Quantitative analysis of human enteric adenoviruses in aquatic environments

Assessment of Gastroenteric Viruses in Marketed Bivalve Mollusks in the Tourist Cities of Rio de Janeiro, Brazil, 2022

This study investigated the prevalence and genetic diversity of gastroenteric viruses in mussels and oysters in Rio de Janeiro, Brazil. One hundred and thirty-four marketed bivalve samples were obtained between January and December 2022. The viral analysis was performed according to ISO/TS 15216, and the screening revealed the detection of norovirus GII/GI (40.3%), sapovirus (SaV; 12.7%), human mastadenovirus (7.5%), and rotavirus A (RVA; 5.9%). In total, 44.8% (60) of shellfish samples tested positive for one or more viruses, 46.7% (28/60) of the positive samples tested positive for a single viral agent, 26.7% (16) tested positive for two viral agents, 8.3% (5) for three viral agents, and 13.3% (8) for four viral agents. Additionally, three mussel samples were contaminated with the five investigated viruses (5%, 3/60). Norovirus GII showed the highest mean viral load (3.4 × 105 GC/g), followed by SaV (1.4 × 104 GC/g), RVA (1.1 × 104 GC/g), human mastadenovirus (3.9 × 103 GC/g), and norovirus GI (6.7 × 102 GC/g). Molecular characterization revealed that the recovered norovirus strains belonged to genotypes GII.2, GII.6, GII.9, GII.17, and GII.27; SaV belonged to genotypes GI.1 and GIV.1; RVA to genotypes G6, G8, P[8]-III, and human mastadenovirus to types F40 and F41. The GII.27 norovirus characterized in this study is the only strain of this genotype reported in Brazil. This study highlights the dissemination and diversity of gastroenteric viruses present in commercialized bivalves in a touristic area, indicating the potential risk to human health and the contribution of bivalves in the propagation of emerging pathogens.

Detection and quantification of adenovirus, polyomavirus, and papillomavirus in urban sewage

The objective of this study was to assess the occurrence and seasonal frequency of human adenovirus (HAdV), human polyomavirus (HPyV), and human papillomavirus (HPV) in urban sewage. The detection of these viruses was carried out by polymerase chain reaction (PCR), and then the viral concentrations in the positive samples were quantified by quantitative PCR (qPCR). Additionally, HAdV and HPyV genotyping was also performed by PCR. A total of 38/60 (63.3%) positive samples were found. HAdV was the most prevalent virus (26/60; 43.3%), followed by HPyV (21/60; 35%) and HPV (21/60; 35%). The viral concentrations ranged from 3.56 × 102 to 7.55 × 107 genome copies/L. The most common dual viral agents was found between HAdV and HPyV, in eight samples (8/38, 21%). HAdV types 40 and 41 as well as HPyV types JC and BK were identified, with HAdV-40 and HPyV JC being the most prevalent types. Furthermore, the detection rates of HAdV, HPyV, and HPV were higher during the winter season than the other seasons. The high prevalence of HAdV and HPyV supports their suitability as viral indicators of sewage contamination. Furthermore, this study demonstrates the advantages of environmental surveillance as a tool to elucidate the community-circulating viruses.

Molecular analysis of adenovirus strains responsible for gastroenteritis in children, under five, in Tunisia

Purpose of work

Enteric Adenovirus (EAdV) is recognized as one of the most commonly identified agents responsible for severe acute gastroenteritis (AGEs) in the stools of infants.We sought to determine the rate of human adenovirus (HAdV) infections, and the genotypic characterization of circulating strains of HAdV in children under 5 years of age with AGEs in university and regional hospitals, located in the Center-East of Tunisia, from January 2014 to December 2016.

Methods

A classic PCR was performed on 582 stool samples taken within 5 days of the onset of symptoms. Chosen positive samples were sequenced, and some of the results were confirmed by the Next Generation Sequencing technique (NGS). Partial nucleotide sequences of the Hexon gene obtained in this study were compared with the NCBI GenBank database using BLAST. Multiple sequence alignment and phylogenetic analysis were conducted using MEGA6 software. The phylogenetic tree was generated using the maximum-likelihood method and bootstrap analysis was performed with 1000 replications.

Results

Out of 582 samples, 52 (8.93 %) cases were positive for HAdV, with a male predominance (57.4 %). Phylogenetic analyses showed that Tunisian HAdV strains clustered into five HAdV lineages corresponding to serotypes F41 (14/28), C2 (9/28), C5 (3/28), E4 (1/28), and A18 (1/28). HAdV was more frequent in children aged up to 12 months, as compared to the other age groups. The HAdV activity was noted in almost all the months of the year with a peak in autumn, in 2014 and 2015, and in winter in 2016.

Conclusion

This study showed that infections with HAdV species were frequent in children suffering from AGE with the predominance of HAdV F41 and C2. This result underlines the importance of regular monitoring of circulating genotypes, and it could be useful for future epidemiological research.

Integrating life cycle assessment with quantitative microbial risk assessment for a holistic evaluation of sewage treatment plant

An integrated approach was employed in the present study to combine life cycle assessment (LCA) with quantitative microbial risk assessment (QMRA) to assess an existing sewage treatment plant (STP) at Roorkee, India. The midpoint LCA modeling revealed that high electricity consumption (≈ 576 kWh.day^-1) contributed to the maximum environmental burdens. The LCA endpoint result of 0.01 disability-adjusted life years per person per year (DALYs pppy) was obtained in terms of the impacts on human health. Further, a QMRA model was developed based on representative sewage pathogens, including E. coli O157:H7, Giardia sp., adenovirus, norovirus, and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The public health risk associated with intake of pathogen-laden aerosols during treated water reuse in sprinkler irrigation was determined. A cumulative health risk of 0.07 DALYs pppy was obtained, where QMRA risks contributed 86 % of the total health impacts. The annual probability of illness per person was highest for adenovirus and norovirus, followed by SARS-CoV-2, E. coli O157:H7 and Giardia sp. Overall, the study provides a methodological framework for an integrated LCA-QMRA assessment which can be applied across any treatment process to identify the hotspots contributing maximum environmental burdens and microbial health risks. Furthermore, the integrated LCA-QMRA approach could support stakeholders in the water industry to select the most suitable wastewater treatment system and establish regulations regarding the safe reuse of treated water.

Wastewater monitoring in tourist cities as potential sentinel sites for near real-time dynamics of imported SARS-CoV-2 variants

Wastewater-based epidemiology (WBE) complements the clinical surveillance of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and its variants' distribution in populations. Many developed nations have established national and regional WBE systems; however, governance and budget constraints could be obstacles for low- and middle-income countries. An urgent need thus exists to identify hotspots to serve as sentinel sites for WBE. We hypothesized that representative wastewater treatment plants (WWTPs) in two international gateway cities, Bangkok and Phuket, Thailand, could be sentineled for SARS-CoV-2 and its variants to reflect the clinical distribution patterns at city level and serve as early indicators of new variants entering the country. Municipal wastewater samples (n = 132) were collected from eight representative municipal WWTPs in Bangkok and Phuket during 19 sampling events from October 2021 to March 2022, which were tested by reverse transcription-quantitative polymerase chain reaction (RT-qPCR) using the US CDC N1 and N2 multiplex and variant (Alpha, Delta, and Omicron BA.1 and BA.2) singleplex assays. The variant detection ratios from Bangkok and Phuket followed similar trends to the national clinical testing data, and each variant's viral loads agreed with the daily new cases (3-d moving average). Omicron BA.1 was detected in Phuket wastewater prior to Bangkok, possibly due to Phuket's WWTPs serving tourist communities. We found that the Omicron BA.1 and BA.2 viral loads predominantly drove the SARS-CoV-2 resurgence. We also noted a shifting pattern in the Bangkok WBE from a 22-d early warning in early 2021 to a near real-time pattern in late 2021. The potential application of tourist hotspots for WBE to indicate the arrival of new variants and re-emerging or unprecedented infectious agents could support tourism-dependent economies by complementing the reduced clinical regulations while maintaining public health protection via wastewater surveillance.

Adenovirus in fishery harbours and identification of contamination sources

Adenoviruses (AdVs) are a major cause of clinical infections and have been proposed as indicators of water quality. However, quantitative data on the environmental prevalence of AdVs is lacking. We investigated the prevalence, distribution, seasonal occurrence, quantity, and genotype of AdVs in 13 fishing harbours in Taiwan. AdVs in the water samples were isolated by membrane filtration and the AdV DNA was extracted. Next, AdVs were detected using nested polymerase chain reaction. Genotyping and phylogenetic analysis were performed to identify various AdV genotypes present in the water samples. The F species human AdV (HAdV) serotype 41 (63.6%) and C species porcine AdV (PAdV) serotype 5 (33.3%) were more prevalent than the other serotypes. The prevalence of AdVs was highest in the fall, followed by in the spring and summer. Among the fishing harbours, the highest detection rate of AdVs was observed in Yenpudongang in all seasons. However, Puoziliao was the only site at which AdVs were not detected during the study period. AdV detection at sampling sites may be correlated with sewage and livestock wastewater discharge via outflow of nearby rivers to fishing ports. Statistical analysis (Mann-Whitney U test) based on data from water quality indicators revealed that the presence of AdVs was significantly associated with the heterotrophic plate count, pH, and salinity. Human and swine population data from nearby local townships and river/drainage basins were collected from the Taiwan Central Government's website. The data were analyzed using Spearman's rank correlation coefficient to determine the relationship between the prevalence of AdVs, HAdVs, and PAdVs in fishing harbours, and microbial water quality indicators. Statistical evidence indicated that the detection levels of HAdVs and PAdVs in fishing harbours were mainly associated with human and swine populations in the corresponding river/drainage basin, respectively. Additionally, the swine population in the river/drainage basin was positively correlated with microbial water quality indicators.

Surveillance of Adenovirus and Norovirus Contaminants in the Water and Shellfish of Major Oyster Breeding Farms and Fishing Ports in Taiwan

The enteric viruses, including adenovirus (AdVs) and norovirus (NoVs), in shellfish is a significant food safety risk. This study investigated the prevalence, seasonal occurrence, genetic diversity, and quantification of AdVs and NoVs in the water and cultured shellfish samples at the four major coastal oyster breeding farms (COBF), five major fishing ports (FP), and their markets in Taiwan. The AdVs/NoVs in the water and shellfish samples were isolated by the membrane filtration and direct elution methods. The RNA of NoVs was reverse-transcribed into complementary DNA through reverse transcription reaction. Further NoVs and AdVs were detected using nested PCR. A higher detection rate was recorded in the low-temperature period than high-temperature. Detection difference was noted between nested PCR and qPCR outcomes for AdVs. The total detection rate of AdVs was higher in the water samples (COBF-40.6%, FP 20%) than the shellfish samples (COBF-11.7% and FP 6.3%). The AdVs load in the water and shellfish samples ranged from 1.23 × 103 to 1.00 × 106 copies/L and 3.57 × 103 to 4.27 × 104 copies/100g, respectively. The total detection of NoVs was highest in the water samples of the FP and their market shellfish samples (11.1% and 3.2%, respectively). Genotyping and phylogenetic analysis were identified as the prevalent AdVs and NoVs genotypes in the water and shellfish samples: A species HAdVs serotype 12; F species HAdVs serotype 41; and C species PAdVs serotype 5 (NoVs GI.2, GI.3 and GII.2). No significant differences were observed between the presence of AdVs, and all of the water quality parameters evaluated (heterotrophic plate count, water temperature, turbidity, pH, salinity, and dissolved oxygen). The virus contamination occurs mainly due to the direct discharge of domestic sewage, livestock farm, and fishing market wastewater into the coastal environment. Thus, this study suggested framing better estuarine management to prevent AdVs/NoVs transmission in water and cultured/distributed shellfish.

Capacity of existing wastewater treatment plants to treat SARS-CoV-2. A review

Water is one of many viral transmission routes, and the presence of Severe Acute Respiratory Syndrome Corona Virus 2 (SARS-CoV-2) in wastewater has brought attention to its treatment. SARS CoV-2 primarily transmits in the air but the persistence of the virus in the water possibly can serve as a secondary source even though current studies do not show this. In this paper, an evaluation of the current literature with regards to the treatment of SARS-CoV-2 in wastewater treatment plant (WWTP) effluents and biosolids is presented. Treatment efficiencies of WWTPs are compared for viral load reduction on the basis of publicly available data. The results of this evaluation indicate that existing WWTPs are effectively removing 1-6 log₁₀ viable SARS-CoV-2. However, sludge and biosolids provide an umbrella of protection from treatment and inactivation to the virus. Hence, sludge treatment factors like high temperature, pH changes, and predatory microorganisms can effectively inactivate SARS-CoV-2.

Detection of Human Sapoviruses in Sewage in China by Next Generation Sequencing

Human sapovirus (SaV) is an important causative agent of nonbacterial gastroenteritis in humans. However, little is known about its circulation in China. To study the prevalence and diversity of human SaV genotypes circulating in eastern China, a 3-year environmental surveillance combined with next generation sequencing (NGS) technology was conducted. A total of 36 raw sewage samples were collected from January 2017 to December 2019 in Jinan and processed. Thirty-five (97.22%) samples were positive for human SaV genome in quantitative RT-PCR assay; 33 (91.67%) samples were positive in nested RT-PCR assay on partial capsid VP1 sequence and all amplicons were further analyzed separately by NGS. Among those, ten genotypes belonging to the genogroups of GI, GII, GIV, and GV were identified by NGS, including 4 major genotypes (GI.2, GI.1, GV.1 and GI.3) and 6 uncommon genotypes (GII.5, GII.1, GII.NA1, GII.3, GI.6 and GIV.1). A temporal switch of predominant genotype was observed from GI.2 to GI.1 around June 2019. Local and foreign sequences clustered together in some branches according to phylogenetic analysis, indicating frequent transmission of various lineages in different regions of the world. Environmental surveillance provides a comprehensive picture of human SaV in China. NGS-based environmental surveillance improves our knowledge on human SaV circulating in communities greatly and should be encouraged as a sensitive surveillance tool.

Functionalized Surfaces as a Tool for Virus Sensing: A Demonstration of Human mastadenovirus Detection in Environmental Waters

The main goal of this study was to apply magnetic bead surface functionalization in the form of immunomagnetic separation (IMS) combined with real-time polymerase chain reaction (qPCR) (IMS-qPCR) to detect Human mastadenovirus species C (HAdV-C) and F (HAdV-F) in water samples. The technique efficiency was compared to a nonfunctionalized method (ultracentrifugation) followed by laboratory detection. Tests were carried out to standardize IMS parameters followed by tests on 15 water samples concentrated by IMS and ultracentrifugation. Microscopic analyses detected a successful beads–antibody attachment. HAdV was detected up to dilutions of 10−6 by IMS-qPCR, and samples concentrated by IMS were able to infect cell cultures. In water samples, HAdV-C was detected in 60% (monoclonal) and 47% (polyclonal) by IMS-qPCR, while 13% of samples concentrated by ultracentrifugation gave a positive result. HAdV-F was positive in 27% of samples by IMS-qPCR (polyclonal) and ultracentrifugation and 20% by IMS-qPCR (monoclonal). The rate of detection varied from 4.55 × 102 to 5.83 × 106 genomic copies/L for IMS-qPCR and from 2.00 × 102 to 2.11 × 103 GC/L for ultracentrifugation. IMS showed to be a more effective concentration technique for HAdV than ultracentrifugation, improving the assessment of infectious HAdV in water resources.

Reduction of Human Enteric and Indicator Viruses at a Wastewater Treatment Plant in Southern Louisiana, USA

This study assessed wastewater quality through the quantification of four human enteric viruses and the applicability of pepper mild mottle virus (PMMoV) and tobacco mosaic virus (TMV) as indicators of viral reduction during wastewater treatment. Thirty-three samples were collected from three steps of a wastewater treatment plant in Southern Louisiana, USA for a year between March 2017 and February 2018. Noroviruses of genogroup I were the most prevalent human enteric viruses in influent samples. The concentrations of PMMoV in influent samples (5.9 ± 0.7 log₁₀ copies/L) and biologically treated effluent samples (5.9 ± 0.5 log₁₀ copies/L) were significantly higher than those of TMV (P < 0.05), and the reduction ratio of PMMoV (1.0 ± 0.8 log₁₀) was found comparable to those of TMV and Aichi virus 1. Because of the high prevalence, high correlations with human enteric viruses, and lower reduction ratios, PMMoV was deemed an appropriate indicator of human enteric viral reduction during wastewater treatment process.

Viral indicators for tracking domestic wastewater contamination in the aquatic environment

Waterborne enteric viruses are an emerging cause of disease outbreaks and represent a major threat to global public health. Enteric viruses may originate from human wastewater and can undergo rapid transport through aquatic environments with minimal decay. Surveillance and source apportionment of enteric viruses in environmental waters is therefore essential for accurate risk management. However, individual monitoring of the >100 enteric viral strains that have been identified as aquatic contaminants is unfeasible. Instead, viral indicators are often used for quantitative assessments of wastewater contamination, viral decay and transport in water. An ideal indicator for tracking wastewater contamination should be (i) easy to detect and quantify, (ii) source-specific, (iii) resistant to wastewater treatment processes, and (iv) persistent in the aquatic environment, with similar behaviour to viral pathogens. Here, we conducted a comprehensive review of 127 peer-reviewed publications, to critically evaluate the effectiveness of several viral indicators of wastewater pollution, including common enteric viruses (mastadenoviruses, polyomaviruses, and Aichi viruses), the pepper mild mottle virus (PMMoV), and gut-associated bacteriophages (Type II/III FRNA phages and phages infecting human Bacteroides species, including crAssphage). Our analysis suggests that overall, human mastadenoviruses have the greatest potential to indicate contamination by domestic wastewater due to their easy detection, culturability, and high prevalence in wastewater and in the polluted environment. Aichi virus, crAssphage and PMMoV are also widely detected in wastewater and in the environment, and may be used as molecular markers for human-derived contamination. We conclude that viral indicators are suitable for the long-term monitoring of viral contamination in freshwater and marine environments and that these should be implemented within monitoring programmes to provide a holistic assessment of microbiological water quality and wastewater-based epidemiology, improve current risk management strategies and protect global human health.

Performance of the QIAstat-Dx Gastrointestinal Panel for Diagnosing Infectious Gastroenteritis

Detection and identification of enteropathogens that cause infectious gastroenteritis are essential steps for appropriate patient treatment and effective isolation precautions. Several syndrome-based tests have recently become available, with the gastrointestinal panel (GIP) assay on the QIAstat-Dx as the most recent addition to the syndromic testing landscape.

Detection and identification of enteropathogens that cause infectious gastroenteritis are essential steps for appropriate patient treatment and effective isolation precautions. Several syndrome-based tests have recently become available, with the gastrointestinal panel (GIP) assay on the QIAstat-Dx as the most recent addition to the syndromic testing landscape. The QIAstat-Dx GIP assay offers simultaneous testing for 24 bacterial, viral, and parasitic enteropathogens using a single test that reports the results in 70 min. In this study, we compared the performance of the GIP assay to laboratory-developed real-time PCR assays (LDTs), using 172 prospectively and retrospectively collected fecal samples from patients suspected to have infectious gastroenteritis. The GIP assay detected 97/107 enteropathogens (91%) that were detected by LDTs, and the overall agreement of results increased to 95% when excluding discrepant results with cycle threshold (C_T) values of >35. Further, the GIP assay detected 42 additional enteropathogens that were not detected, or tested, by LDTs. These included 35 diarrheagenic Escherichia coli targets for which the clinical relevance is unclear for most. The main advantage of the QIAstat-Dx system compared to other syndromic testing systems is the ability to generate C_T values that could help with the interpretation of results. However, compared to LDTs, the GIP assay is limited by flexibility and high-throughput testing. In conclusion, the GIP assay offers an easy, sample-to-answer workflow with a rapid detection of the most common enteropathogens and therefore has the potential to direct appropriate therapy and infection control precautions.

Characterization of Salmonella Isolates from Wastewater Treatment Plant Influents to Estimate Unreported Cases and Infection Sources of Salmonellosis

Salmonella enterica is a major cause of gastroenteritis usually caused by animal-based contaminated foods. Since the current passive surveillance is not sufficient to detect all infections and infection sources, we determined the prevalence of Salmonella isolated from sewage influent of wastewater treatment plants (WWTPs) and compared the characteristics of human and food isolates to identify the infection sources. Sewage influent samples were collected monthly from two WWTPs located in the Yamanashi Prefecture, Japan, for three years. Serotypes, antimicrobial resistances, isolation periods, isolated areas, and pulsed-field gel electrophoresis patterns of six isolates belonging to five serotypes were consistent with those of the isolates from patients. Real-time PCR for Salmonella indicated that sewage influents reflect cases of patients infected with Salmonella, including unreported cases. Serovars Schwarzengrund and Anatum were predominant in sewage, but not in humans, and their characteristics were closely related or identical to those isolated from poultry heart and liver, respectively. These results suggest that sewage influent contains Salmonella isolates from humans and that some originated from unreported human cases infected by poultry-associated products. Therefore, it is necessary to take countermeasures against Salmonella infection based on the unreported cases, which would be disclosed by analysis of sewage influent.

Linking Microbial Community Composition in Treated Wastewater with Water Quality in Distribution Systems and Subsequent Health Effects

The increases in per capita water consumption, coupled in part with global climate change have resulted in increased demands on available freshwater resources. Therefore, the availability of safe, pathogen-free drinking water is vital to public health. This need has resulted in global initiatives to develop sustainable urban water infrastructure for the treatment of wastewater for different purposes such as reuse water for irrigation, and advanced waste water purification systems for domestic water supply. In developed countries, most of the water goes through primary, secondary, and tertiary treatments combined with disinfectant, microfiltration (MF), reverse osmosis (RO), etc. to produce potable water. During this process the total bacterial load of the water at different stages of the treatment will decrease significantly from the source water. Microbial diversity and load may decrease by several orders of magnitude after microfiltration and reverse osmosis treatment and falling to almost non-detectable levels in some of the most managed wastewater treatment facilities. However, one thing in common with the different end users is that the water goes through massive distribution systems, and the pipes in the distribution lines may be contaminated with diverse microbes that inhabit these systems. In the main distribution lines, microbes survive within biofilms which may contain opportunistic pathogens. This review highlights the role of microbial community composition in the final effluent treated wastewater, biofilms formation in the distribution systems as the treated water goes through, and the subsequent health effects from potential pathogens associated with poorly treated water. We conclude by pointing out some basic steps that may be taken to reduce the accumulation of biofilms in the water distribution systems.

Teschovirus and other swine and human enteric viruses in Brazilian watersheds impacted by swine husbandry

Several emerging viral agents related to gastroenteritis are distributed in human and animal populations and may contaminate the environment due to anthropic activities. The objective of this study was to analyze the seasonal contamination by enteric virus and coliforms in water from streams in the Vale do Taquari, draining a large number of pig farms. Microbiological contamination was evidenced by the detection of total and thermotolerant coliforms, reaching their peak in December. Hepatitis E virus (HEV), Enterovirus-G (EV-G) genome, and Sapelovirus-A (SV-A) genome were not detected. On the other hand, Rotavirus (RV) was detected in 3% (1/32) of the samples, whereas Teschovirus-A (PTV) was detected in 6% (2/32). This is the first detection of PTV in environmental samples in Brazil, pointing that the virus is being shedded from swine herds to watersheds. Human mastadenovirus (HAdV) was the most frequent detected viral agent in 9.3% (3/32) with values of 2.54 × 10⁵, 7.13 × 10⁴, and 3.09 × 10⁵ genome copies/liter (gc/L). The circulation of coliforms and viral pathogens is noticeable due to anthropic activities and to the management of animal waste from the pig farming. In this way, enteric viruses can assist in monitoring the quality of watersheds and in tracking sources of contamination.

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.

Genetic diversity and quantification of human mastadenoviruses in wastewater from Sydney and Melbourne, Australia

Human mastadenoviruses (HAdVs) are DNA viruses that can cause a wide range of clinical diseases, including gastroenteritis, respiratory illnesses, conjunctivitis, and in more severe cases hepatitis, pancreatitis and disseminated diseases. HAdV infections are generally asymptomatic or self-limiting, but can cause adverse outcomes within vulnerable populations. Since most HAdV serotypes replicate within the human gastrointestinal tract, high levels of HAdV DNA are excreted into wastewater systems. In this study, we identified the genetic diversity of HAdV at a population level using wastewater samples collected from Sydney and Melbourne from 2016 to 2017, with the use of next generation sequencing (NGS) technologies. In addition, HAdV DNA levels were quantified using quantitative polymerase chain reaction (qPCR) based methods to better understand the health risks involved if wastewater contamination occurs. An average of 1.8 × 10⁷ genome copies of HAdV DNA was detected in one litre of wastewater collected in Sydney and Melbourne, over the two-year study period. A total of six major groups of HAdV were identified in wastewater samples using MiSeq, which included 19 different serotypes. Of those, the most prevalent was F41 (83.5%), followed by F40 (11.0%) and A31 (3.7%). In contrast, five groups of HAdV were identified in clinical samples with F41 as the most dominant serotype, (52.5% of gastroenteritis cases), followed by C1 and C2 (each responsible for 15.0%), and B3 was the fourth most common serotype (7.5%). This study demonstrated the practicability of using amplicon based NGS to identify HAdV diversity and quantify HAdV genome levels in environmental water samples, as well as broadening our current understanding of circulating HAdV in the Australian population.

A water-focused one-health approach for early detection and prevention of viral outbreaks

Despite consistent efforts to protect public health there is still a heavy burden of viral disease, both in the United States and abroad. In addition to conventional medical treatment, there is a need for a holistic approach for early detection and prevention of viral outbreaks at a population level. One-Health is a relatively new integrative approach to the solving of global health challenges. A key component to the One-Health approach is the notion that human health, animal health, and environmental health are all innately interrelated. One-Health interventions, initiated by veterinary doctors, have proven to be effective in controlling outbreaks, but thus far the applications focus on zoonotic viruses transmitted from animals to humans. Environmental engineers and environmental scientists hold a critical role in the further development of One-Health approaches that include water-related transport and transmission of human, animal, and zoonotic viruses. In addition to waterborne viruses, the proposed approach is applicable to a wide range of viruses that are found in human excrement since contaminated water-based surveillance systems may be used for early detection of viral disease. This paper proposes a greater One-Health based framework that involves water-related pathways. The first step in the proposed framework is the identification of critical exposure pathways of viruses in the water environment. Identification of critical pathways informs the second and third steps, which include water-based surveillance systems for early detection at a population level and implementation of intervention approaches to block the critical pathways of exposure.

Human mastadenovirus in water, sediment, sea surface microlayer, and bivalve mollusk from southern Brazilian beaches

Anthropogenic contamination of beaches in the south of Brazil was assessed by detection of Escherichia coli, human mastadenovirus species C (HAdV-C) and F (HAdV-F) and hepatitis E virus (HEV). Sampling was carried out in October (2016), and in January, April and July (2017). Water, sediment, sea surface microlayer (SML), bivalves, and air sentinel samples were evaluated. Quantitative microbiological risk assessment (QMRA) was used to estimate the probability of swimmer infection. HAdV-C was present in 26% of the samples, for both qPCR and viral isolation. The highest rates of detection in genomic copies (GC) were in water (2.42E+10 GC/L), SML (2.08E+10 GC/L), sediment (3.82E+08 GC/g) and bivalves (3.91E+07 GC/g). QMRA estimated daily and annual risks with a maximum value (9.99E-01) in almost all of the samples. Viable HAdV-C was often detected in the SML, pointing that this is a source of infection for people bathing in these waters.

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.

Molecular detection of human adenovirus in urban wastewater in Egypt and among children suffering from acute gastroenteritis

Incidence of enteric viruses in sewage, the efficacy of wastewater treatment plants to remove these viruses, and health effects from their release into the surface water are very important environmental issues in the microbiology field. One of the most pathogenic enteric viruses is adenovirus which can cause a serious disease such as gastroenteritis with low grade fever and mild dehydration in humans. In this study we performed qualitative polymerase chain reaction (PCR) analysis of HAdV on 60 stool samples from children with acute gastroenteritis admitted to Abu-Rish hospital and 96 environmental samples (32 raw sewage, 32 treated sewage, 32 sewage sludge) collected from Zenin wastewater treatment plant (WWTP). HAdV were detected in 17 (28.3%) of stool, 27 (84.4%) of raw sewage, 16 (50%) of treated sewage and 25 (78%) of sludge samples. The viral concentrations were in the range of 2.02 × 10⁶-7.23 × 10⁶, 8.7 × 10⁵-4.3 × 10⁶, 1.22 × 10⁴-3.7 × 10⁶ and 1.48 × 10⁶-1.77 × 10⁷ GC/mL in stool, raw sewage, treated sewage, and sludge, respectively. HAdV was detected throughout the whole year of sample collection. Moreover, our results suggested that males were more susceptible to adenovirus infections than females. The results indicate that the high incidence of HAdV in the treated sewage may cause adverse health effects.

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.

Quantification of human adenovirus and norovirus in river water in the north-east of France

Human adenoviruses (HAdVs) are a major cause of infection and have been proposed as viral indicators of water quality. Human noroviruses (NoV) are the main cause of viral acute gastroenteritis. Quantitative data on the environmental prevalence of both viruses are needed. The genomes of HAdVs enteric adenovirus type 41 (HAdV41) and noroviruses of genogroups I and II (NoV GGI and GGII) were quantified over a 6-month period in a river located in north-eastern France. The samples were collected downstream from the discharge of a wastewater treatment plant. The viruses were concentrated using a glass wool method and the viral genomes were quantified using digital droplet PCR (ddPCR). All river water samples (15/15) were positive for the genomes of HAdVs, HAdV41, NoV GGI and NoV GGII. Concentrations of HAdVs, HAdV41 and NoV GII genomes were similar and HAdV41 represented ~ 80% of HAdVs. Infectious HAdVs were quantified in these samples using an integrated cell culture-quantitative PCR method (ICC-qPCR); they were detected in 93% (14/15) and quantified in 53% (8/15) of the samples. Thus, infectious HAdVs represented 0.3 to 12.2% of total HAdV particles detected by ddPCR. Infectious HAdV41 particles were found in 73% (11/15) of the samples. This common presence of pathogenic enteric viruses underlines the impact of wastewater discharge on quality of surface waters and may constitute a threat for human health. The relative abundance of genome of HAdV41 underlines the need for studies focusing on the specific detection of its infectious forms along water cycle.

Overview of Trends in the Application of Metagenomic Techniques in the Analysis of Human Enteric Viral Diversity in Africa's Environmental Regimes

There has been an increase in the quest for metagenomics as an approach for the identification and study of the diversity of human viruses found in aquatic systems, both for their role as waterborne pathogens and as water quality indicators. In the last few years, environmental viral metagenomics has grown significantly and has enabled the identification, diversity and entire genome sequencing of viruses in environmental and clinical samples extensively. Prior to the arrival of metagenomics, traditional molecular procedures such as the polymerase chain reaction (PCR) and sequencing, were mostly used to identify and classify enteric viral species in different environmental milieu. After the advent of metagenomics, more detailed reports have emerged about the important waterborne viruses identified in wastewater treatment plant effluents and surface water. This paper provides a review of methods that have been used for the concentration, detection and identification of viral species from different environmental matrices. The review also takes into consideration where metagenomics has been explored in different African countries, as well as the limitations and challenges facing the approach. Procedures including sample processing, experimental design, sequencing technology, and bioinformatics analysis are discussed. The review concludes by summarising the current thinking and practices in the field and lays bare key issues that those venturing into this field need to consider and address.

Characterization of Natural Organic Substances Potentially Hindering RT-PCR-Based Virus Detection in Large Volumes of Environmental Water

Quantitative detection of pathogenic viruses in the environmental water is essential for the assessment of water safety. It is known that some of natural organic substances interfere with virus detection processes, i.e., nucleic acid extraction and reverse transcription-PCR. Such substances are carried over into a sample after virus concentration. In this study, inhibitory substances in coastal water samples were characterized in view of their effects on efficiency of virus detection and property as organic matters. Among 81 samples tested, 77 (95%) showed low recoveries (<10%) of spiked murine norovirus. These recovery rates were correlated with the levels of organic matter present in virus concentrates as measured by ultraviolet absorbance at 254 nm (r = -0.70 - -0.71, p < 0.01). High-performance gel chromatography and fluorescence excitation-emission matrix spectroscopy revealed that organic fractions in the 10-100 kDa size range, which were not dominant in the original samples, and those possessing humic acid-like fluorescence properties were dominant in virus concentrates. The inhibitory effect was more pronounced during summer. Substances originating from seawater seemed to cause a more pronounced effect than those originating from wastewater. Our data highlight the previously unknown characteristics of natural inhibitory substances and are helpful in establishing an effective sample purification technique.

Water treatment with exceptional virus inactivation using activated carbon modified with silver (Ag) and copper oxide (CuO) nanoparticles

Continuous flow experiments (450 mL min^-1) were performed in household filter in order to investigate the removal and/or inactivation of T4 bacteriophage, using granular activated carbon (GAC) modified with silver and/or copper oxide nanoparticles at different concentrations. GAC and modified GAC were characterized by X-ray diffractometry, specific surface area, pore size and volume, pore average diameter, scanning electron microscopy, transmission electron microscopy, zeta potential and atomic absorption spectroscopy. The antiviral activity of the produced porous media was evaluated by passing suspensions of T4 bacteriophage (∼10⁵ UFP/mL) through filters. The filtered water was analyzed for the presence of the bacteriophage and the release of silver and copper oxide. The porous media containing silver and copper oxide nanoparticles showed high inactivation capacity, even reaching reductions higher than 3 log. GAC6 (GAC/Ag0.5%Cu1.0%) was effective in the bacteriophage inactivation, reaching 5.53 log reduction. The levels of silver and copper released in filtered water were below the recommended limits (100 ppb for silver and 1000 ppb for copper) in drinking water. From this study, it is possible to conclude that activated carbon modified with silver and copper oxide nanoparticles can be used as a filter for virus removal in the treatment of drinking water.

Human adenovirus in tissues of freshwater snails living in contaminated waters

Human adenovirus (HAdV) is resistant to environment and can be used as a marker to detect fecal contamination. Considering the importance of freshwater snails in the aquatic environment, their use as concentrators for HAdV is a complementary tool for viral analysis of water. The goal of the study was to detect HAdV in snails and surface water collected from wetlands of the Sinos River (Rio Grande do Sul, Brazil) basin and to compare rates and viral loads found in both samples. HAdV was detected through real-time PCR. Total and fecal coliforms were detected by Colilert^® kit, and viral infectivity of positive samples of the DNA genome was performed in A549 human cell line. All wetlands presented bacterial and viral contamination, but no viral particle was considered viable. The wetland that showed lower fecal coliform mean was Campo Bom, and São Leopoldo (both cities in Rio Grande do Sul) was representative of the highest mean. HAdV was detected in water samples (53%), gastropods' hemolymph (31%) and tissues (16%). Wetlands proved to be environments already altered by human action. Water samples exhibited a higher frequency of HAdV detection; however, in some instances, the target viral genomes were only found in gastropod biological samples. This was a pioneer study in the use of freshwater snails for human enteric viral assessment thus demonstrating that the human organism can retain fecal contamination, complementing and assisting in microbiological water analyzes.

Cellulose-based virus-retentive filters: a review

Viral filtration is a critical step in the purification of biologics and in the monitoring of microbiological water quality. Viral filters are also essential protection elements against airborne viral particles. The present review first focuses on cellulose-based filter media currently used for size-exclusion and/or adsorptive filtration of viruses from biopharmaceutical and environmental water samples. Data from spiking studies quantifying the viral filtration performance of cellulosic filters are detailed, i.e., first, the virus reduction capacity of regenerated cellulose hollow fiber filters in the manufacturing process of blood products and, second, the efficiency of virus recovery/concentration from water samples by the viradel (virus adsorption-elution) method using charge modified, electropositive cellulosic filters or conventional electronegative cellulose ester microfilters. Viral analysis of field water samples by the viradel technique is also surveyed. This review then describes cellulose-based filter media used in individual protection equipment against airborne viral pathogens, presenting innovative filtration media with virucidal properties. Some pros and cons of cellulosic viral filters and perspectives for cellulose-based materials in viral filtration are underlined in the review.

Cross-Comparison of Human Wastewater-Associated Molecular Markers in Relation to Fecal Indicator Bacteria and Enteric Viruses in Recreational Beach Waters

Detection of human wastewater contamination in recreational waters is of critical importance to regulators due to the risks posed to public health. To identify such risks, human wastewater-associated microbial source tracking (MST) markers have been developed. At present, however, a greater understanding of the suitability of these markers for the detection of diluted human wastewater in environmental waters is necessary to predict risk. Here, we compared the process limit of detection (PLOD) and process limit of quantification (PLOQ) of six human wastewater-associated MST markers (Bacteroides HF183 [HF183], Escherichia coli H8 [EC H8], Methanobrevibacter smithiinifH, human adenovirus [HAdV], human polyomavirus [HPyV], and pepper mild mottle virus [PMMoV]) in relation to a fecal indicator bacterium (FIB), Enterococcus sp. 23S rRNA (ENT 23S), and three enteric viruses (human adenovirus serotypes 40/41 [HAdV 40/41], human norovirus [HNoV], and human enterovirus [EV]) in beach water samples seeded with raw and secondary-treated wastewater. Among the six MST markers tested, HF183 was the most sensitive measure of human fecal pollution and was quantifiable up to dilutions of 10^-6 and 10^-4 for beach water samples seeded with raw and secondary-treated wastewater, respectively. Other markers and enteric viruses were detected at various dilutions (10^-1 to 10^-5). These MST markers, FIB, and enteric viruses were then quantified in beach water (n = 12) and sand samples (n = 12) from South East Queensland (SEQ), Australia, to estimate the levels of human fecal pollution. Of the 12 sites examined, beach water and sand samples from several sites had quantifiable concentrations of HF183 and PMMoV markers. Overall, our results indicate that while HF183 is the most sensitive measure of human fecal pollution, it should be used in conjunction with a conferring viral marker to avoid overestimating the risk of gastrointestinal illness.IMPORTANCE MST is an effective tool to help utilities and regulators improve recreational water quality around the globe. Human fecal pollution poses significant public health risks compared to animal fecal pollution. Several human wastewater-associated markers have been developed and used for MST field studies. However, a head-to-head comparison in terms of their performance to detect diluted human fecal pollution in recreational water is lacking. In this study, we cross-compared the performance of six human wastewater-associated markers in relation to FIB and enteric viruses in beach water samples seeded with raw and secondary-treated wastewater. The results of this study will provide guidance to regulators and utilities on the appropriate application of MST markers for tracking the sources of human fecal pollution in environmental waters and confer human health risks.

Diversity of DNA viruses in effluents of membrane bioreactors in Traverse City, MI (USA) and La Grande Motte (France)

This study assesses diversity of DNA viruses in the effluents of two membrane bioreactor (MBR) wastewater treatment plants (WWTPs): an MBR in the United States and an MBR in France. Viral diversity of these effluents is compared to that of a conventional activated sludge WWTP in the U.S. Diversity analysis indicates Herpesvirales to be the most abundant order of potentially pathogenic human DNA viruses in wastewater treated effluent in all utilities. Other potentially pathogenic human viruses detected include Adenoviridae, Parvoviridae, and Polyomaviridae. Bacteriophage order Caudovirales comprises the majority of DNA virus sequences in the effluent of all utilities. The choice of treatment process (MBR versus activated sludge reactor) utilized had no impact on effluent DNA viral diversity. In contrast, the type of disinfection applied had an impact on the viral diversity present in the effluent.

Risk assessment of noroviruses and human adenoviruses in recreational surface waters

In the interest of public health and safety, this study aimed to quantify risks associated with the presence of noroviruses (NoV) and human adenoviruses (HAdV) in an urban catchment area in Singapore. Enteric viruses were quantified using QPCR. NoV were more prevalent in water samples than HAdV, and presented higher associated illness risks across all exposure scenarios. For primary contact recreation of adults and children, mean probability of illness were 0.0061 and 0.0089 for NoV, and 0.0028 and 0.0048 for HAdV. For secondary contact recreation, mean probability of illness were 0.0016 for NoV and 0.00068 for HAdV. Therefore, owing to their prevalence and associated risks, NoV are better suited as reference pathogens in recreational waters in Singapore.

The application of phage-based faecal pollution markers to predict the concentration of adenoviruses in mussels (Mytilus edulis) and their overlying waters

AIM

This study set out to determine whether phage-based indicators may provide a 'low-tech' alternative to existing approaches that might help maintain the microbial safety of shellfish and their overlying waters.

METHODS AND RESULTS

Mussels and their overlying waters were collected biweekly from an estuary in southeast England over a 2-year period (May 2013-April 2015) (n = 48). Levels of bacterial indicators were determined using membrane filtration and most probable number methods and those of bacteriophages were determined by direct plaque assay. The detection of adenovirus was determined using real-time polymerase chain reaction. The results revealed that somatic coliphages demonstrated the most significant correlations with AdV F and G in mussels (ρ = 0·55) and overlying waters (ρ = 0·66), followed by GB124 phages (ρ = 0·43) while Escherichia coli showed no correlation with AdV F and G in mussels.

CONCLUSION

This study demonstrates that the use of somatic coliphages and GB124 phages may provide a better indication of the risk of adenovirus contamination of mussels and their overlying waters than existing bacterial indicators.

SIGNIFICANCE AND IMPACT OF THE STUDY

Phage-based detection may be particularly advantageous in low-resource settings where viral infectious disease presents a significant burden to human health.

Comparison of concentration methods for detection of hepatitis A virus in water samples

Hepatitis A virus is a pathogen associated with water pollution. Contaminated drinking water can cause hepatitis A outbreaks, lead to economic losses, and even threaten human lives. It is difficult to detect low levels of hepatitis A virus in water, so the virus must be concentrated in order to quantify it accurately. Here, we present a simple, rapid, efficient technique for the concentration and detection of hepatitis A virus in water. Our data showed that adding phosphate-buffered saline to the water, pre-filtering the water, and adding Trizol reagent directly to the filtration membrane can significantly improve concentration efficiency. Of three types of filtration membranes studied (mixed cellulose ester membrane, polyvinylidene fluoride membrane, and nylon membrane), the concentration efficiency using mixed cellulose ester membrane with a 0.1-μm pore size was the highest, reaching 92.62 ± 5.17%. This method was used to concentrate hepatitis A virus in water samples from Donghu Lake. Using SYBR Green real-time reverse transcription polymerase chain reaction analysis, the detection sensitivity of this method reached 10(1) copies/μL and its concentration efficiency reached 79.45 ± 9.88%.

Technical aspects of using human adenovirus as a viral water quality indicator

Despite dramatic improvements in water treatment technologies in developed countries, waterborne viruses are still associated with many of cases of illness each year. These illnesses include gastroenteritis, meningitis, encephalitis, and respiratory infections. Importantly, outbreaks of viral disease from waters deemed compliant from bacterial indicator testing still occur, which highlights the need to monitor the virological quality of water. Human adenoviruses are often used as a viral indicator of water quality (faecal contamination), as this pathogen has high UV-resistance and is prevalent in untreated domestic wastewater all year round, unlike enteroviruses and noroviruses that are often only detected in certain seasons. Standard methods for recovering and measuring adenovirus numbers in water are lacking, and there are many variations in published methods. Since viral numbers are likely under-estimated when optimal methods are not used, a comprehensive review of these methods is both timely and important. This review critically evaluates how estimates of adenovirus numbers in water are impacted by technical manipulations, such as during adenovirus concentration and detection (including culturing and polymerase-chain reaction). An understanding of the implications of these issues is fundamental to obtaining reliable estimation of adenovirus numbers in water. Reliable estimation of HAdV numbers is critical to enable improved monitoring of the efficacy of water treatment processes, accurate quantitative microbial risk assessment, and to ensure microbiological safety of water.

Enteric and indicator virus removal by surface flow wetlands

We investigated the occurrence and attenuation of several human enteric viruses (i.e., norovirus, adenovirus, Aichi virus 1, polyomaviruses, and enterovirus) as well as a plant virus, pepper mild mottle virus (PMMoV), at two surface flow wetlands in Arizona. The retention time in one of the wetlands was seven days, whereas in the other wetland it could not be defined. Water samples were collected at the inlet and outlet from the wetlands over nine months, and concentration of viral genomes was determined by quantitative polymerase chain reaction (qPCR). Of the human enteric viruses tested, adenovirus and Aichi virus 1 were found in the greatest prevalence in treated wastewater (i.e., inlet of the wetlands). Reduction efficiencies of enteric viruses by the wetlands ranged from 1 to 3 log10. Polyomaviruses were generally removed to below detection limit, indicating at least 2 to 4 log10 removal. PMMoV was detected in a greater concentration in the inlet of both wetlands for all the viruses tested (10(4) to 10(7) genome copies/L), but exhibited little or no removal (1 log10 or less). To determine the factors associated with virus genome attenuation (as determined by qPCR), the persistence of PMMoV and poliovirus type 1 (an enterovirus) was studied in autoclaved and natural wetland water, and deionized water incubated under three different temperatures for 21 days. A combination of elevated water temperature and biological activities reduced poliovirus by 1 to 4 log10, while PMMoV was not significantly reduced during this time period. Overall, PMMoV showed much greater persistence than human viruses in the wetland treatment.

Distributions of Fecal Markers in Wastewater from Different Climatic Zones for Human Fecal Pollution Tracking in Australian Surface Waters

Recreational and potable water supplies polluted with human wastewater can pose a direct health risk to humans. Therefore, sensitive detection of human fecal pollution in environmental waters is very important to water quality authorities around the globe. Microbial source tracking (MST) utilizes human fecal markers (HFMs) to detect human wastewater pollution in environmental waters. The concentrations of these markers in raw wastewater are considered important because it is likely that a marker whose concentration is high in wastewater will be more frequently detected in polluted waters. In this study, quantitative PCR (qPCR) assays were used to determine the concentrations of fecal indicator bacteria (FIB) Escherichia coli and Enterococcus spp., HFMs Bacteroides HF183, human adenoviruses (HAdVs), and polyomaviruses (HPyVs) in raw municipal wastewater influent from various climatic zones in Australia. E. coli mean concentrations in pooled human wastewater data sets (from various climatic zones) were the highest (3.2 × 10(6) gene copies per ml), followed by those of HF183 (8.0 × 10(5) gene copies per ml) and Enterococcus spp. (3.6 × 10(5) gene copies per ml). HAdV and HPyV concentrations were 2 to 3 orders of magnitude lower than those of FIB and HF183. Strong positive and negative correlations were observed between the FIB and HFM concentrations within and across wastewater treatment plants (WWTPs). To identify the most sensitive marker of human fecal pollution, environmental water samples were seeded with raw human wastewater. The results from the seeding experiments indicated that Bacteroides HF183 was more sensitive for detecting human fecal pollution than HAdVs and HPyVs. Since the HF183 marker can occasionally be present in nontarget animal fecal samples, it is recommended that HF183 along with a viral marker (HAdVs or HPyVs) be used for tracking human fecal pollution in Australian environmental waters.

Development and Evaluation of a Loop-Mediated Isothermal Amplification Assay for the Detection of Adenovirus 40 and 41

Human adenoviruses (hAdVs) of subgroup F (enteric serotypes 40 and 41) display characteristic gut tropism, in vivo, fastidious growth characteristics in cell culture, and are estimated to be associated with 5-20% worldwide of acute gastroenteritis cases among infants and young children. Adequate hAdV gastroenteritis case management requires laboratory-based diagnosis. The present study aimed to the development and evaluation of a simple and cost-effective, one-step, single-tube adenovirus type 40/41 specific loop-mediated isothermal amplification (LAMP) assay for the detection of hAdV40/41 DNA in environmental and/or clinical samples, since no LAMP assay has previously been reported for the detection of these virus types. The assay targeted the hexon gene and had the advantages of being rapid, simple, specific, and sensitive. Results could be obtained within 60 min, under isothermal conditions at 69 °C. The detection limits for hAdV genomes were between 50 and 100 copies/reaction for hAdV40 and hAdV41, and no cross-reactions with other selected viruses, were found. The assay was evaluated with clinical as well as environmental samples. The developed assay is expected to provide a potential molecular tool in obtaining greater knowledge of the hAdV40/41 importance in the epidemiology and clinical manifestations of gastroenteritis.

Sequential and Simultaneous Applications of UV and Chlorine for Adenovirus Inactivation

Adenoviruses are water-borne human pathogens with high resistance to UV disinfection. Combination of UV treatment and chlorination could be an effective approach to deal with adenoviruses. In this study, human adenovirus 5 (HAdV-5) was challenged in a bench-scale experiment by separate applications of UV or chlorine and by combined applications of UV and chlorine in either a sequential or simultaneous manner. The treated samples were then propagated in human lung carcinoma epithelial cells to quantify the log inactivation of HAdV-5. When the processes were separate, a fluence of 100 mJ/cm(2) and a CT value of 0.02 mg min/L were required to achieve 2 log inactivation of HAdV-5 by UV disinfection and chlorination, respectively. Interestingly, synergistic effects on the HAdV-5 inactivation rates were found in the sequential process of chlorine followed by UV (Cl2-UV) (p < 0.05, ANCOVA) in comparison to the separate processes or the simultaneous application of UV/Cl2. This implies that a pretreatment with chlorine may increase the sensitivity of the virus to the subsequent UV disinfection. In conclusion, this study suggests that the combined application of UV and chlorine could be an effective measure against adenoviruses as a multi-barrier approach in water disinfection.

Incidence of human adenoviruses and Hepatitis A virus in the final effluent of selected wastewater treatment plants in Eastern Cape Province, South Africa

BACKGROUND

Municipal effluent constitutes a large reservoir of human enteric viruses and bacteria. Contemporary monitoring practices rely on indicator bacteria, and do not test for viruses. Different viruses, including Norwalk-like viruses, Hepatitis A virus (HAV), adenoviruses, and rotaviruses, are important agents of illnesses in humans. The burden of disease caused by adenoviruses manifests as pneumonia, bronchiolitis, otitis media, conjunctivitis, and tonsillitis, whereas HAV infection can manifest as acute inflammatory diseases of the liver, fever, anorexia, malaise, nausea, and abdominal discomfort, followed by jaundice and dark urine. The public health implications of these viruses depend upon the physiological status of the wastewater microbial community.

METHODS

The occurrence of human adenovirus (HAdV) and HAV was determined in the final effluents of five wastewater treatment plants (WWTPs) in the Eastern Cape, South Africa, over 12 months (September 2012-August 2013). The viruses were detected with real-time PCR, and conventional PCR was used for serotyping.

RESULTS

Adenovirus was detected in effluent samples from all five WWTPs and in 64 % of the total samples, whereas HAV was not detected in any effluent sample. At WWPT-A, samples were collected from the final effluent tank (adenoviral concentrations ranged from 1.05 × 10(1) to 1.10 × 10(4) genome/L, with a 41.7 % detection rate) and the discharge point (adenoviral concentrations ranged between 1.2 × 10(1) and 2.8 × 10(4) genome/L, with a 54.5 % detection rate). At WWPT-B, HAdV was detected in 91.7 % of samples, with viral concentrations of 7.92 × 10(1)-2.37 × 10(5) genome/L. The HAdV concentrations at WWPT-C were 5.32 × 10(1)-2.20 × 10(5) genome/L, and the detection rate was 75 %. The adenoviral concentrations at WWPT-D were 1.23 × 10(3)-1.05 × 10(4) genome/L, and the detection rate was 66.7 %. At WWPT-E, the viral concentrations were 1.08 × 10(1)-5.16 × 10(4) genome/L, and the detection rate was 54.5 %. Characterization of the adenoviruses revealed HAdV serotypes 2 (1.4 %) and 41 (7.1 %), in species C and F, respectively.

CONCLUSIONS

This study is the first to report the prevalence of HAdV in the final effluents of WWTPs in the Eastern Cape, South Africa. The adenoviral detection rates indicate the potential contamination of the environment, with adverse effects on public health.

Human Adenovirus Diversity in Water Samples Using a Next-Generation Amplicon Sequencing Approach

This study aims to establish a straightforward and original workflow for high-throughput typing of human adenoviruses (HAdVs) in environmental samples. Occurrence of HAdVs in water is well documented worldwide, but data on diversity of HAdV types circulating in water are scarcely available. Here, the characterisation of viral particles was performed by determination of amplicon sequences using a next-generation sequencing (NGS) approach. Adenoviral DNA was either directly isolated from wastewater or river water concentrates or after a cell culture passage. Genome amplification targeted a hyper variable region of the hexon gene, allowing the discrimination of the 54 human adenoviral types described until now. After read generation on the benchtop MiSeq platform (Illumina), data were analysed using the Mothur software for identification of all HAdV species and types simultaneously present in a unique sample. NGS results showed a relatively wide HAdV diversity of up to six types in one sample, whereas Sanger sequencing always only retrieved the dominant one. Detected types included HAdV-1, HAdV-2, HAdV-3, HAdV-6, HAdV-12, HAdV-31, HAdV-40 and HAdV-41, HAdV-41 being the most abundant in tested samples. In addition, the influence of the cell line (A549 vs 293A cells) on the infectious HAdV typing results was clearly determined. The 293A appeared to be the most suitable cell line allowing the detection of a larger diversity of infectious HAdVs and reflecting a more realistic initial species distribution than using the A549 cells. These findings demonstrated the feasibility of amplicon sequencing NGS approach to identify viruses in complex environmental water samples.

Applicability of integrated cell culture quantitative PCR (ICC-qPCR) for the detection of infectious adenovirus type 2 in UV disinfection studies

Practical difficulties of the traditional adenovirus infectivity assay such as intensive labor requirements and longer turnaround period limit the direct use of adenovirus as a testing microorganism for systematic, comprehensive disinfection studies. In this study, we attempted to validate the applicability of integrated cell culture quantitative PCR (ICC-qPCR) as an alternative to the traditional cell culture method with human adenovirus type 2 (HAdV2) in a low-pressure UV disinfection study and to further optimize the procedures of ICC-qPCR for 24-well plate format. The relatively high stability of the hexon gene of HAdV2 was observed after exposure to UV radiation, resulting in a maximum gene copy reduction of 0.5 log10 at 280 mJ cm(-2). Two-day post-inoculation incubation period and a maximum spiking level of 10(5) MPN mL(-1) were selected as optimum conditions of ICC-qPCR with the tested HAdV2. An approximate 1:1 correlation of virus quantities by the traditional and ICC-qPCR cell culture based methods suggested that ICC-qPCR is a satisfactory alternative for practical application in HAdV2 disinfection studies. ICC-qPCR results, coupled with a first-order kinetic model (i.e., the inactivation rate constant of 0.0232 cm(2) mJ(-1)), showed that an UV dose of 172 mJ cm(-2) achieved a 4-log inactivation credit for HAdV2. This estimate is comparable to other studies with HAdV2 and other adenovirus respiratory types. The newly optimized ICC-qPCR shows much promise for further study on its applicability of other slow replicating viruses in disinfection studies.

Tracking novel adenovirus in environmental and human clinical samples: no evidence of endemic human adenovirus type 58 circulation in Córdoba city, Argentina

In recent years, several types of human adenovirus (HAdV) have arisen from the recombination between two or more previously known HAdV types, but their epidemiology is poorly understood. In this study, we investigated the circulation of HAdV-58, a recently described HAdV isolated from an HIV-positive patient in Córdoba city, Argentina. For this purpose, a 30-month survey was conducted to study the presence of this type of adenovirus in sewage samples collected at the inlet from a wastewater treatment plant in Córdoba city, Argentina. Complementarily, the virus was sought in stools of HIV-positive patients. Although HAdVs were detected in human stool samples and in a high percentage of sewage samples, no evidence of HAdV-58 circulation was detected. We suggest that there is no endemic circulation of HAdV-58 in the geographical local area. The trend is that the number of identified HAdVs increases over time. In this context, understanding the current circulating HAdVs may be biologically relevant.

Viability of human adenovirus from hospital fomites

The monitoring of environmental microbial contamination in healthcare facilities may be a valuable tool to determine pathogens transmission in those settings; however, such procedure is limited to bacterial indicators. Viruses are found commonly in those environments and are rarely used for these procedures. The aim of this study was to assess distribution and viability of a human DNA virus on fomites in an Adult Intensive Care Unit of a private hospital in Rio de Janeiro, Brazil. Human adenoviruses (HAdV) were investigated in 141 fomites by scraping the surface area and screening by quantitative PCR (qPCR) using TaqMan® System (Carlsbad, CA). Ten positive samples were selected for virus isolation in A549 and/or HEp2c cell lines. A total of 63 samples (44.7%) were positive and presented viral load ranging from 2.48 × 10(1) to 2.1 × 10(3) genomic copies per millilitre (gc/ml). The viability was demonstrated by integrated cell culture/nested-PCR in 5 out of 10 samples. Nucleotide sequencing confirmed all samples as HAdV and characterized one of them as specie B, serotype 3 (HAdV-3). The results indicate the risk of nosocomial transmission via contaminated fomites and point out the use of HAdV as biomarkers of environmental contamination.

Evaluation of human adenovirus and human polyomavirus as indicators of human sewage contamination in the aquatic environment

Discharge of inadequately treated human wastewater into surface waters used for recreation, drinking water, irrigation and shellfish cultivation may present a public health hazard due to the potential shedding of high concentrations of pathogenic viruses from the human gastrointestinal tract. Human adenovirus (HAdV) and human polyomavirus (HPyV) are ubiquitous in humans and have excellent survival characteristics in the environment, so are potential candidates for indicators of human sewage contamination. Using qPCR assays, the prevalence and quantity of HAdV and HPyV JC and BK were determined in influent and effluent wastewater and receiving waters (river, urban stream, estuarine), then compared with norovirus (NoV) presence, a significant human pathogen which is not necessarily ubiquitously excreted into the environment. HAdV and HPyV were frequently detected in high concentrations in wastewater and wastewater-contaminated waters confirming their use as potential indicators for the presence of human sewage. Overall, there was a correlation between the presence of HAdV and HPyV with NoV but there were some notable exceptions including the higher frequency of NoV compared to HAdV and HPyV in estuarine waters impacted by wastewater overflows. We found that HAdV and HPyV detection by qPCR was a suitable tool for evaluating water quality and that their detection can aid in determining pollution sources, thus providing useful information for health risk assessments.

Bayesian Modeling of Enteric Virus Density in Wastewater Using Left-Censored Data

Stochastic models are used to express pathogen density in environmental samples for performing microbial risk assessment with quantitative uncertainty. However, enteric virus density in water often falls below the quantification limit (non-detect) of the analytical methods employed, and it is always difficult to apply stochastic models to a dataset with a substantially high number of non-detects, i.e., left-censored data. We applied a Bayesian model that is able to model both the detected data (detects) and non-detects to simulated left-censored datasets of enteric virus density in wastewater. One hundred paired datasets were generated for each of the 39 combinations of a sample size and the number of detects, in which three sample sizes (12, 24, and 48) and the number of detects from 1 to 12, 24 and 48 were employed. The simulated observation data were assigned to one of two groups, i.e., detects and non-detects, by setting values on the limit of quantification to obtain the assumed number of detects for creating censored datasets. Then, the Bayesian model was applied to the censored datasets, and the estimated mean and standard deviation were compared to the true values by root mean square deviation. The difference between the true distribution and posterior predictive distribution was evaluated by Kullback-Leibler (KL) divergence, and it was found that the estimation accuracy was strongly affected by the number of detects. It is difficult to describe universal criteria to decide which level of accuracy is enough, but eight or more detects are required to accurately estimate the posterior predictive distributions when the sample size is 12, 24, or 48. The posterior predictive distribution of virus removal efficiency with a wastewater treatment unit process was obtained as the log ratio posterior distributions between the posterior predictive distributions of enteric viruses in untreated wastewater and treated wastewater. The KL divergence between the true distribution and posterior predictive distribution of virus removal efficiency also depends on the number of detects, and eight or more detects in a dataset of treated wastewater are required for its accurate estimation.

Rare types of rotaviruses isolated from children with acute gastroenteritis in Patras, Greece

BACKGROUND

Acute diarrhea remains a major public health issue worldwide, with gastroenteritis agents associated with a high morbidity, especially in infants and young children. A 1-year study (2009-2010) of rotavirus (RV)-caused pediatric diarrhea was performed on hospitalized children admitted with symptoms of acute diarrhea to the University Hospital of Patras, Greece.

METHODS

Twenty-nine fecal samples were investigated for RVs, adenoviruses (AdVs), and enteroviruses (EVs) in an attempt to characterize these enteric viruses, which have been implicated in hospitalized diarrhea.

RESULTS

A 44.8% (13/29) incidence of viral infection was reported for the viral targets. Monoinfections accounted for 31% (9/29), while bi-infections accounted for 13.4% (4/29). Sequencing of positive samples allowed identification of RVs G4P[8] (2/29), G9P[8] (1/29), and interestingly of the rare type G12P[8] (2/29). AdV types 1, 2, and 6 were also identified in 4/29, 1/29, and 1/29 of the samples, respectively. Regarding the EVs, EV71 (2/29), coxsackievirus A4 (1/29), echovirus 11 (1/29), and EV96 (1/29) were typed.

CONCLUSION

The results of the present study, and specifically the detection of rare RV G12 and EV71 strains, address the need for continuous epidemiological surveys to provide epidemiological pictures of pediatric viral infections circulating in the community.

An improved infectivity assay combining cell culture with real-time PCR for rapid quantification of human adenoviruses 41 and semi-quantification of human adenovirus in sewage

A protocol for the rapid detection and semi-quantification of human enteric adenovirus based on the quantification of viral mRNA during cell culture infectivity assay was developed. Infectivity assays for adenovirus incorporated cell culture and reverse transcription real-time PCR, where viral mRNA detection was used to monitor the progress of adenovirus infection (CC/mRNA qPCR). The cell line used was G293. This specific infectivity assay was calibrated against different initial concentrations of human adenovirus 41. In addition, the expression of the host's housekeeping (HK) gene, GAPDH, served as internal control for the mRNA assays for quality assurance of the mRNA extraction and reverse transcription steps. The concentrations of infectious human adenoviruses in different sewage samples were estimated semi-quantitatively using the CC/mRNA qPCR assay and calibration obtained for adenovirus 41. A linear relationship between concentrations of viral mRNA (hexon gene) and infectious units was observed between 10(7) to 10(1) infectious units per assay (R(2) = 0.97) in samples analyzed 3-5 days post infection. The expressions of host cell GAPDH gene were not significantly affected by infections with different concentrations of human adenovirus 41, and between virus positive and negative cell cultures (p > 0.1). The estimated concentrations of human adenoviruses in sewage samples ranged between 10(2) to 10(3) mRNA-IU/L. Most of the viruses detected in sewage samples were from human adenovirus species F. The CC/mRNA qPCR assay can be used for quantifying infectious human adenovirus 41, estimating the levels of human adenoviruses in sewage samples, and applied to other sample settings. The CC/mRNA qPCR protocol described here represents an improvement in the detection of human enteric adenoviruses by reducing incubation time (5 days); whereas the conventional cell culture method requires longer incubation periods (10-20 days). More importantly, this protocol can be used to more rapidly and semi-quantitatively estimate the levels of infectious human adenoviruses in environmental samples.