polyomavirus (BPyV)] and zoonotic [hepatitis E virus (HEV)] viruses in selected surface waters. In total, 60 surface water samples were collected in two sampling occasions at 30 locations, with each sampling time being separated by 1-5months. In addition, six sewage effluent samples were collected at one sampling site per each of the three tested town sewage systems, in two sampling occasions with 2months intervals, before their discharge into the surface waters. The most prevalent virus found was HAdV which was detected in 43.33% samples. NoV GII was found in 40% samples. NoV GI was found in 10% samples, and PAdV, BPyV and HEV were detected in 5 (8.33%), 4 (6.67%) and 2 (3.33%) samples, respectively. HAV was not found in any of analysed surface waters or urban sewage samples. The obtained results confirm the presence of pathogenic enteric viruses of both human and animal origin in surface waters in Serbia indicating the existence of diverse contamination sources.

Sunlight inactivation of viruses in open-water unit process treatment wetlands: modeling endogenous and exogenous inactivation rates.

Sunlight inactivation is an important mode of disinfection for viruses in surface waters. In constructed wetlands, for example, open-water cells can be used to promote sunlight disinfection and remove pathogenic viruses from wastewater. To aid in the design of these systems, we developed predictive models of virus attenuation that account for endogenous and exogenous sunlight-mediated inactivation mechanisms. Inactivation rate models were developed for two viruses, MS2 and poliovirus type 3; laboratory- and field-scale experiments were conducted to evaluate the models' ability to estimate inactivation rates in a pilot-scale, open-water, unit-process wetland cell. Endogenous inactivation rates were modeled using either photoaction spectra or total, incident UVB irradiance. Exogenous inactivation rates were modeled on the basis of virus susceptibilities to singlet oxygen. Results from both laboratory- and field-scale experiments showed good agreement between measured and modeled inactivation rates. The modeling approach presented here can be applied to any sunlit surface water and utilizes easily measured inputs such as depth, solar irradiance, water matrix absorbance, singlet oxygen concentration, and the virus-specific apparent second-order rate constant with singlet oxygen (k2). Interestingly, the MS2 k2 in the open-water wetland was found to be significantly larger than k2 observed in other waters in previous studies. Examples of how the model can be used to design and optimize natural treatment systems for virus inactivation are provided.

Pepper mild mottle virus as an indicator and a tracer of fecal pollution in water environments: Comparative evaluation with wastewater-tracer pharmaceuticals in Hanoi, Vietnam

We analyzed pepper mild mottle virus (PMMoV) in 36 samples taken from surface water, wastewater, groundwater, tap water and bottled water in Hanoi, Vietnam. We then compared the occurrence and fates of PMMoV with pharmaceuticals and personal care products (PPCPs), which are known wastewater tracers. PMMoV was detected in 94% of the surface water samples (ponds, water from irrigated farmlands and rivers) and in all the wastewater samples. The PMMoV concentration ranged from 5.5×106–7.2×106copies/L in wastewater treatment plant (WWTP) influents, 6.5×105–8.5×105copies/L in WWTP effluents and 1.0×104–1.8×106copies/L in surface water. Among the sixty PPCPs analyzed, caffeine and carbamazepine had high detection rates in surface water (100% and 88%, respectively). In surface water, the concentration ratio of PMMoV to caffeine remained unchanged than that in WWTP influents, suggesting that the persistence of PMMoV in surface water was comparable to that of caffeine. The persistence and the large concentration ratio of PMMoV in WWTP influents to the method detection limit would account for its ubiquitous detection in surface water. In comparison, human enteric viruses (HEV) were less frequently detected (18–59%) than PMMoV in surface water, probably because of their faster decay. Together with the reported high human feces-specificity, our results suggested that PMMoV is useful as a sensitive fecal indicator for evaluating the potential occurrence of pathogenic viruses in surface water. Moreover, PMMoV can be useful as a moderately conservative fecal tracer for specifically tracking fecal pollution of surface water. PMMoV was detected in 38% of the groundwater samples at low concentrations (up to 19copies/L). PMMoV was not detected in the tap water and bottled water samples. In groundwater, tap water and bottled water samples, the occurrence of PPCPs and HEV disagreed with that of PMMoV, suggesting that PMMoV is not suitable as an indicator or a tracer in those waters.

Human and bovine viruses in the Milwaukee River watershed: Hydrologically relevant representation and relations with environmental variables

To examine the occurrence, hydrologic variability, and seasonal variability of human and bovine viruses in surface water, three stream locations were monitored in the Milwaukee River watershed in Wisconsin, USA, from February 2007 through June 2008. Monitoring sites included an urban subwatershed, a rural subwatershed, and the Milwaukee River at the mouth. To collect samples that characterize variability throughout changing hydrologic periods, a process control system was developed for unattended, large-volume (56–2800L) filtration over extended durations. This system provided flow-weighted mean concentrations during runoff and extended (24-h) low-flow periods. Human viruses and bovine viruses were detected by real-time qPCR in 49% and 41% of samples (n=63), respectively. All human viruses analyzed were detected at least once including adenovirus (40% of samples), GI norovirus (10%), enterovirus (8%), rotavirus (6%), GII norovirus (1.6%) and hepatitis A virus (1.6%). Three of seven bovine viruses analyzed were detected including bovine polyomavirus (32%), bovine rotavirus (19%), and bovine viral diarrhea virus type 1 (5%). Human viruses were present in 63% of runoff samples resulting from precipitation and snowmelt, and 20% of low-flow samples. Maximum human virus concentrations exceeded 300genomiccopies/L. Bovine viruses were present in 46% of runoff samples resulting from precipitation and snowmelt and 14% of low-flow samples. The maximum bovine virus concentration was 11genomiccopies/L. Statistical modeling indicated that stream flow, precipitation, and season explained the variability of human viruses in the watershed, and hydrologic condition (runoff event or low-flow) and season explained the variability of the sum of human and bovine viruses; however, no model was identified that could explain the variability of bovine viruses alone. Understanding the factors that affect virus fate and transport in rivers will aid watershed management for minimizing human exposure and disease transmission.