Gastroenteric Viruses Detection in a Drinking Water Distribution-to-Consumption System in a Low-Income Community in Rio de Janeiro.

The availability of drinking water is one of the main determinants of quality of life, disease prevention and the promotion of health. Viruses are important agents of waterborne diseases and have been described as important markers of human faecal contamination. This study aimed to investigate viruses' presence as an indicator of drinking water quality in low-income communities in the Manguinhos area, Rio de Janeiro, Brazil. Three hundred and four drinking water samples (2L/each) were collected along the drinking water distribution-to-consumption pathway in households, as well as healthcare and school units. Water samples were collected both directly from the water supply prior to distribution and after storage in tanks and filtration units. Using qPCR, viruses were detected 50 times in 45 water samples (15%), 19 of these being human adenovirus, 17 rotavirus A and 14 norovirus GII. Viral loads recovered ranged from 5E+10 to 8.7E+106 genome copies/Liter. Co-detection was observed in five household water samples and there was no difference regarding virus detection across sampling sites. Precarious and inadequate environmental conditions characterized by the lack of local infrastructure regarding basic sanitation and waste collection in the territory, as well as negligent hygiene habits, could explain viral detection in drinking water in regions with a water supply system.

Assessment of clinical signs associated with adenoviral epidemic keratoconjunctivitis cases in southern Japan between 2011 and 2014.

Adenoviral epidemic keratoconjunctivitis (EKC) is a major cause of ocular morbidity worldwide and specific antiviral therapies are not available. EKC is primarily caused by Human adenovirus D (HAdV-D) types 8, 37, 53, 54, 56 and 64. Considering the genomic variation in HAdV-D, we hypothesized that clinical signs could be differentiated by virus type. The hypothesis was retrospectively tested with clinical signs recorded from 250 patients with ocular infections visiting an ophthalmological clinic in southern Japan between 2011 and 2014. The results showed that conjunctival opacity, corneal epithelial disorders and pre-auricular lymphadenopathy, were more frequently associated with EKC than other ocular infections. Furthermore, HAdV types 8, 37 and 54, caused corneal complications and longer infections significantly more frequently than infections by types 53 and 56 (P < 0.05). Our descriptive results supported that symptoms severity vary with the infecting type, however, further research is needed to improve diagnosis of EKC.

Rapid assessment of viral water quality using a novel recombinase polymerase amplification test for human adenovirus.

Sensitive and rapid methods for determining viral contamination of water are critical, since illness can be caused by low numbers of viruses and bacterial indicators do not adequately predict viral loads. We developed novel rapid assays for detecting the viral water quality indicator human adenovirus (HAdV). A simple 15-min recombinase polymerase amplification step followed by a 5-min lateral flow detection is used. Species-specific assays were developed to discriminate HAdV A, B, C and F, and combined into a multiplex test (Ad-FAC). Species-specific assays enabled detection of 10-50 copies of the HAdV plasmid. Sample testing using methods optimised for wastewater analysis indicated the Ad-FAC assay showed 100% sensitivity and 100% specificity when compared with HAdV qPCR, with a detection limit as low as 50 gene copies. This is the first study to demonstrate the use of RPA for detecting enteric viruses in water samples, to assess virological water quality. The ability to rapidly detect enteric virus contamination of water could assist in more effective management of water safety and better protection of public health.

Occurrence of Human Enteric Adenoviruses in Fresh Tropical Seafood from Retail Markets and Landing Centers.

Human adenoviruses (HAdVs) are the foodborne enteric pathogens transmitted by the consumption of contaminated shellfish. In this study, the occurrence of enteric adenoviruses in finfish and shellfish was investigated by virus concentration and polymerase chain reaction (PCR). Total plate count, total coliform, and fecal coliform levels were determined and correlated with the presence of adenovirus. Samples of fish, bivalve mollusks, crustaceans, and cephalopods were collected from supermarkets, landing centers, and retail fish markets of Mumbai, India for the study. Overall, the adenovirus DNA was detected in 21.27% of all the samples analyzed. The highest incidence was detected in clams (14.89%), followed by oysters, shrimps, and finfish (2.13% each). High prevalence of enteric adenovirus in filter-feeding bivalves, such as clams and oysters, as well as in fish suggests persistent fecal contamination of coastal waters in the region of study. The occurrence of adenoviruses in samples showed a positive correlation with the bacteriological indicators of fecal contamination, suggesting that fecal indicator bacteria may be used to monitor the presence of adenoviruses in seafood. PRACTICAL APPLICATION: This research demonstrates the occurrence of human adenoviruse (HAdV) in fresh seafood and the utility of fecal coliforms as indicators of HAdV presence in seafood. The study emphasizes the need to identify HAdV in seafood as a human health hazard and implement measures to prevent sewage pollution of fish and shellfish harvesting areas in India.

Assessment of the Incidence of Human Adenovirus in Surface Waters of Southwest Greece: Vouraikos River as a Case Study.

The purpose of this study is to assess the overall impact of different anthropogenic activities in the Vouraikos River basin (southwestern Greece, Natura 2000 area). Virological quality of river water samples was investigated. Positive samples for human adenoviruses were found occasionally, while porcine adenoviruses and bovine polyoma viruses were not detected. It is the first time that virological data are collected in the study area.

Microbial risk assessment in recreational freshwaters from southern Brazil.

In this study, total coliforms (TC), Escherichia coli, enterovirus (EV), rotavirus (RV), and human mastadenovirus species C and F (HAdV-C and HAdV-F) were evaluated in water samples from Belo Stream. For HAdV-C and F, the infectivity was assessed by integrated cell culture quantitative real-time polymerase chain reaction (ICC-qPCR). Samples were collected monthly (May/2015 to April/2016) at four sites. Viral analyses were performed for both ultracentrifuge-concentrated and unconcentrated samples. For site P4 (used for recreational purposes), QMRA was applied to estimate health risks associated with exposure to E. coli and HAdV-C and F. TC and E. coli were present throughout the collection period. EV and RV were not detected. HAdV-C were present in 8.51% (1.89E + 06 to 2.28E + 07 GC (Genomic Copies)/L) and 21.27% (2.36E + 05 to 1.29E + 07 GC/L) for unconcentrated and concentrated samples, respectively. For HAdV-F were 12.76% (2.77E + 07 to 3.31E + 08 GC/L) and 48.93% (1.10E + 05 to 4.50E + 08 GC/L) for unconcentrated and concentrated samples, respectively. For unconcentrated samples, infectivity for HAdV-C was detected in 37.20% (1st ICC-qPCR) and 25.58% (2nd ICC-qPCR). For HAdV-F, infectivity was detected in 6.97% (1st ICC-qPCR) and 6.97% (2nd ICC-qPCR). For concentrated samples, HAdV-C infectious was observed in 17.02% (1st ICC-qPCR) and in 8.51% (2nd ICC-qPCR). For HAdV-F, were present in 8.51% for both 1st and 2nd ICC-qPCR. Statistical analyzes showed significant difference between the collection sites when analyzed the molecular data of HAdV-F, data of TC and E. coli. Correlation tests showed direct correlation between HAdV-F with E. coli and TC. E. coli concentrations translated to the lowest estimates of infection risks (8.58E-05 to 2.17E-03). HAdV-F concentrations were associated with the highest infection risks at 9.99E-01 and for group C, 1.29E-01 to 9.99E-01. These results show that commonly used bacterial indicators for water quality may not infer health risks associated with viruses in recreational freshwaters.

Human adenoviruses as waterborne index pathogens and their use for Quantitative Microbial Risk Assessment.

The current microbial water quality standards are based on the monitoring of fecal indicator organisms, which are mainly bacterial indicators (i.e., Escherichia coli, intestinal enterococci), however epidemiological data indicate that viruses are important etiological agents of waterborne illnesses. Among waterborne viruses, human adenovirus can be considered as an index pathogen, owing to its abundance in sewage and persistence in the environment, as well as its potential infectivity. In this study, data on human adenoviruses from different water matrices (the entrance and exit of a water treatment plant, rivers and seawaters) were analyzed, in parallel with traditional fecal bacterial indicators and somatic coliphages. The results showed a 64% frequency of positive adenovirus samples, decreasing from the sewage system (100% at the entrance and 94% at the exit) to rivers (92% and 72% for different rivers) and seawater (21%). Adenovirus concentrations showed a significant correlation with somatic coliphages in one river and seawater, thus supporting the recent inclusion of coliphages as viral indicators in water safety guidelines. The data collected were used to estimate adenovirus to indicator ratios, which could be used as input in Quantitative Microbial Risk Assessment (QMRA) studies.

Genotypic characterization and assessment of infectivity of human waterborne pathogens recovered from oysters and estuarine waters in Brazil.

Waterborne, food-borne and sewage-borne pathogens are a major global concern, with the annual recurrence, most notably during the summer, of outbreaks of gastroenteritis of unconfirmed etiology associated with recreational activities in marine environments. The consumption of contaminated water-based foodstuffs is also related to outbreaks of human illness. The main goals of the present study were: i) to identify the genetic assemblages of Giardia duodenalis cysts in growing and depurated oysters destined for human consumption on the southern coast of São Paulo, Brazil; ii) to verify the main circulating G. duodenalis assemblages and their subtypes in different brackish waters used for the production of mollusks and for recreational purposes; iii) to track the contamination of growing and depurated oysters by the human adenovirus and identify the infectivity of adenoviral particles recovered from oysters before and after depuration; iv) to evaluate the occurrence and genotype of the free-living amoebae of the genus Acanthamoeba in brackish water and oysters from all the sites described above. Four sampling sites in the Cananeia estuary were selected to search for pathogenic and amphizoic protozoa (Giardia and Acanthamoeba respectively): site 1: oyster growth, site 2: catchment water (before UV depuration procedure), site 3: filter backwash (filtration stage of water treatment) and site 4: oyster depuration tank. Oysters at sites 1 and 4 were evaluated for the presence of adenovirus (HAdV). Analysis consisted of conventional microbiological as well as molecular methods. Giardia duodenalis were detected in all the water sites analyzed and the molecular analysis revealed that sub-assemblage AII was the most frequently distributed throughout the estuarine environment, although one sample was identified as belonging to the assemblage C. Acanthamoeba were also isolated from different locations of the estuarine area, and were detected at all the analyzed sites. The majority of isolates belonged to the T3 genotype, while the T4 genotype was identified once. The sequencing reaction of Giardia duodenalis revealed the contamination of three batches of depurated oysters by the sub-assemblage AII. With respect to viruses, seven batches of oysters (four growing and three depurated) were found to be harboring infectious HAdV particles when submitted to plaque assay. Overall, the results of the sequencing reactions combined with the plaque assay revealed that the isolates of Giardia duodenalis and the infectious HAdV particles identified in oyster tissues have the potential to infect humans and pose a threat if consumed raw or lightly cooked. This is the first report on the sub-assemblage AII identified in oysters which are submitted to a cleaning and disinfection procedure prior to human consumption in Brazil. Acanthamoeba specific genotypes were also identified for the first time in a recreational estuarine area in Brazil, contributing to knowledge of their molecular and environmental epidemiology, which is considered scarce even in marine and estuarine areas of the world.

Evaluation of the suitability of a plant virus, pepper mild mottle virus, as a surrogate of human enteric viruses for assessment of the efficacy of coagulation-rapid sand filtration to remove those viruses.

Here, we evaluated the removal of three representative human enteric viruses - adenovirus (AdV) type 40, coxsackievirus (CV) B5, and hepatitis A virus (HAV) IB - and one surrogate of human caliciviruses - murine norovirus (MNV) type 1 - by coagulation-rapid sand filtration, using water samples from eight water sources for drinking water treatment plants in Japan. The removal ratios of a plant virus (pepper mild mottle virus; PMMoV) and two bacteriophages (MS2 and φX174) were compared with the removal ratios of human enteric viruses to assess the suitability of PMMoV, MS2, and φX174 as surrogates for human enteric viruses. The removal ratios of AdV, CV, HAV, and MNV, evaluated via the real-time polymerase chain reaction (PCR) method, were 0.8-2.5-log10 when commercially available polyaluminum chloride (PACl, basicity 1.5) and virgin silica sand were used as the coagulant and filter medium, respectively. The type of coagulant affected the virus removal efficiency, but the age of silica sand used in the rapid sand filtration did not. Coagulation-rapid sand filtration with non-sulfated, high-basicity PACls (basicity 2.1 or 2.5) removed viruses more efficiently than the other aluminum-based coagulants. The removal ratios of MS2 were sometimes higher than those of the three human enteric viruses and MNV, whereas the removal ratios of φX174 tended to be smaller than those of the three human enteric viruses and MNV. In contrast, the removal ratios of PMMoV were similar to and strongly correlated with those of the three human enteric viruses and MNV. Thus, PMMoV appears to be a suitable surrogate for human enteric viruses for the assessment of the efficacy of coagulation-rapid sand filtration to remove viruses.

Rapid Adenovirus typing method for species identification.

Adenoviruses are characterized by a large variability, reflected by their classification in species A to G. Certain species, eg A and C, could be associated with increased clinical severity, both in immunocompetent and immunocompromised hosts suggesting that in some instances species identification provides clinically relevant information. Here we designed a novel "pVI rapid typing method" to obtain quick, simple and cost effective species assignment for Adenoviruses, thanks to combined fusion temperature (Tm) and amplicon size analysis. Rapid typing results were compared to Sanger sequencing in the hexon gene for 140 Adenovirus-positive clinical samples included in the Typadeno study. Species A and C could be identified with a 100% positive predictive value, thus confirming the value of this simple typing method.

Virus recovering from strawberries: Evaluation of a skimmed milk organic flocculation method for assessment of microbiological contamination.

Skimmed milk organic flocculation method was adapted, optimized and compared with polyethylene glycol (PEG) precipitation and filtration methods for recovering viruses from a strawberry matrix. Spiking experiments with norovirus genogroup II genotype 4 (NoV GII.4) and murine norovirus 1 (MNV-1) demonstrated that the organic flocculation method associated with a glycine elution buffer, filter bag and cetyltrimethylammonium bromide (CTAB) showed a recovery percentage of 2.5 and 32 times higher than PEG precipitation and filtration methodologies for NoV recovering. Furthermore, this method was used for investigating NoV and human adenoviruses (HAdVs) in 90 samples of fresh strawberries commercialized in Rio de Janeiro markets. NoV GI and GII were not detected in those samples and MNV-1, used as internal process control (IPC), was recovered in 95.5% (86) of them. HAdVs were detected in 18 (20.0%) samples and characterized by nucleotide sequencing as Human Mastadenovirus specie F and as type specie HAdV-2. Bacterial analysis did not detect Salmonella spp. and Listeria monocytogenes, however, 3.3% of fecal coliforms were detected in those samples. These results indicate the organic flocculation method as an alternative for recovering enteric viruses from strawberries, emphasizing a need for virus surveillance in food matrices.

Quantitative farm-to-fork risk assessment model for norovirus and hepatitis A virus in European leafy green vegetable and berry fruit supply chains.

Fresh produce that is contaminated with viruses may lead to infection and viral gastroenteritis or hepatitis when consumed raw. It is thus important to reduce virus numbers on these foods. Prevention of virus contamination in fresh produce production and processing may be more effective than treatment, as sufficient virus removal or inactivation by post-harvest treatment requires high doses that may adversely affect food quality. To date knowledge of the contribution of various potential contamination routes is lacking. A risk assessment model was developed for human norovirus, hepatitis A virus and human adenovirus in raspberry and salad vegetable supply chains to quantify contributions of potential contamination sources to the contamination of produce at retail. These models were used to estimate public health risks. Model parameterization was based on monitoring data from European supply chains and literature data. No human pathogenic viruses were found in the soft fruit supply chains; human adenovirus (hAdV) was detected, which was additionally monitored as an indicator of fecal pollution to assess the contribution of potential contamination points. Estimated risks per serving of lettuce based on the models were 3×10(-4) (6×10(-6)-5×10(-3)) for NoV infection and 3×10(-8) (7×10(-10)-3×10(-6)) for hepatitis A jaundice. The contribution to virus contamination of hand-contact was larger as compared with the contribution of irrigation, the conveyor belt or the water used for produce rinsing. In conclusion, viral contamination in the lettuce and soft fruit supply chains occurred and estimated health risks were generally low. Nevertheless, the 97.5% upper limit for the estimated NoV contamination of lettuce suggested that infection risks up to 50% per serving might occur. Our study suggests that attention to full compliance for hand hygiene will improve fresh produce safety related to virus risks most as compared to the other examined sources, given the monitoring results. This effect will be further aided by compliance with other hygiene and water quality regulations in production and processing facilities.

Routine monitoring of adenovirus and norovirus within the health care environment.

This study investigated the presence of adenovirus and norovirus on ward surfaces using real-time polymerase chain reaction (PCR) to assist in the development of evidence-based infection control policy. Screening was carried out weekly for 6 months in the common areas of 2 pediatric wards. Additionally, a one-off screening was undertaken for adenovirus and norovirus on a day unit and for adenovirus only in patient cubicles while occupied. Over the 6-month screening of common areas, 2.4% of samples were positive for adenovirus or norovirus. In rooms occupied with adenovirus-infected children, all cubicle screening sites and almost all swabs were contaminated with adenovirus. In the day unit, 13% of samples were positive. Cleaning and environmental interaction strategies must therefore be designed to control nosocomial transmission of viruses outside of outbreak scenarios.

Integrating bacterial and viral water quality assessment to predict swimming-associated illness at a freshwater beach: a cohort study.

BACKGROUND & OBJECTIVE: Recreational waters impacted by fecal contamination have been linked to gastrointestinal illness in swimmer populations. To date, few epidemiologic studies examine the risk for swimming-related illnesses based upon simultaneous exposure to more than one microbial surrogate (e.g. culturable E. coli densities, genetic markers). We addressed this research gap by investigating the association between swimming-related illness frequency and water quality determined from multiple bacterial and viral genetic markers. METHODS: Viral and bacterial genetic marker densities were determined from beach water samples collected over 23 weekend days and were quantified using quantitative polymerase chain reaction (qPCR). These genetic marker data were paired with previously determined human exposure data gathered as part of a cohort study carried out among beach users at East Fork Lake in Ohio, USA in 2009. Using previously unavailable genetic marker data in logistic regression models, single- and multi-marker/multi-water quality indicator approaches for predicting swimming-related illness were evaluated for associations with swimming-associated gastrointestinal illness. RESULTS: Data pertaining to genetic marker exposure and 8- or 9-day health outcomes were available for a total of 600 healthy susceptible swimmers, and with this population we observed a significant positive association between human adenovirus (HAdV) exposure and diarrhea (odds ratio  = 1.6; 95% confidence interval: 1.1-2.3) as well as gastrointestinal illness (OR  = 1.5; 95% CI: 1.0-2.2) upon adjusting for culturable E. coli densities in multivariable models. No significant associations between bacterial genetic markers and swimming-associated illness were observed. CONCLUSIONS: This study provides evidence that a combined measure of recreational water quality that simultaneously considers both bacterial and viral densities, particularly HAdV, may improve prediction of disease risk than a measure of a single agent in a beach environment likely influenced by nonpoint source human fecal contamination.

Assessment of the risks for human health of adenoviruses, hepatitis A virus, rotaviruses and enteroviruses in the Buffalo River and three source water dams in the Eastern Cape.

Buffalo River is an important water resource in the Eastern Cape Province of South Africa. The potential risks of infection constituted by exposure to human enteric viruses in the Buffalo River and three source water dams along its course were assessed using mean values and static quantitative microbial risk assessment (QMRA). The daily risks of infection determined by the exponential model [for human adenovirus (HAdV) and enterovirus (EnV)] and the beta-Poisson model (for hepatitis A virus (HAV) and rotavirus (RoV)) varied with sites and exposure scenario. The estimated daily risks of infection values at the sites where the respective viruses were detected, ranged from 7.31 × 10(-3) to 1 (for HAdV), 4.23 × 10(-2) to 6.54 × 10(-1) (RoV), 2.32 × 10(-4) to 1.73 × 10(-1) (HAV) and 1.32 × 10(-4) to 5.70 × 10(-2) (EnV). The yearly risks of infection in individuals exposed to the river/dam water via drinking, recreational, domestic or irrigational activities were unacceptably high, exceeding the acceptable risk of 0.01% (10(-4) infection/person/year), and the guideline value used as by several nations for drinking water. The risks of illness and death from infection ranged from 6.58 × 10(-5) to 5.0 × 10(-1) and 6.58 × 10(-9) to 5.0 × 10(-5), respectively. The threats here are heightened by the high mortality rates for HAV, and its endemicity in South Africa. Therefore, we conclude that the Buffalo River and its source water dams are a public health hazard. The QMRA presented here is the first of its kinds in the Eastern Cape Province and provides the building block for a quantitatively oriented local guideline for water quality management in the Province.

A cost effective real-time PCR for the detection of adenovirus from viral swabs.

Compared to traditional testing strategies, nucleic acid amplification tests such as real-time PCR offer many advantages for the detection of human adenoviruses. However, commercial assays are expensive and cost prohibitive for many clinical laboratories. To overcome fiscal challenges, a cost effective strategy was developed using a combination of homogenization and heat treatment with an "in-house" real-time PCR. In 196 swabs submitted for adenovirus detection, this crude extraction method showed performance characteristics equivalent to viral DNA obtained from a commercial nucleic acid extraction. In addition, the in-house real-time PCR outperformed traditional testing strategies using virus culture, with sensitivities of 100% and 69.2%, respectively. Overall, the combination of homogenization and heat treatment with a sensitive in-house real-time PCR provides accurate results at a cost comparable to viral culture.

Assessment of human adenovirus removal by qPCR in an advanced water reclamation plant in Georgia, USA.

AIMS: To assess human adenoviruses (HAdVs) removal in an advanced wastewater treatment facility and compare two parallel tertiary treatment methods for the removal of HAdVs. METHODS AND RESULTS: Tangential flow ultrafiltration was used to concentrate the water samples, and HAdVs were precipitated by polyethylene glycol. HAdVs were detected only by TaqMan real-time PCR, and HAdV genotype was determined by DNA sequence. HAdVs were detected in 100% of primary clarification influent, secondary clarification effluent and granular media (GM) filtration effluent samples but only in 31·2% of membrane filtration (MF) effluent and 41·7% of final effluent (FE) samples, respectively. The average HAdVs loads were significantly reduced along the treatments but HAdVs were still present in FE. Comparison of two parallel treatments (GM vs MF) showed that MF was technically superior to GM for the removal of HAdVs. CONCLUSIONS: These findings indicate that adenoviruses are not completely removed by treatment processes. MF is a better treatment for removal of adenoviruses than GM filtration. Because only qPCR was used, the results only indicate the removal of adenovirus DNA and not the infectivity of viruses. SIGNIFICANCE AND IMPACT OF THE STUDY: Presence of HAdVs in FE by qPCR suggests a potential public health risk from exposure to the treated wastewater and using the FE for recreational or water reuse purposes should be cautious.

[Public health surveillance and assessment of emerging infectious threats: method and criteria for risk analysis]. / Veille sanitaire et appréciation du risque infectieux émergent: méthode et critères d'analyse du risque.

One of the objectives of the surveillance systems implemented by the French National Institute for Public Health Surveillance is to detect communicable diseases and to reduce their impact. For emerging infections, the detection and risk analysis pose specific challenges due to lack of documented criteria for the event. The surveillance systems detect a variety of events, or "signals" which represent a potential risk, such as a novel germ, a pathogen which may disseminate in a non-endemic area, or an abnormal number of cases for a well-known disease. These signals are first verified and analyzed, then classified as: potential public health threat, event to follow-up, or absence of threat. Through various examples, we illustrate the method and criteria which are used to analyze and classify these events considered to be emerging. The examples highlight the importance of host characteristics and exposure in groups at particular risk, such as professionals in veterinarian services, health care workers, travelers, immunodepressed patients, etc. The described method should allow us to identify future needs in terms of surveillance and to improve timeliness, quality of expertise, and feedback information regarding the public health risk posed by events which are insufficiently documented.

Assessment of human adenovirus removal in a full-scale membrane bioreactor treating municipal wastewater.

Human adenoviruses (HAdVs) in wastewater samples taken from four different treatment stages of a full-scale municipal wastewater treatment plant (i.e., incoming raw sewage, primary sedimentation effluent, membrane bioreactor (MBR) influent, and MBR effluent) were quantified by real-time PCR assays to further estimate removal efficiency of the HAdVs. Based on hexon gene sequence comparisons, HAdV species A, C, and F were consistently found in the wastewater samples. In general, all three identified HAdV species were detected in most of the wastewater samples using the real-time PCR assays. Overall HAdV concentrations were rather stable over the entire 8-month study period (January-August, 2008) (approximately 10(6)-10(7)viral particles/L of wastewater for the raw sewage and primary effluent; 10(8)-10(9)viral particles/L for the MBR influent; and, 10(3)-10(4)viral particles/L for the MBR effluent). No significant seasonal differences were noticed for the HAdV abundances. Removal efficiencies of the viral particles in the full-scale MBR process were assessed and showed an average HAdV removal of 5.0+/-0.6logs over the study period. The removal efficiencies for F species (average log removal of 6.5+/-1.3logs) were typically higher (p-value <0.05) than those of the other two species (average of 4.1+/-0.9 and 4.6+/-0.5logs for species A and C, respectively). These results demonstrate that the full-scale MBR system efficiently removed most HAdV from the wastewater leaving about 10(3)viral particles/L in the MBR effluent.

Assessment of the stability of human viruses and coliphage in groundwater by PCR and infectivity methods.

AIM: To investigate the potential health hazard from infectious viruses where coliphages, or viruses by polymerase chain reaction (PCR), have been detected in groundwater. Two aspects were investigated: the relationship between infectivity and detection by PCR and the stability of coliphage compared to human viruses. METHODS AND RESULTS: Virus decay (1 year) and detection (2 years) studies were undertaken on groundwater at 12 degrees C. The order of virus stability from most to least stable in groundwater, based on first-order inactivation, was: coliphage PhiX174 (0.5 d(-1)) > adenovirus 2 > coliphage PRD1 > poliovirus 3 > coxsackie virus B1 (0.13 d(-1)). The order for PCR results was: norovirus genotype II > adenovirus > norovirus genotype I > enterovirus. CONCLUSIONS: Enterovirus and adenovirus detection by PCR and the duration of infectivity in groundwater followed similar trends over the time period studied. Adenovirus might be a better method for assessing groundwater contamination than using enterovirus; norovirus detection would provide information on a significant human health hazard. Bacteriophage is a good alternative indicator. SIGNIFICANCE AND IMPACT OF THE STUDY: PCR is a useful tool for identifying the health hazard from faecal contamination in groundwater where conditions are conducive to the survival of viruses and their nucleic acid.