Seasonal detection of human viruses and coliphage in Newport Bay, California

Occurrence of F-Specific Bacteriophages in Untreated and Treated Wastewaters in Mumbai

F + coliphages are considered as potential enteric viral indicators in water systems as a tool for on-site validation of wastewater treatment processes. The present study evaluated the occurrence of F + coliphages in wastewaters collected from three wastewater treatment plants (WWTPs) in Mumbai city, to assess this potential. The detection and enumeration of F + coliphages was carried out from WWTPs Z1, Z3 and Z5 using the ISO 10705-1 and U.S EPA 1601 methods. F + coliphages were majorly detected in untreated wastewater samples followed by a few secondary treated samples in WWTP-Z1 and Z3 and one tertiary treated sample from Z1, these differences were found to be statistically significant. The difference in F + coliphage levels between the treatment stages highlight their potential as indicators for monitoring the efficiency of wastewater treatment. The overall positivity of F + coliphage was 35.09% for Salmonella. typhimurium WG49 host (as per ISO 10705-1), was higher by 10.52% for Escherichia coli Famp HS host (as per U.S EPA 1601) (45.61%), highlighting the efficiency of the latter host over the former in F + coliphage detection. Significant difference in F + coliphage counts using the two bacterial hosts were observed in WWTP-Z3 (p = 0.001) and WWTP-Z1 (p = 0.047) but not in WWTP-Z5 (p = 0.332).

Supplementary Information

The online version contains supplementary material available at 10.1007/s12088-023-01181-7.

Improved virus concentration methods for wash waters from decontamination of permeable and non-permeable surfaces

Surface decontamination is a method of using wash water to decontaminated surfaces preventing transmission of biological contaminants that can pose potential health risks to responders and the public. However, the risks associated with handling used wash water are largely unknown due to the lack of effective methodology to screen for pathogenic microorganisms present in these samples, especially viral pathogens. This study adapted the dead-end hollow-fiber ultrafiltration (D-HFUF) system to wash waters, including a separate procedure for recovering particle attached viruses. Simulated wash water was created using dechlorinated tap water containing a mild surfactant (0.05 % Tween 80). To determine virus recovery efficiencies, measured amounts of somatic and F+ coliphage were spiked into 2-liter volumes of wash water under the following scenarios: (1) wash water was amended with a measured amount of sterile river sediment with no sediment separation prior to filter concentration; or (2) sediment added to wash water was allowed to settle prior to filter concentrating clarified liquid portions, while precipitated sediment was subjected to viral extraction techniques to recover particle attached virus; and (3) the optimized method was deployed on non-porous and porous surfaces to simulate a decontamination clean-up event. Separation of sediment prior to D-HFUF significantly increased recovery of coliphages, (P = <0.0001) versus filtration of sediment and liquids simultaneously. A tryptic soy broth (TSB) elution solution was significantly more effective (P = ≤0.010) for recovery of both somatic and F+ coliphage, (108 ± 9 % and 92 ± 9 %, respectively), compared to elution buffers containing various surfactants (sodium hexametaphosphate, Tween 80) for recovering particle attached virus. Simulating a biocontaminate clean-up event (using the optimized sediment separation and elution protocol) resulted in coliphage recoveries of 75-96 % (permeable surface) and 71-92 % (non-permeable surface). This procedure can be used to effectively detect viruses in used wash waters aiding in reducing risks to human health during site decontamination.

Relationship between coliphage and Enterococcus at southern California beaches and implications for beach water quality management

Coliphage have been suggested as an alternative to fecal indicator bacteria for assessing recreational beach water quality, but it is unclear how frequently and at what types of beaches coliphage produces a different management outcome. Here we conducted side-by-side sampling of male-specific and somatic coliphage by the new EPA dead-end hollow fiber ultrafiltration (D-HFUF-SAL) method and Enterococcus at southern California beaches over two years. When samples were combined for all beach sites, somatic and male-specific coliphage both correlated with Enterococcus. When examined categorically, Enterococcus would have resulted in approximately two times the number of health advisories as somatic coliphage and four times that of male-specific coliphage,using recently proposed thresholds of 60 PFU/100 mL for somatic and 30 PFU/100 mL for male-specific coliphage. Overall, only 12% of total exceedances would have been for coliphage alone. Somatic coliphage exceedances that occurred in the absence of an Enterococcus exceedance were limited to a single site during south swell events, when this beach is known to be affected by nearby minimally treated sewage. Thus, somatic coliphage provided additional valuable health protection information, but may be more appropriate as a supplement to FIB measurements rather than as replacement because: (a) EPA-approved PCR methods for Enterococcus allow a more rapid response, (b) coliphage is more challenging owing to its greater sampling volume and laboratory time requirements, and (c) Enterococcus' long data history has yielded predictive management models that would need to be recreated for coliphage.

Effectiveness of two wastewater disinfection strategies for the removal of fecal indicator bacteria, bacteriophage, and enteric viral pathogens concentrated using dead-end hollow fiber ultrafiltration (D-HFUF)

Primary influent and final effluent samples were collected from wastewater treatment plants using either chlorination or ultraviolet (UV) disinfection biweekly for one year. Paired measurements were determined for fecal indicator bacteria (Escherichia coli and enterococci), cultivated bacteriophages (somatic, F+, and CB-390 coliphage and GB-124 Bacteroides phage), human-associated viral markers (human polyomavirus [HPyV] and crAssphage), enteric pathogens (adenovirus, noroviruses genogroups I and II) as well as total infectious enteric virus. To increase the probability of detecting low concentration targets, both primary (10L) and final effluent wastewater samples (40-100 L) were concentrated using a dead-end hollow-fiber ultrafilter (D-HFUF). Despite seasonal temperature fluctuations, concentration shifts of FIB, bacteriophages, human-associated viruses, and viral pathogens measured in primary influent samples were minimal, while levels of infectious enteric virus were significantly higher in the spring and fall (P range: 0.0003-0.0409). FIB levels measured in primary influents were 1-2 log₁₀ higher than bacteriophage, human-associated viral markers (except crAssphage) and viral pathogens measured. FIB displayed the greatest sensitivity to chlorine disinfection, while crAssphage, adenoviruses and infectious enteric viruses were significantly less sensitive (P ≤ 0.0096). During UV treatment, bacteriophages F+ and GB-124 were the most resistant of the culturable viruses measured (P ≤ 0.001), while crAssphage were the most resistant (P ≤ 0.0124) overall. When UV lamps were inactive, infectious enteric viruses were significantly more resilient to upstream treatment processes than all other targets measured (P ≤ 0.0257). Similar to infectious enteric viruses and adenoviruses; GB-124, F+, and crAssphages displayed the highest resistance to UV irradiation, signaling a potential applicability as pathogen surrogates in these systems. The use of D-HFUF enhanced the ability to estimate removal of viruses through wastewater treatment, with the expectation that future applications of this method will be used to better elucidate viral behavior within these systems.

Microbial health risks associated with rotavirus and enteric bacteria in River Ala in Akure, Nigeria

AIM

This study was carried out to determine the microbial health risks associated with a surface water commonly used for bathing, drinking, domestic and irrigational activities in Akure, Nigeria.

METHODS AND RESULTS

Water samples were collected from the river from March to June, 2018. The load of enteric bacteria, somatic coliphages and rotavirus in the water samples were determined using culture-based methods and molecular technique. The physicochemical characteristics of the water samples were determined using standard methods. The risks of rotavirus, Salmonella and Shigella infections resulting from ingestion of the water from the river were estimated using dose-response model. Redundancy analysis revealed that the levels of E. coli and Salmonella were highly associated with salinity and turbidity. The risks of infection associated with rotavirus (3.3 × 10^-3 ) was higher than those associated with Salmonella (1.3 × 10^-4 ) and Shigella (1.3 × 10^-3 ), and were all above the WHO acceptable risk limit (10^-4 ).

CONCLUSION

Accidental or intentional ingestion of water from the river may pose potential risks of gastrointestinal illness to humans.

SIGNIFICANCE AND IMPACT OF STUDY

Quantitative microbial risk assessment is essential in establishing adequate water management practices that must be strictly followed in order to protect human health.

Evaluating the fate of bacterial indicators, viral indicators, and viruses in water resource recovery facilities

A year-long sampling campaign at nine water resource recovery facilities (WRRFs) was conducted to assess the treatability and fate of bacterial indicators, viral indicators, and viruses. Influent concentrations of viral indicators (male-specific and somatic coliphages) and bacterial indicators (Escherichia coli and enterococci) remained relatively constant, typically varying by one order of magnitude over the course of the year. Annual average bacterial indicator reduction ranged from 4.0 to 6.7 logs, and annual average viral indicator reduction ranged from 1.6 to 5.4 logs. Bacterial and viral indicator reduction depended on the WRRF's treatment processes, and bacterial indicator reduction was greater than viral indicator reduction for many processes. Viral reduction (adenovirus 41, norovirus GI, and norovirus GII) was more similar to viral indicator reduction than bacterial indicator reduction. Overall, this work suggests that viral indicator reduction in WRRFs is variable and depends on specific unit processes. Moreover, for the same unit treatment process, viral indicator reduction and bacterial indicator reduction can vary. PRACTITIONER POINTS: A year-long sampling campaign was conducted at nine water resource recovery facilities (WRRFs). The treatability and fate of bacterial indicators, viral indicators, and viruses were assessed. Viral indicator reduction in WRRFs is variable and depends on specific unit processes. For the same unit treatment process, viral indicator reduction and bacterial indicator reduction can vary.

Virological Quality of Urban Rivers and Hospitals Wastewaters in Addis Ababa, Ethiopia

Background:

Polluted rivers and hospital wastewater become a greater concern because of their public health and environmental hazards with high tendency to result in epidemics.

Methods and Materials:

The current study investigated 84 samples of Urban rivers and 30 samples of hospitals wastewaters in Addis Ababa, Ethiopia between February and April, 2017. The simultaneous detection of male-specific and somatic Coliphages from the samples was carried out usingEscherichia coliCB390 as the host according to the single agar layer plaque assay at public health microbiology laboratory of Ethiopian Public Health Institute.

Results:

Of the total 114 samples tested, coliphages were detected in 44 (52.4%) and 3 (10%) samples of urban rivers and hospital waste waters, respect ively. Total coliphages enumerations ranged from <1pfu/100ml to 5.2×103pfu/100ml for urban rivers and <1pfu/100ml to 4.92×103pfu/100ml for hospitals wastewaters.

Conclusion:

The detection of total coliphages in our study settings warrants the possibility that the pollution of urban rivers and hospital wastewaters may be a source for pathogenic viral infections. Unless coliphages, viral and fecal indicators are also examined in the waters by public health agencies, waterborne infections cause a major risk to public health.

'Don't put your head under water': enteric viruses in Brazilian recreational waters

Like in many other countries, virologic analyses are not routinely performed in Brazil in monitoring water quality for recreational purposes. We surveyed current research regarding viral contamination of recreational water environments in Brazil. Among the enteric viruses studied in Brazilian recreational waters, we highlight adenoviruses, rotaviruses, enteroviruses and noroviruses. Although there has been relatively little research on outbreaks related to bathing in recreational water environments in Brazil, noroviruses and adenoviruses are the viruses that are most often related to outbreaks. Better surveillance of the occurrence of enteric viruses in water could improve the assessment of risk to human health as well as indicate the sources of contamination and thus demonstrate the importance of adequate environmental sanitation.

Occurrence of coliphage in raw wastewater and in ambient water: A meta-analysis

Coliphage have been proposed as indicators of fecal contamination in recreational waters because they better reflect the persistence of pathogenic viruses in the environment and through wastewater treatment than traditional fecal indicator bacteria. Herein, we conducted a systematic literature search of peer-reviewed publications to identify coliphage density data (somatic and male-specific, or MSC) in raw wastewater and ambient waters. The literature review inclusion criteria included scope, study quality, and data availability. A non-parametric two-stage bootstrap analysis was used to estimate the coliphage distributions in raw wastewater and account for geographic region and season. Additionally, two statistical methodologies were explored for developing coliphage density distributions in ambient waters, to account for the nondetects in the datasets. In raw wastewater, the analysis resulted in seasonal density distributions of somatic coliphage (SC) (mean 6.5 log₁₀ plaque forming units (PFU)/L; 95% confidence interval (CI): 6.2-6.8) and MSC (mean 5.9 log₁₀ PFU/L; 95% CI: 5.5-6.1). In ambient waters, 49% of MSC samples were nondetects, compared with less than 5% for SC. Overall distributional estimates of ambient densities of coliphage were statistically higher for SC than for MSC (mean 3.4 and 1.0 log₁₀ PFU/L, respectively). Distributions of coliphage in raw wastewater and ambient water will be useful for future microbial risk assessments.

Detection of coliphages and human adenoviruses in a subtropical estuarine lake

Fecal indicator bacteria (FIB) have been used to assess fecal contamination in recreational water. However, enteric viruses have been shown to be more persistent in the environment and resistant to wastewater treatment than bacteria. Recently, U.S Environmental Protection Agency has proposed the use of coliphages as viral indicators to better protect against viral waterborne outbreaks. This study aimed to detect and determine correlation between coliphages (F-specific and somatic), fecal indicator bacteria (enterococci and fecal coliforms), and human enteric viruses (human adenovirus) in a subtropical brackish estuarine lake. Water samples were collected from 9 estuarine recreation sites on Lake Pontchartrain in southeast Louisiana. Water samples (n = 222, collected weekly) were analyzed for coliphages and fecal indicator bacteria using culture-based methods and large volume water samples (n = 54, collected monthly) were analyzed for human adenovirus using quantitative PCR. Somatic coliphage and F-specific coliphage were found in 93.7 and 65.2% of samples with geometric mean concentrations of 30 and 3 plaque forming units (PFU) per 100 mL, respectively. Enterococci, fecal coliforms, and adenovirus were found in all samples with geometric mean concentrations of 27 most probable number (MPN), 77 MPN, and 3.0 × 10⁴ gene copies per 100 mL, respectively. Watersheds in suburban areas exhibited significantly higher concentrations of coliphages and fecal indicator bacteria, indicating potential fecal contamination from septic systems. There was no significant correlation (p > 0.05) observed between the presence of adenoviruses and fecal indicator bacteria and coliphages. The presence of human adenovirus in Lake Pontchartrain poses a significant public health problem for both recreational use and seafood harvesting as it increases exposure risks. This study demonstrated the lack of relationship between fecal indicators and human viral pathogen in Lake Pontchartrain supporting an alternative microbial surveillance system such as direct pathogen detection.

Survival of E. coli O157:H7, Salmonella Typhimurium, HAdV2 and MNV-1 in river water under dark conditions and varying storage temperatures

The ability of Escherichia coli O157:H7, Salmonella enterica serovar Typhimurium, Human adenovirus serotype 2 (HAdV2) and Murine Norovirus 1 (MNV-1) to survive in river water at -20, 4, room temperature (~24 °C) and 37 °C, were evaluated under dark conditions. The tested surface water was obtained from the main Nile River in the Dokki area, Giza and sterilized by autoclaving. The pathogens were inoculated separately in the autoclaved river water. Each microcosm was sampled and the test microorganisms counted after zero (immediately following inoculation), 1, 7, 15, 30, 60, 90 and 120 days. Physicochemical parameters including pH, turbidity, electrical conductivity, dissolved oxygen, total dissolved solids, total alkalinity, biological oxygen demand, chemical oxygen demand, nitrates and nitrites, and sulphate, were also measured. For HAdV2, the highest decay rates were observed at 37 °C and room temperature compared to 4 and -20 °C. A similar trend was found for the MNV-1, although unlike the HAdV2, the decay rate was higher at -20 than at 4 °C. Also, 4 °C was the best temperature for the survival of MNV-1 (T₉₀ = 76.9 days), E. coli O157:H7 (T₉₀ = 103 days) and Salmonella Typhimurium (T₉₀ = 105 days). The least survival of the pathogens, except MNV-1, was recorded at 37 °C. These results indicate that under dark conditions and low temperatures, enteric pathogens could be stable for extended periods. No significant statistical correlation was observed between the experimental temperatures and the infectivity of the viral particles. This study provided useful information about the stability of these pathogens in the Nile River water and could serve as an early warning when considering the water of the river for agricultural irrigation or household use in areas with limited or no access to potable water.

Relationships between Microbial Indicators and Pathogens in Recreational Water Settings

Fecal pollution of recreational waters can cause scenic blight and pose a threat to public health, resulting in beach advisories and closures. Fecal indicator bacteria (total and fecal coliforms, Escherichia coli, and enterococci), and alternative indicators of fecal pollution (Clostridium perfringens and bacteriophages) are routinely used in the assessment of sanitary quality of recreational waters. However, fecal indicator bacteria (FIB), and alternative indicators are found in the gastrointestinal tract of humans, and many other animals and therefore are considered general indicators of fecal pollution. As such, there is room for improvement in terms of their use for informing risk assessment and remediation strategies. Microbial source tracking (MST) genetic markers are closely associated with animal hosts and are used to identify fecal pollution sources. In this review, we examine 73 papers generated over 40 years that reported the relationship between at least one indicator and one pathogen group or species. Nearly half of the reports did not include statistical analysis, while the remainder were almost equally split between those that observed statistically significant relationships and those that did not. Statistical significance was reported less frequently in marine and brackish waters compared to freshwater, and the number of statistically significant relationships was considerably higher in freshwater (p < 0.0001). Overall, significant relationships were more commonly reported between FIB and pathogenic bacteria or protozoa, compared to pathogenic viruses (p: 0.0022⁻0.0005), and this was more pronounced in freshwater compared to marine. Statistically significant relationships were typically noted following wet weather events and at sites known to be impacted by recent fecal pollution. Among the studies that reported frequency of detection, FIB were detected most consistently, followed by alternative indicators. MST markers and the three pathogen groups were detected least frequently. This trend was mirrored by reported concentrations for each group of organisms (FIB > alternative indicators > MST markers > pathogens). Thus, while FIB, alternative indicators, and MST markers continue to be suitable indicators of fecal pollution, their relationship with waterborne pathogens, particularly viruses, is tenuous at best and influenced by many different factors such as frequency of detection, variable shedding rates, differential fate and transport characteristics, as well as a broad range of site-specific factors such as the potential for the presence of a complex mixture of multiple sources of fecal contamination and pathogens.

Comprehensive Study on Enteric Viruses and Indicators in Surface Water in Kyoto, Japan, During 2014-2015 Season

Certain enteric viruses that are present in the water environment are potential risk factors of waterborne infections. To better understand the impact of viruses in water, both enteric viruses and their potential indicators should be comparatively investigated. In this study, occurrences of GI- and GII-noroviruses (NoVs), sapovirus (SaV), rotavirus (RoV), Aichi virus 1 (AiV-1), enterovirus (EV), and pepper mild mottle virus (PMMoV) were quantitatively determined in surface water samples in Japan. Additionally, the genotype distribution of GI- and GII-NoVs was determined using a next-generation amplicon sequencing. PMMoV was the most abundant virus regardless of season and location, indicating its usefulness as an indicator for the viral contamination of water. Other potential indicators, AiV and EV, were less abundant than GII-NoV. Viruses other than PMMoV showed seasonality, i.e., EV and other viruses (NoVs, SaV, RoV, and AiV-1) became prevalent during summer and winter, respectively. SaV showed a relatively high abundance at a location that was affected by untreated wastewater. Regarding NoV genotypes, GI.1, GI.2, GI.4, GI.5, GI.6, GII.3, GII.4, GII.6, and GII.17 were found from the surface water samples. GII.4 and GII.17 seemed to have contributed to the high abundance of GII-NoV in the samples. Interestingly, GII.17 strains became prevalent in the water samples before becoming prevalent among gastroenteritis patients in Japan. These findings provide further insights into the properties of viruses as contaminants in the water environment.

Viral tools for detection of fecal contamination and microbial source tracking in wastewater from food industries and domestic sewage

Alternative indicators may be more suitable than thermotolerant coliform bacteria to assess enteric virus pollution in environmental waters and their removal from wastewaters. In this study, F-specific RNA bacteriophages (F-RNAPh) showed to be potential viral indicators of fecal contamination when they were quantified from domestic and food-industrial effluents containing human, chicken, swine or bovine wastes. In addition, they showed to be resistant to the primary and secondary treatments of the wastewater treatment plants. The viable F-RNAPh count showed correlation with viable thermotolerant coliforms but also with human polyomaviruses (HPyV) quantified by a new molecular method. In domestic effluents, F-RNAPh and HPyV indicators significantly correlated with a human viral pathogen, norovirus, while the bacterial indicator did not, being then better predictors of the behavior of enteric pathogenic viruses. In addition, we assessed human, bovine and fowl microbial source tracking markers, based on the molecular detections of human polyomavirus, bovine polyomavirus, and fowl adenovirus, respectively. The techniques implemented extend the range of viruses detected, since they target different viral types simultaneously. These markers could be applied when multiple source pollution is suspected, contributing to making decisions on public health interventions.

A review on recent progress in the detection methods and prevalence of human enteric viruses in water

Waterborne human enteric viruses, such as noroviruses and adenoviruses, are excreted in the feces of infected individuals and transmitted via the fecal-oral route including contaminated food and water. Since viruses are normally present at low concentrations in aquatic environments, they should be concentrated into smaller volumes prior to downstream molecular biological applications, such as quantitative polymerase chain reaction (qPCR). This review describes recent progress made in the development of concentration and detection methods of human enteric viruses in water, and discusses their applications for providing a better understanding of the prevalence of the viruses in various types of water worldwide. Maximum concentrations of human enteric viruses in water that have been reported in previous studies are summarized to assess viral abundances in aquatic environments. Some descriptions are also available on recent applications of sequencing analyses used to determine the genetic diversity of viral genomes in water samples, including those of novel viruses. Furthermore, the importance and significance of utilizing appropriate process controls during viral analyses are discussed, and three types of process controls are considered: whole process controls, molecular process controls, and (reverse transcription (RT)-)qPCR controls. Although no standards have been established for acceptable values of virus recovery and/or extraction-(RT-)qPCR efficiency, use of at least one of these appropriate control types is highly recommended for more accurate interpretation of observed data.

Coliphages and Gastrointestinal Illness in Recreational Waters: Pooled Analysis of Six Coastal Beach Cohorts

BACKGROUND

Coliphages have been proposed as indicators of fecal contamination in recreational waters because they better mimic the persistence of pathogenic viruses in the environment and wastewater treatment than fecal indicator bacteria. We estimated the association between coliphages and gastrointestinal illness and compared it with the association with culturable enterococci.

METHODS

We pooled data from six prospective cohort studies that enrolled coastal beachgoers in California, Alabama, and Rhode Island. Water samples were collected and gastrointestinal illness within 10 days of the beach visit was recorded. Samples were tested for enterococci and male-specific and somatic coliphages. We estimated cumulative incidence ratios (CIR) for the association between swimming in water with detectable coliphage and gastrointestinal illness when human fecal pollution was likely present, not likely present, and under all conditions combined. The reference group was unexposed swimmers. We defined continuous and threshold-based exposures (coliphage present/absent, enterococci >35 vs. ≤35 CFU/100 ml).

RESULTS

Under all conditions combined, there was no association between gastrointestinal illness and swimming in water with detectable coliphage or enterococci. When human fecal pollution was likely present, coliphage and enterococci were associated with increased gastrointestinal illness, and there was an association between male-specific coliphage level and illness that was somewhat stronger than the association between enterococci and illness. There were no substantial differences between male-specific and somatic coliphage.

CONCLUSIONS

Somatic coliphage and enterococci had similar associations with gastrointestinal illness; there was some evidence that male-specific coliphage had a stronger association with illness than enterococci in marine waters with human fecal contamination.

Evaluation of the dry and wet weather recreational health risks in a semi-enclosed marine embayment in Southern California

For many coastal regions around the world, recreational beach water quality is assessed using fecal indicator bacteria (FIB). However, the utility of FIB as indicators of recreational water illness (RWI) risk has been questioned, particularly in coastal settings with no obvious sources of human sewage. In this study we employed a source-apportionment quantitative microbial risk assessment (SA-QMRA) to assess RWI risk at a popular semi-enclosed recreational beach in Southern California (Baby Beach, City of Dana Point) with no obvious point sources of human sewage. Our SA-QMRA results suggest that, during dry weather, the median RWI risk at this beach is below the U.S. EPA recreational water quality criteria (RWQC) of 36 illness cases per 1000 bathers. During wet weather, the median RWI risk predicted by SA-QMRA depends on the assumed level of human waste associated with stormwater; the RWI risk is below the EPA RWQC illness risk benchmark 100% of the time provided that <2% of the FIB in stormwater are of human origin. However, these QMRA outcomes contrast strongly with the EPA RWQC for 30-day geometric mean of enterococci bacteria. Our results suggest that SA-QMRA is a useful framework for estimating robust RWI risk that takes into account local information about possible human and non-human sources of FIB.

Quantitative PCR Detection and Characterisation of Human Adenovirus, Rotavirus and Hepatitis A Virus in Discharged Effluents of Two Wastewater Treatment Facilities in the Eastern Cape, South Africa

The occurrence of enteric viruses in reclaimed wastewater, their removal by efficient treatment processes and the public health hazards associated with their release into the environments are of great significance in environmental microbiology. In this study, TaqMan-based real-time polymerase chain reaction (qPCR) was used to assess the prevalence of human adenovirus (HAdV), rotavirus (RV) and hepatitis A virus (HAV) in the final effluents of two wastewater treatment plants in the Eastern Cape Province, South Africa, over a twelve-month sampling period. The correlation between the concentrations of viruses in the effluents samples and faecal coliform (FC) densities were assessed as to validate the use of FC as microbiological indicator in water quality assessment. HAdV was detected in 62.5 % (30/48) of the samples with concentrations ranging between 8.4 × 101 and 1.0 × 105 genome copies/L while HAV and RV were only detected at concentrations below the set detection limits. FCs densities ranged from 1 to 2.7 × 104 CFU/100 ml. Adenovirus species HAdV-B (serotype 2) and HAdV-F (serotype 41) were detected in 86.7 % (26/30) and 6.7 % (2/30) of the HAdV-positive samples, respectively. No consistent seasonal trend was observed in HAdV concentrations, however, increased concentrations of HAdV were generally observed in the winter months. Also, there was no correlation between the occurrence of HAdV and FC at both the treatment plants. The persistent occurrence of HAdV in the discharged treated effluents points to the potential public health risk through the release of HAdV into the receiving watersheds, and the possibility of their transmission to human population.

Applying QMRA and DALY to assess health risks from river bathing

To estimate the health impact of bathing in urban river waters a two-step risk assessment was conducted using the example of the Ruhr River in North-Rhine Westphalia (Germany). The risk of acquiring gastrointestinal illness (GI) due to bathing in the Ruhr River was the focus of this analysis. Referring to the WHO guidelines for safe recreational water environments, risk was defined as the probability of occurrence x severity of harm. Thus, the probability of acquiring GI by bathing in the Ruhr River has been calculated by means of the quantitative microbial risk assessment (QMRA) method. Additionally to this, harm was operationalized by using the DALY metric, quantifying the impact of disability for public health. The calculation of the DALYs based on the QMRA results, disease and lethality data of the population, duration of diseases, disability weights and a demographic profile of a regionally determined potential bathing population. DALYs were calculated for norovirus gastroenteritis, rotavirus gastroenteritis, cryptosporidiosis and giardiasis. The calculated DALYs were set into relation to other risks of daily life. Furthermore the effect of age weighting and time discounting for this site-specific population was considered. The viral load caused the main part of the environmental burden of disease by bathing in the river. The calculated DALYs are significantly lower than DALYs for all cause GI in Germany, which reach 1.19 DALY/1000, or DALYs accepted for an official EG designated bathing water (2.579 DALYs/1000 persons) but on a comparable level with the DALY for drowning (0.26 DALY/1000 Persons). The DALY concept provides a complementary tool to the QMRA for evaluating and comparing health risks arising from a specific environment for a specific population and behaviour and for comparing with other health risks of daily life.

Elimination of viruses from domestic wastewater: requirements and technologies

Domestic wastewater contains various pathogens, which, if not sufficiently eliminated, may enter the receiving water bodies and cause water-transmitted diseases. Among the waterborne pathogens, viruses may occur, survive and/or decay much differently from bacteria in water. In many cases, the diseases caused by viruses are more severe. Therefore, research efforts are mainly directed at the behavior of viruses in water environments, as well as the elimination of viruses from wastewater. In this paper, an overview of the occurrence of viruses in wastewater is presented, together with their categories, methods of detection and potential to cause waterborne diseases. As wastewater treatment plants are critical nodes for the influx and termination of virus transmission, the behavior of viruses at each stage of treatment is reviewed. Particular attention is paid to the unit operations, which play crucial roles in virus removals, such as coagulation and membrane filtration, and that for virus inactivation, such as chemical disinfection and UV irradiation. Future needs for the development of new technologies for virus elimination, source control, and finding more suitable indicators of viral pathogens are also highlighted.

Degradation and inactivation of adenovirus in water by photo-electro-oxidation

The present study analyzed the efficiency of the photo-electro-oxidation process as a method for degradation and inactivation of adenovirus in water. The experimental design employed a solution prepared from sterile water containing 5.107 genomic copies/L (gc/L) of a standard strain of human adenovirus type 5 (HAdV-5) divided into two equal parts, one to serve as control and one treated by photo-electro-oxidation (PEO) for 3 hours and with a 5A current. Samples collected throughout the exposure process were analyzed by real-time polymerase chain reaction (qPCR) for viral genome identification and quantitation. Prior to gene extraction, a parallel DNAse treatment step was carried out to assess the integrity of viral particles. Integrated cell culture (ICC) analyses assessed the viability of infection in a cell culture. The tested process proved effective for viral degradation, with a 7 log10 reduction in viral load after 60 minutes of treatment. The DNAse-treated samples exhibited complete reduction of viral load after a 75 minute exposure to the process, and ICC analyses showed completely non-viable viral particles at 30 minutes of treatment.

Bioaccumulation of animal adenoviruses in the pink shrimp

Adenoviruses are among the most promising viral markers of fecal contamination. They are frequently found in the water, sediment and soil of regions impacted by human activity. Studies of the bioaccumulation of enteric viruses in shrimp are scarce. The cities located in the northern coast of the lake systems in Southern Brazil have high urbanization and intensive farming rates, and poor sewage collection and treatment. One hundred (n = 100) Farfantepenaeus paulensis pink-shrimp specimens and 48 water samples were collected from coastal lagoons between June 2012 and May 2013. Water samples were concentrated and the shrimp, mashed. After DNA extraction, samples were analyzed by real time polymerase chain reaction (qPCR) in order to detect and quantify viral genomes. Thirty-five percent of shrimp samples were positive for contamination, predominantly by avian adenoviruses. A total of 91.7% of water samples contained adenoviruses DNA, with the human form being the most frequent. Our results provided evidence of significant bioaccumulation of adenoviruses in shrimp, showing the extent of the impact of fecal pollution on aquatic ecosystems.

Global occurrence of Torque teno virus in water systems

Bacterial indicator organisms are used globally to assess the microbiological safety of waters. However, waterborne viral outbreaks have occurred in drinking water systems despite negative bacterial results. Using viral markers may therefore provide more accurate health risk assessment data. In this study, fecal, wastewater, stormwater, surface water (fresh and salt), groundwater, and drinking water samples were analyzed for the presence or concentration of traditional indicators, innovative indicators and viral markers. Samples were obtained in the United States, Italy, and Australia and results compared to those reported for studies conducted in Asia and South America as well. Indicators included total coliforms, Escherichia coli, enterococci, male-specific coliphages, somatic coliphages and microviradae. Viral markers included adenovirus, polyomavirus, and a potential new surrogate, Torque teno virus (TTV). TTV was more frequently found in wastewaters (38-100%) and waters influenced by waste discharges (25%) than in surface waters used as drinking water sources (5%). TTV was also specific to human rather than animal feces. While TTV numbers were strongly correlated to other viral markers in wastewaters, suggesting its utility as a fecal contamination marker, data limitations and TTV presence in treated drinking waters demonstrates that additional research is needed on this potential viral indicator.

Assessment of public health risk associated with viral contamination in harvested urban stormwater for domestic applications

Capturing stormwater is becoming a new standard for sustainable urban stormwater management, which can be used to supplement water supply portfolios in water-stressed cities. The key advantage of harvesting stormwater is to use low impact development (LID) systems for treatment to meet water quality requirement for non-potable uses. However, the lack of scientific studies to validate the safety of such practice has limited its adoption. Microbial hazards in stormwater, especially human viruses, represent the primary public health threat. Using adenovirus and norovirus as target pathogens, we investigated the viral health risk associated with a generic scenario of urban stormwater harvesting practice and its application for three non-potable uses: 1) toilet flushing, 2) showering, and 3) food-crop irrigation. The Quantitative Microbial Risk Assessment (QMRA) results showed that food-crop irrigation has the highest annual viral infection risk (median range: 6.8×10(-4)-9.7×10(-1) per-person-per-year or pppy), followed by showering (3.6×10(-7)-4.3×10(-2)pppy), and toilet flushing (1.1×10(-7)-1.3×10(-4)pppy). Disease burden of each stormwater use was ranked in the same order as its viral infection risk: food-crop irrigation>showering>toilet flushing. The median and 95th percentile risk values of toilet-flushing using treated stormwater are below U.S. EPA annual risk benchmark of ≤10(-4)pppy, whereas the disease burdens of both toilet-flushing and showering are within the WHO recommended disease burdens of ≤10(-6)DALYspppy. However, the acceptability of showering risk interpreted based on the U.S. EPA and WHO benchmarks is in disagreement. These results confirm the safety of stormwater application in toilet flushing, but call for further research to fill the data gaps in risk modeling as well as risk benchmarks.

Evaluation of FRNA coliphages as indicators of human enteric viruses in a tropical urban freshwater catchment

This study aimed to evaluate the relationship between FRNA coliphages (FRNA GI to GIV) and human enteric viruses (human adenoviruses, HAdV, astroviruses, AstV, noroviruses, NoV, and rotaviruses, RoV) in a tropical urban freshwater catchment. Positive associations between human-specific coliphages and human viral pathogens substantiate their use as viral indicators and in microbial source tracking. Reverse transcription qPCR was used to measure the concentrations of viruses and FRNA coliphages in concentrated water samples. Environmental water samples were also analyzed for male-specific (F+) and somatic (Som) coliphages using plaque assay. The most abundant enteric virus was NoV (55%) followed by HAdV (33%), RoV (33%), and AstV (23%), while the most abundant FRNA genogroup was GI (85%) followed by GII (48%), GIV (8%) and GIII (7%). Concentrations of human-specific coliphages FRNA GII were positively correlated with NoV, HAdV, RoV, AstV, F+ and Som (τ = 0.5 to 0.3, P < 0.05) while concentrations of animal-specific coliphages FRNA GI were negatively correlated with HAdV and RoV (τ = -0.2, P < 0.05). This study demonstrates statistical relationships between human-specific coliphages and a suite of human enteric viruses in the environment.

Surveillance of enteric viruses and coliphages in a tropical urban catchment

An assessment of the occurrence and concentration of enteric viruses and coliphages was carried out in highly urbanized catchment waters in the tropical city-state of Singapore. Target enteric viruses in this study were noroviruses, adenoviruses, astroviruses and rotaviruses. In total, 65 water samples were collected from canals and the reservoir of the Marina catchment on a monthly basis over a period of a year. Quantitative PCR (qPCR) and single agar layer plaque assay (SAL) were used to enumerate target enteric viruses and coliphages in water samples, respectively. The most prevalent pathogen were noroviruses, detected in 37 samples (57%), particularly norovirus genogroup II (48%), with a mean concentration of 3.7 × 10(2) gene copies per liter. Rotavirus was the second most prevalent virus (40%) with a mean concentration of 2.5 × 10(2) GC/L. The mean concentrations of somatic and male-specific coliphages were 2.2 × 10(2) and 1.1 × 10(2) PFU/100 ml, respectively. The occurrence and concentration of each target virus and the ratio of somatic to male-specific coliphages varied at different sampling sites in the catchment. For sampling sites with higher frequency of occurrence and concentration of viruses, the ratio of somatic to male-specific coliphages was generally much lower than other sampling sites with lower incidences of enteric viruses. Overall, higher statistical correlation was observed between target enteric viruses than between enteric viruses and coliphages. However, male-specific coliphages were positively correlated with norovirus concentrations. A multi-level integrated surveillance system, which comprises the monitoring of bacterial indicators, coliphages and selected enteric viruses, could help to meet recreational and surface water quality criteria in a complex urbanized catchment.

Detecting Virus-Like Particles from the Umgeni River, South Africa

It is important to consider viruses in water quality because of their incidence as causal agents for diarrhoeal disease, and due to their characteristics, which allow them to survive in changing environmental conditions indefinitely. This study assessed the viral quality of the Umgeni River in South Africa seasonally. A two-step tangential flow filtration process was setup to remove the bacteria and to concentrate the virus populations from large volume water samples. The concentrated water samples contained up to 659 and 550 pfu/mL of somatic and F-RNA coliphages, respectively. Several virus families including Adenoviridae, Herpesviridae, Orthomyxoviridae, Picornaviridae, Poxviridae and Reoviridae were found in the river based on the morphologies examined under transmission electron microscopy. All concentrated water samples produced substantial cytopathic effects on the Vero, HEK 293, Hela and A549 cell lines. These results indicate the potential of viruses in the water samples especially from the lower catchment areas of the Umgeni River to infect human hosts throughout the year. The present study highlights the importance of routine environmental surveillance of human enteric viruses in water sources. This can contribute to a better understanding of the actual burden of disease on those who might be using the water directly without treatment.

HuBac and nifH source tracking markers display a relationship to land use but not rainfall

Identification of the source of fecal pollution is becoming a priority for states and territories in the U.S. in order to meet water quality standards and to develop and implement total maximum daily loads. The goal of this research was to relate microbial source tracking (MST) assay concentrations to land use and levels of impervious surfaces in order to gauge how increasing development is associated with human fecal contamination in inland watersheds. The concentrations of two proposed MST markers, targeting nifH of Methanobrevibacter smithii and HuBac of Bacteroides sp., were positively correlated with increasing anthropogenic development and impervious surfaces. Higher concentrations of these MST markers in more urbanized watersheds suggest that increasing development negatively affects water quality. Neither MST marker concentration was correlated with antecedent rainfall levels, and detection of markers did not differ between dry weather and rain events. Water samples were also analyzed for norovirus and enterovirus, but these enteric viruses were rarely detected. These MST results differ from previous studies that have found correlations between traditional fecal indicator bacteria (FIB) and antecedent rainfall. This difference suggests that the MST markers used in this study may be more specific for recent, land-based contamination events as opposed to resuspension of particle-associated organisms in waterways. HuBac was detected in 98% of samples, correlating with fecal coliform and Escherichia coli concentrations. The ubiquity of the HuBac marker in our samples suggests that this marker does not provide sufficiently different or additional information than FIB, and it is likely this marker was amplifying non-human targets. The nifH marker was detected in 30% of samples. Less than half of the nifH-positive samples contained levels of fecal coliforms or E. coli above regulatory thresholds, suggesting that nifH would be more useful when utilized simultaneously with FIB than in a tiered monitoring strategy. The results of this research suggests that land use factors play an important role in characterizing and mitigating fecal contamination in watersheds.

Escherichia coli in the Environment: Implications for Water Quality and Human Health

Escherichia coli is naturally present in the intestinal tracts of warm-blooded animals. Since E. coli is released into the environment through deposition of fecal material, this bacterium is widely used as an indicator of fecal contamination of waterways. Recently, research efforts have been directed towards the identification of potential sources of fecal contamination impacting waterways and beaches. This is often referred to as microbial source tracking. However, recent studies have reported that E. coli can become "naturalized" to soil, sand, sediments, and algae in tropical, subtropical, and temperate environments. This phenomenon raises issues concerning the continued use of this bacterium as an indicator of fecal contamination. In this review, we discuss the relationship between E. coli and fecal pollution and the use of this bacterium as an indicator of fecal contamination in freshwater systems. We also discuss recent studies showing that E. coli can become an active member of natural microbial communities in the environment, and how this bacterium is being used for microbial source tracking. We also discuss the impact of environmentally-"naturalized" E. coli populations on water quality.

Application of enteric viruses for fecal pollution source tracking in environmental waters

Microbial source tracking (MST) tools are used to identify sources of fecal pollution for accurately assessing public health risk and implementing best management practices (BMPs). This review focuses on the potential of enteric viruses for MST applications. Following host infection, enteric viruses replicate and are excreted in high numbers in the hosts' feces and urine. Due to the specificity in host infection, enteric viruses have been considered one of the most accurate library-independent culture-independent MST tools. In an assessment of molecular viral assays based on sensitivity, specificity and the density of the target virus in fecal-impacted samples, human adenovirus and human polyomavirus were found to be the most promising human-specific viral markers. However, more research is needed to identify promising viral markers for livestock because of cross-reactions that were observed among livestock species or the limited number of samples tested for specificity. Other viral indicators of fecal origin, F+ RNA coliphage and pepper mild mottle virus, have also been proposed as potential targets for developing MST markers. Enhancing the utility of enteric viruses for MST applications through next generation sequencing (NGS) and virus concentration technology is discussed in the latter part of this review. The massive sequence databases generated by shotgun and gene-targeted metagenomics enable more efficient and reliable design of MST assays. Finally, recent studies revealed that alternative virus concentration methodologies may be more cost-effective than standard technologies such as 1MDS; however, improvements in the recovery efficiency and consistency are still needed. Overall, developments in metagenomic information combined with efficient concentration methodologies, as well as high host-specificity, make enteric viruses a promising tool in MST applications.

Detection and molecular characterization of human noroviruses in Korean groundwater between 2008 and 2010

RT-PCR, nucleotide sequencing, and phylogenetic analysis were performed for genotyping and molecular characterization of noroviruses isolated from Korean groundwater. Among 160 samples collected from 80 sites between 2008 and 2010, 14 samples (8.7 %) from 12 sites were positive for noroviruses (NoVs). The percentages of NoV-positive samples in 2008, 2009, and 2010 were 22.2, 3.2, and 0 %, respectively, representing a yearly decrease. GII-positive samples (n = 9, 5.6 %) outnumbered GI-positive samples (n = 5, 3.1 %). The genotypes of the GI NoVs were GI.2, GI.5, and GI.6, and the genotypes of the GII NoVs were all GII.4. One sample, HM623465, was very similar to CUK-3 and CBNU2 and two GII.4 sequences isolated from the stool of Korean gastroenteritis patients. A BLASTN search revealed several nucleotide sequences highly similar to those of NoVs isolated in this study. The original isolation sources for these similar NoVs were mostly stool (n = 731, 80.0 %) and groundwater (n = 135, 14.8 %), and all the countries from which they were isolated were almost in Asia (96.0 %); specifically, China (n = 192, 21.0 %), Japan (n = 383, 41.9 %), Korea (n = 296, 32.4 %), and other Asian countries (n = 6, 0.7 %). These results suggest that Korean groundwater might be contaminated with NoVs from the stool of infected patients and that these NoVs in turn cause new cases of gastroenteritis through a typical fecal-oral route with region-specific circulation. Therefore, it is important to properly treat sewage, which may include waterborne viruses and manage point sources in groundwater for national health and sanitation. In addition, continuous molecular surveillance remains important for understanding circulating NoVs.

Microbiological and physicochemical analysis of the coastal waters of southern Brazil

The aim of this study was to assess the impact of sewage discharge on coastal waters by evaluating the influence of physicochemical parameters on the presence of enteric microorganisms in seawater samples collected from 11 beaches in Florianopolis, Santa Catarina, Brazil, over a one-year period (August 2009 to July 2010). Samples were assessed for the presence of human adenoviruses (HAdV), polyomavirus (JCPyV), hepatitis A virus (HAV), and noroviruses (HuNoV GI and GII). Escherichia coli and physicochemical parameters (salinity, temperature, pH and dissolved oxygen) were also evaluated. From the 132 samples analyzed, 55% were positive for HAdV, 51.5% for HAV, 7.5% for HuNoV GI, 4.5% for HuNoV GII, and 3% for JCPyV. E. coli levels ranged from 8 to 1325 CFU/100mL at all sites. The overall results highlight the problem of sewage discharge into coastal waters and confirm that there is no correlation between viral presence and bacterial contamination.

Rapid quantification of infectious enterovirus from surface water in Bohai Bay, China using an integrated cell culture-qPCR assay

To rapidly quantify infectious enteroviruses polluting the coastal seawaters, a newly developed integrated cell culture and reverse transcription quantitative PCR (ICC-RT-qPCR) assay was used to identify the contamination by enteroviruses in winter seawater samples of Bohai Bay, Tianjin, China. The gene copies of enteroviral 5'UTRs correlated to the initial inoculum numbers across the concentration range of 0.05-500 PFU mL(-1) (correlation coefficient (R(2)) was 0.9667). ICC-qPCR revealed that five of seven samples (70.4%) were positive for infectious enteroviruses. The concentration of enteroviruses was estimated at 0.2-21 PFU L(-1). The result demonstrated that the contamination of enteroviruses in this coastal area may constitute a potential public health risk. This study established a practical assay for widespread monitoring studies of aquatic environments for viral contamination and provided meaningful data for human waterborne viral risk assessment.

Investigation of norovirus occurrence in groundwater in metropolitan Seoul, Korea

Groundwater is an important source of drinking and household water worldwide. Hence, the quality of groundwater is very important for preventing waterborne disease outbreaks and should be properly monitored. This study investigated the prevalence of waterborne viruses and fecal indicators in groundwater in metropolitan Seoul and Gyeonggi province, South Korea. A total of 116 samples of groundwater were taken using NanoCeram filters during both summer (June to August) and fall-winter seasons (October to December) in 2008. Among 71 sampling sites, 28 (48.3%) and 18 (35.3%) were positive for norovirus (NoV) from the summer and fall-winter season, respectively. The identified genotypes of NoV include GI-1, 4, 8, 9 and GII-4, 10, 11 (or 17), 13, 15 (or 16). None of fecal indicators was significantly correlated with NoV in groundwater. Among the tested fecal indicators, somatic coliphage (95.3%) showed an excellent true-negative rate of NoV occurrence. The combination of chemical, microbial and viral indicators increased the positive predictive value (50-100%). This study demonstrated a high prevalence of NoV in groundwater in metropolitan Seoul areas and characterized the positive and negative predictive values of a fecal indicator for predicting NoV prevalence.

Indicator microbes correlate with pathogenic bacteria, yeasts and helminthes in sand at a subtropical recreational beach site

AIMS

Research into the relationship between pathogens, faecal indicator microbes and environmental factors in beach sand has been limited, yet vital to the understanding of the microbial relationship between sand and the water column and to the improvement of criteria for better human health protection at beaches. The objectives of this study were to evaluate the presence and distribution of pathogens in various zones of beach sand (subtidal, intertidal and supratidal) and to assess their relationship with environmental parameters and indicator microbes at a non-point source subtropical marine beach.

METHODS AND RESULTS

In this exploratory study in subtropical Miami (Florida, USA), beach sand samples were collected and analysed over the course of 6 days for several pathogens, microbial source tracking markers and indicator microbes. An inverse correlation between moisture content and most indicator microbes was found. Significant associations were identified between some indicator microbes and pathogens (such as nematode larvae and yeasts in the genus Candida), which are from classes of microbes that are rarely evaluated in the context of recreational beach use.

CONCLUSIONS

Results indicate that indicator microbes may predict the presence of some of the pathogens, in particular helminthes, yeasts and the bacterial pathogen Staphylococcus aureus including methicillin-resistant forms. Indicator microbes may thus be useful for monitoring beach sand and water quality at non-point source beaches.

SIGNIFICANCE AND IMPACT OF THE STUDY

The presence of both indicator microbes and pathogens in beach sand provides one possible explanation for human health effects reported at non-point sources beaches.

Microbial water quality of the Georgian coastal zone of the Black Sea

From 2006 to 2008, microbial water quality was monitored along the Georgian coast of the Black Sea. Temperature, pH, salinity, and dissolved oxygen were measured, along with a variety of aquatic microbial parameters, including heterotrophic plate count (HPC), total culturable bacterial count (TCBC), and chlorophyll a (Chl-a) concentration. Total and fecal coliforms and total enterococci counts were recorded as indicators of fecal pollution. Vibrio bacteria, and Escherichia coli- and Vibrio-specific bacteriophages were isolated and enumerated to determine their relationships to standard marine pollution indicators. Persistent microbial pollution was observed, particularly in the summer months, with a higher rate of contamination in estuaries. Microbial indicators generally showed seasonal dependence, suggesting that temperature may influence bacterial dynamics in this environment. No correlation was apparent between fecal pollution indicators and physical-chemical and aquatic microbial parameters, although there were significant relationships amongst the indicators themselves, as well as with the prevalence of Vibrio bacteria and phage.

Ecology of coliphages in southern California coastal waters

AIMS

This study aims to investigate the ecology of coliphages, an important microbial pollution indicator. Specifically, our experiments address (i) the ability of environmental Escherichia coli (E. coli) to serve as hosts for coliphage replication, and (ii) the temporal and spatial distribution of coliphages in coastal waters.

METHODS AND RESULTS

Water samples from three locations in California's Newport Bay watershed were tested for the presence of coliphages every 2 weeks for an entire year. A total of nine E. coli strains isolated from various sources served as hosts for coliphage detection. Coliphage occurrence was significantly different between freshwater, estuarine and coastal locations and correlated with water temperature, salinity and rainfall in the watershed. The coliphages isolated on the environmental hosts had a broad host-range relative to the coliphages isolated on an E. coli strain from sewage and a US EPA recommended strain for coliphage detection.

CONCLUSIONS

Coliphage occurrence was related to the temperature, rainfall and salinity within the bay. The adaptation to a broad host-range may enable the proliferation of coliphages in the aquatic environment.

SIGNIFICANCE AND IMPACT OF THE STUDY

Understanding the seasonal variation of phages is useful for establishing a background level of coliphage presence in coastal waters. The broad host-range of coliphages isolated on the environmental E. coli host calls for investigation of coliphage replication in the aquatic environment.

Presence of pathogens and indicator microbes at a non-point source subtropical recreational marine beach

Swimming in ocean water, including ocean water at beaches not impacted by known point sources of pollution, is an increasing health concern. This study was an initial evaluation of the presence of indicator microbes and pathogens and the association among the indicator microbes, pathogens, and environmental conditions at a subtropical, recreational marine beach in south Florida impacted by non-point sources of pollution. Twelve water and eight sand samples were collected during four sampling events at high or low tide under elevated or reduced solar insolation conditions. The analyses performed included analyses of fecal indicator bacteria (FIB) (fecal coliforms, Escherichia coli, enterococci, and Clostridium perfringens), human-associated microbial source tracking (MST) markers (human polyomaviruses [HPyVs] and Enterococcus faecium esp gene), and pathogens (Vibrio vulnificus, Staphylococcus aureus, enterovirus, norovirus, hepatitis A virus, Cryptosporidium spp., and Giardia spp.). The enterococcus concentrations in water and sand determined by quantitative PCR were greater than the concentrations determined by membrane filtration measurement. The FIB concentrations in water were below the recreational water quality standards for three of the four sampling events, when pathogens and MST markers were also generally undetectable. The FIB levels exceeded regulatory guidelines during one event, and this was accompanied by detection of HPyVs and pathogens, including detection of the autochthonous bacterium V. vulnificus in sand and water, detection of the allochthonous protozoans Giardia spp. in water, and detection of Cryptosporidium spp. in sand samples. The elevated microbial levels were detected at high tide and under low-solar-insolation conditions. Additional sampling should be conducted to further explore the relationships between tidal and solar insolation conditions and between indicator microbes and pathogens in subtropical recreational marine waters impacted by non-point source pollution.

Covariation and photoinactivation of traditional and novel indicator organisms and human viruses at a sewage-impacted marine beach

Sunlight modulates concentrations of Escherichia coli and enterococci in marine waters. However, the mechanism of photoinactivation is poorly understood. Additionally, little is known about photoinactivation of other fecal indicators and human viruses in recreational waters. We sampled nearshore waters at Avalon Beach, California hourly for 72 h for reactive oxygen species (ROS), traditional indicator bacteria (E. coli and enterococci, and QPCR-based detection of enterococci), F+ (DNA and RNA) and somatic coliphages, the human-specific marker in Bacteroidales (HF marker), human enterovirus, and human adenovirus. E. coli and enterococci (regardless of measurement technique) covaried with each other and the coliphages suggesting similar sources and fates. The occurrence of the HF and enterovirus markers was correlated, but their occurrence was not positively correlated with the other indicators. Lower concentrations or occurrence of all microbes, excluding the HF and enterovirus markers, were observed during sunlit as opposed to dark hours, pointing to the importance of photoinactivation. Empirical-deterministic models for a subset of microbial indicators were created to determine field-relevant sunlight inactivation rates while accounting for time dependent sources and sinks. Photoinactivation rates of enterococci and E. coli, enterococci measured by QPCR, and somatic coliphage were estimated at 7, 6, 3, and 28 d(-1) I(-1), respectively, where I is UVB intensity in W/m(2). Average H(2)O(2) was 183 nM and the maximum singlet oxygen steady state concentration was 6.6 fM. Given the clarity of the water, direct genomic damage of bacteria and coliphage, as well as indirect endogenous damage of bacteria, were likely the most important inactivation mechanisms, but we cannot rule out a contribution by indirect mechanisms involving the H(2)O(2) and singlet oxygen produced exogenously.

Pepper mild mottle virus as an indicator of fecal pollution

Accurate indicators of fecal pollution are needed in order to minimize public health risks associated with wastewater contamination in recreational waters. However, the bacterial indicators currently used for monitoring water quality do not correlate with the presence of pathogens. Here we demonstrate that the plant pathogen Pepper mild mottle virus (PMMoV) is widespread and abundant in wastewater from the United States, suggesting the utility of this virus as an indicator of human fecal pollution. Quantitative PCR was used to determine the abundance of PMMoV in raw sewage, treated wastewater, seawater exposed to wastewater, and fecal samples and/or intestinal homogenates from a wide variety of animals. PMMoV was present in all wastewater samples at concentrations greater than 1 million copies per milliliter of raw sewage. Despite the ubiquity of PMMoV in human feces, this virus was not detected in the majority of animal fecal samples tested, with the exception of chicken and seagull samples. PMMoV was detected in four out of six seawater samples collected near point sources of secondary treated wastewater off southeastern Florida, where it co-occurred with several other pathogens and indicators of fecal pollution. Since PMMoV was not found in nonpolluted seawater samples and could be detected in surface seawater for approximately 1 week after its initial introduction, the presence of PMMoV in the marine environment reflects a recent contamination event. Together, these data demonstrate that PMMoV is a promising new indicator of fecal pollution in coastal environments.

Pepper mild mottle virus as an indicator of fecal pollution

Accurate indicators of fecal pollution are needed in order to minimize public health risks associated with wastewater contamination in recreational waters. However, the bacterial indicators currently used for monitoring water quality do not correlate with the presence of pathogens. Here we demonstrate that the plant pathogen Pepper mild mottle virus (PMMoV) is widespread and abundant in wastewater from the United States, suggesting the utility of this virus as an indicator of human fecal pollution. Quantitative PCR was used to determine the abundance of PMMoV in raw sewage, treated wastewater, seawater exposed to wastewater, and fecal samples and/or intestinal homogenates from a wide variety of animals. PMMoV was present in all wastewater samples at concentrations greater than 1 million copies per milliliter of raw sewage. Despite the ubiquity of PMMoV in human feces, this virus was not detected in the majority of animal fecal samples tested, with the exception of chicken and seagull samples. PMMoV was detected in four out of six seawater samples collected near point sources of secondary treated wastewater off southeastern Florida, where it co-occurred with several other pathogens and indicators of fecal pollution. Since PMMoV was not found in nonpolluted seawater samples and could be detected in surface seawater for approximately 1 week after its initial introduction, the presence of PMMoV in the marine environment reflects a recent contamination event. Together, these data demonstrate that PMMoV is a promising new indicator of fecal pollution in coastal environments.

Quantification of human polyomaviruses JC Virus and BK Virus by TaqMan quantitative PCR and comparison to other water quality indicators in water and fecal samples

In the United States, total maximum daily load standards for bodies of water that do not meet bacterial water quality standards are set by each state. The presence of human polyomaviruses (HPyVs) can be used as an indicator of human-associated sewage pollution in these waters. We have developed and optimized a TaqMan quantitative PCR (QPCR) assay based on the conserved T antigen to both quantify and simultaneously detect two HPyVs; JC virus and BK virus. The QPCR assay was able to consistently quantify > or =10 gene copies per reaction and is linear over 5 orders of magnitude. HPyVs were consistently detected in human waste samples (57 of 64) and environmental waters with known human fecal contamination (5 of 5) and were not amplified in DNA extracted from 127 animal waste samples from 14 species. HPyV concentrations in sewage decreased 81.2 and 84.2% over 28 days incubation at 25 and 35 degrees C, respectively. HPyVs results were compared to Escherichia coli, fecal coliform, and enterococci concentrations and the presence of three other human-associated microbes: Bacteroidetes, Methanobrevibacter smithii, and adenovirus. HPyVs were the most frequently detected of these in human and contaminated environmental samples and were more human specific than the Bacteroidetes (HF183) or M. smithii. HPyVs and M. smithii more closely mimicked the persistence of adenovirus in sewage than the other microbes. The use of this rapid and quantitative assay in water quality research could help regulatory agencies to identify sources of water pollution for improved remediation of contaminated waters and ultimately protect humans from exposure to pathogens.

Detection of adenoviruses and rotaviruses in drinking water sources used in rural areas of Benin, West Africa

Diseases associated with viruses also found in environmental samples cause major health problems in developing countries. Little is known about the frequency and pattern of viral contamination of drinking water sources in these resource-poor settings. We established a method to analyze 10 liters of water from drinking water sources in a rural area of Benin for the presence of adenoviruses and rotaviruses. Overall, 541 samples from 287 drinking water sources were tested. A total of 12.9% of the sources were positive for adenoviruses and 2.1% of the sources were positive for rotaviruses at least once. Due to the temporary nature of viral contamination in drinking water sources, the probability of virus detection increased with the number of samples taken at one test site over time. No seasonal pattern for viral contaminations was found after samples obtained during the dry and wet seasons were compared. Overall, 3 of 15 surface water samples (20%) and 35 of 247 wells (14.2%) but also 2 of 25 pumps (8%) tested positive for adenoviruses or rotaviruses. The presence of latrines within a radius of 50 m in the vicinity of pumps or wells was identified as being a risk factor for virus detection. In summary, viral contamination was correlated with the presence of latrines in the vicinity of drinking water sources, indicating the importance of appropriate decision support systems in these socioeconomic prospering regions.

Eukaryotic viruses in wastewater samples from the United States

Human fecal matter contains a large number of viruses, and current bacterial indicators used for monitoring water quality do not correlate with the presence of pathogenic viruses. Adenoviruses and enteroviruses have often been used to identify fecal pollution in the environment; however, other viruses shed in fecal matter may more accurately detect fecal pollution. The purpose of this study was to develop a baseline understanding of the types of viruses found in raw sewage. PCR was used to detect adenoviruses, enteroviruses, hepatitis B viruses, herpesviruses, morbilliviruses, noroviruses, papillomaviruses, picobirnaviruses, reoviruses, and rotaviruses in raw sewage collected throughout the United States. Adenoviruses and picobirnaviruses were detected in 100% of raw sewage samples and 25% and 33% of final effluent samples, respectively. Enteroviruses and noroviruses were detected in 75% and 58% of raw sewage samples, respectively, and both viral groups were found in 8% of final effluent samples. This study showed that adenoviruses, enteroviruses, noroviruses, and picobirnaviruses are widespread in raw sewage. Since adenoviruses and picobirnaviruses were detected in 100% of raw sewage samples, they are potential markers of fecal contamination. Additionally, this research uncovered previously unknown sequence diversity in human picobirnaviruses. This baseline understanding of viruses in raw sewage will enable educated decisions to be made regarding the use of different viruses in water quality assessments.