Environmental dissemination of group A rotavirus: P-type, G-type and subgroup characterization

Virological Characterization of Roof-Harvested Rainwater of Densely Urbanized Low-Income Region

Roof-harvested rainwater (RHRW) is considered relatively clean water, even though the possible presence of pathogens in the water may pose human health risks. In this study, we investigated the occurrence of enteric viruses in the first flush (10 mm) of RHRW from a densely populated and low-income urbanized region of Rio de Janeiro. One hundred samples (5 L) were collected from 10 rainfall events between April 2015 and March 2017. RNA and DNA viruses were concentrated using the skimmed milk flocculation method and analyzed using the TaqMan® quantitative RT-qPCR and qPCR. Human adenoviruses, noroviruses, rotaviruses A, and avian parvoviruses were detected in 54%, 31%, 12%, and 12% of the positive samples. JC polyomavirus, also targeted, was not detected. Virus concentrations ranged from 1.09 × 10¹ to 2.58 × 10³ genome copies/Liter (GC/L). Partial nucleotide sequence confirmed the presence of HAdV type 41, norovirus genotype GII.4, and avian parvovirus 1. The results suggest that the first flush diversion devices may not adequately remove enteric virus from the rainwater. Additional treatment of RHRW is required to mitigate potential health risks from potable use of captured water.

Quantitative detection of human adenovirus from river water by monolithic adsorption filtration and quantitative PCR

Water contaminated with fecally derived viruses, also known as enteric viruses, represents a particularly high risk for human health. However, they have not been included in water quality regulations yet. The detection of these viruses is often more expensive and time-consuming compared to the analysis of conventional fecal indicator organisms. In addition, most methods are not sensitive enough to detect small viral loads that may already cause serious health issues if present in water. In this study, we established a workflow for the successful and direct enrichment of human adenovirus (HAdV) from artificially contaminated river water based on monolithic adsorption filtration (MAF) and quantitative polymerase reaction (qPCR). With a clear focus on efficiency, we used targeted synthetic DNA fragments as standard for the quantification of HAdV by qPCR, leading to accurate and robust results with a qPCR efficiency of 95 %, a broad working range over 6 orders of magnitude and an LOD of 1 GU/μL. We carried out a cascade of spiking experiments, enhancing the complexity of the spiking matrix with each step to progressively evaluate MAF for the direct concentration of HAdV. We found that negatively charged MAF using monoliths with hydroxyl groups (MAF-OH) showed a better reproducibility and a significantly faster turnaround time than skimmed milk flocculation (SMF) when concentrating HAdV35 from artificially contaminated, acidified mineral water. We then validated positively charged MAF using monoliths with diethyl aminoethyl groups (MAF-DEAE) for the direct concentration of HAdV5 without pre-conditioning of water samples using tap water as spiking matrix with a less defined and controlled water chemistry. Finally, we evaluated MAF-DEAE for the direct concentration of HAdV5 from surface water using river water as representative matrix with an undefined water chemistry. We found, that MAF-DEAE achieved reproducible recoveries of HAdV5, independently of the spiked concentration level or sample volume. Furthermore, we showed, that MAF-DEAE drastically reduced the limit of detection (LOD) of HAdV5 by a factor of 115 from 6.0 ∙ 10³ GU/mL before to 5.2 ∙ 10¹ GU/mL after MAF-DEAE. We identified that recoveries increased for smaller processing volumes with a peak at 0.5 L of 84.0 % and showed that recovery efficiency depends on sample volume and matrix type. The here presented workflow based on MAF-DEAE and qPCR offers an easy-to-implement and highly efficient alternative to existing approaches and allows for a fast detection of HAdV in water.

Viruses in wastewater: occurrence, abundance and detection methods

This paper presents an updated and comprehensive review on the different methods used for detection and quantification of viruses in wastewater treatment systems. The analysis of viability of viruses in wastewater and sludge is another thrust of this review. Recent studies have mostly focused on determining the abundance and diversity of viruses in wastewater influents, in samples from primary, secondary, and tertiary treatment stages, and in final effluents. A few studies have also examined the occurrence and diversity of viruses in raw and digested sludge samples. Recent efforts to improve efficiency of virus detection and quantification methods in the complex wastewater and sludge matrices are highlighted in this review. A summary and a detailed comparison of the pre-treatment methods that have been utilized for wastewater and sludge samples are also presented. The role of metagenomics or sequencing analysis in monitoring wastewater systems to predict disease outbreaks, to conduct public health surveillance, to assess the efficiency of existing treatment systems in virus removal, and to re-evaluate current regulations regarding pathogenic viruses in wastewater is discussed in this paper. Challenges and future perspectives in the detection of viruses, including emerging and newly emerged viruses such as the Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), in wastewater systems are discussed in this review.

High Prevalence of Rotavirus A in Raw Sewage Samples from Northeast Spain

Rotavirus A (RVA) is the most common virus associated with infantile gastroenteritisworldwide, being a public health threat, as it is excreted in large amounts in stool and can persist inthe environment for extended periods. In this study, we performed the detection of RVA and humanadenovirus (HAdV) by TaqMan qPCR and assessed the circulation of RVA genotypes in threewastewater treatment plants (WWTPs) between 2015 and 2016 in Catalonia, Spain. RVA wasdetected in 90% and HAdV in 100% of the WWTP samples, with viral loads ranging between 3.96 ×104 and 3.30 × 108 RT-PCR Units/L and 9.51 × 104 and 1.16 × 106 genomic copies/L, respectively. RVAVP7 and VP4 gene analysis revealed the circulation of G2, G3, G9, G12, P[4], P[8], P[9] and P[10].Nucleotide sequencing (VP6 fragment) showed the circulation of I1 and I2 genotypes, commonlyassociated with human, bovine and porcine strains. It is important to mention that the RVA strainsisolated from the WWTPs were different from those recovered from piglets and calves living in thesame area of single sampling in 2016. These data highlight the importance of monitoring watermatrices for RVA epidemiology and may be a useful tool to evaluate and predict possibleemergence/reemergence of uncommon strains in a region.

Surveillance of Enteric Viruses and Thermotolerant Coliforms in Surface Water and Bivalves from a Mangrove Estuary in Southeastern Brazil

This study was conducted to evaluate the microbiological quality of a mangrove estuary in the Vitória Bay region, Espírito Santo, Brazil. We analyzed the presence and concentration of enteric viruses and thermotolerant coliforms in water, mussels (Mytella charruana and Mytella guyanensis), and oysters (Crassostrea rhizophorae), collected over a 13-month period. Human adenovirus, rotavirus A (RVA), and norovirus genogroup II were analyzed by quantitative PCR. The highest viral load was found in RVA-positive samples with a concentration of 3.0 × 10⁴ genome copies (GC) L^-1 in water samples and 1.3 × 10⁵ GC g^-1 in bivalves. RVA was the most prevalent virus in all matrices. Thermotolerant coliforms were quantified as colony-forming units (CFU) by the membrane filtration method. The concentration of these bacteria in water was in accordance with the Brazilian standard for recreational waters (< 250 CFU 100 mL^-1) during most of the monitoring period (12 out of 13 months). However, thermotolerant coliform concentrations of 3.0, 3.1, and 2.6 log CFU 100 g^-1 were detected in M. charruana, M. guyanensis, and C. rhizophorae, respectively. The presence of human-specific viruses in water and bivalves reflects the strong anthropogenic impact on the mangrove and serves as an early warning of waterborne and foodborne disease outbreaks resulting from the consumption of shellfish and the practice of water recreational activities in the region.

Adenovirus and rotavirus recovery from a treated effluent through an optimized skimmed-milk flocculation method

Sewage treatment may be insufficient for the complete removal of enteric viruses, such as human adenoviruses (HAdV) and group A rotavirus (RVA). The differences in the efficiency of the treatment methodologies used may interfere with the detection of these viruses. The objective of this study was to optimize a skimmed-milk flocculation technique for the recovery of HAdV and RVA in the samples of treated effluent. The treated effluent collected at the wastewater treatment plant (WWTP) was processed via four protocols including modifications in the initial centrifugation step and the final concentration of skimmed-milk. The viral load and recovery rate were determined by quantitative PCR TaqMan® System. The highest recovery rates of HAdV, RVA, and bacteriophage PP7 (internal control process) were obtained when the concentration of skimmed-milk was doubled and no centrifugation step was used for the sample clarification. The optimized protocol was assessed in a field study conducted with 24 treated effluent samples collected bi-monthly during 2015. HAdV and RVA were detected in 50.0% (12/24) and 33.3% (08/24) of the samples tested, respectively, throughout the year, without seasonal variation (p > 0.05). This study corroborates the use of the organic flocculation method for virus recovery in environmental samples with the adaptation of the protocols to different aquatic matrices.

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

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

Global occurrence and emission of rotaviruses to surface waters

Group A rotaviruses (RV) are the major cause of acute gastroenteritis in infants and young children globally. Waterborne transmission of RV and the presence of RV in water sources are of major public health importance. In this paper, we present the Global Waterborne Pathogen model for RV (GloWPa-Rota model) to estimate the global distribution of RV emissions to surface water. To our knowledge, this is the first model to do so. We review the literature to estimate three RV specific variables for the model: incidence, excretion rate and removal during wastewater treatment. We estimate total global RV emissions to be 2 × 1018 viral particles/grid/year, of which 87% is produced by the urban population. Hotspot regions with high RV emissions are urban areas in densely populated parts of the world, such as Bangladesh and Nigeria, while low emissions are found in rural areas in North Russia and the Australian desert. Even for industrialized regions with high population density and without tertiary treatment, such as the UK, substantial emissions are estimated. Modeling exercises like the one presented in this paper provide unique opportunities to further study these emissions to surface water, their sources and scenarios for improved management.

Rotavirus genotypes in sewage treatment plants and in children hospitalized with acute diarrhea in Italy in 2010 and 2011

Although the molecular surveillance network RotaNet-Italy provides useful nationwide data on rotaviruses causing severe acute gastroenteritis in children in Italy, scarce information is available on rotavirus circulation in the general Italian population, including adults with mild or asymptomatic infection. We investigated the genotypes of rotaviruses present in urban wastewaters and compared them with those of viral strains from clinical pediatric cases. During 2010 and 2011, 285 sewage samples from 4 Italian cities were tested by reverse transcription-PCRs (RT-PCRs) specific for rotavirus VP7 and VP4 genes. Rotavirus was detected in 172 (60.4%) samples, 26 of which contained multiple rotavirus G (VP7 gene) genotypes, for a total of 198 G types. Thirty-two samples also contained multiple P (VP4 gene) genotypes, yielding 204 P types in 172 samples. Genotype G1 accounted for 65.6% of rotaviruses typed, followed by genotypes G2 (20.2%), G9 (7.6%), G4 (4.6%), G6 (1.0%), G3 (0.5%), and G26 (0.5%). VP4 genotype P[8] accounted for 75.0% of strains, genotype P[4] accounted for 23.0% of strains, and the uncommon genotypes P[6], P[9], P[14], and P[19] accounted for 2.0% of strains altogether. These rotavirus genotypes were also found in pediatric patients hospitalized in the same areas and years but in different proportions. Specifically, genotypes G2, G9, and P[4] were more prevalent in sewage samples than among samples from patients, which suggests either a larger circulation of the latter strains through the general population not requiring medical care or their greater survival in wastewaters. A high level of nucleotide identity in the G1, G2, and G6 VP7 sequences was observed between strains from the environment and those from patients.

Virologia ambiental e saneamento no Brasil: uma revisão narrativa

Os serviços de saneamento básico têm papel fundamental no controle da transmissão de diversos agentes patogênicos de veiculação hídrica, especialmente vírus responsáveis por causar gastroenterites agudas e hepatites. Entre os agentes virais de maior impacto para a saúde pública, podem ser destacados os vírus das hepatites A, os rotavírus e norovírus, adenovírus e enterovírus, os quais são responsáveis pela contaminação de diversos ecossistemas aquáticos brasileiros. A alta circulação de vírus no ambiente vem sendo relacionada às condições sanitárias inadequadas das comunidades, incluindo a falta na cobertura de serviços ou ineficácia de tecnologias convencionais na eliminação ou redução da carga viral presente na água ou no esgoto. Este estudo aborda uma revisão das relações entre virologia, saúde e saneamento, enfatizando a epidemiologia das infecções virais de transmissão hídrica e o impacto na saúde pública.

One year environmental surveillance of rotavirus specie A (RVA) genotypes in circulation after the introduction of the Rotarix® vaccine in Rio de Janeiro, Brazil

Rotavirus specie A (RVA) infection is the leading cause of severe acute diarrhea among young children worldwide. To reduce this major RVA health impact, the Rotarix® vaccine (GlaxoSmithKline, Rixensart, Belgium) was introduced in the Brazilian Expanded Immunization Program in March 2006 and became available to the entire birth cohort. The aim of this study was to evaluate the spread of RVA in the environment after the introduction of Rotarix® in Brazil. For this purpose, a Wastewater Treatment Plant (WTP) in Rio de Janeiro was monitored for one year to detect, characterize and discriminate RVA genotypes and identify possible circulation of vaccine strains. Using TaqMan® quantitative PCR (qPCR), RVA was detected in 100% (mean viral loads from 2.40×10(5) to 1.16×10(7) genome copies (GC)/L) of sewage influent samples and 71% (mean viral loads from 1.35×10(3) to 1.64×10(5)GC/L) of sewage effluent samples. The most prevalent RVA genotypes were P[4], P[6] and G2, based on VP4 and VP7 classification. Direct nucleotide sequencing (NSP4 fragment) and restriction enzyme digestion (NSP3) analysis did not detect RVA vaccine-like strains from the sewage samples. These data on RVA detection, quantification and molecular characterization highlight the importance of environmental monitoring as a tool to study RVA epidemiology in the surrounding human population and may be useful on ongoing vaccine monitoring programs, since sewage may be a good screening option for a rapid and economical overview of the circulating genotypes.

Reassortant group A rotavirus from straw-colored fruit bat (Eidolon helvum)

TOC summary: Bats may be reservoirs of zoonotic viruses that threaten human health.

Bats are known reservoirs of viral zoonoses. We report genetic characterization of a bat rotavirus (Bat/KE4852/07) detected in the feces of a straw-colored fruit bat (Eidolon helvum). Six bat rotavirus genes (viral protein [VP] 2, VP6, VP7, nonstructural protein [NSP] 2, NSP3, and NSP5) shared ancestry with other mammalian rotaviruses but were distantly related. The VP4 gene was nearly identical to that of human P[6] rotavirus strains, and the NSP4 gene was closely related to those of previously described mammalian rotaviruses, including human strains. Analysis of partial sequence of the VP1 gene indicated that it was distinct from cognate genes of other rotaviruses. No sequences were obtained for the VP3 and NSP1 genes of the bat rotavirus. This rotavirus was designated G25-P[6]-I15-R8(provisional)-C8-Mx-Ax-N8-T11-E2-H10. Results suggest that several reassortment events have occurred between human, animal, and bat rotaviruses. Several additional rotavirus strains were detected in bats.

Quantification and molecular characterization of enteric viruses detected in effluents from two hospital wastewater treatment plants

Hospital wastewater has been described as an important source of spreading pathogenic microorganisms in the environment. However, there are few studies reporting the presence and concentrations of gastroenteric viruses and hepatitis A viruses in these environmental matrices. The aim of this study was to assess the contamination by viruses responsible for acute gastroenteritis and hepatitis derived from hospital wastewater treatment plants (WWTPs). Rotavirus A (RV-A), human adenoviruses (HAdV), norovirus genogroup I and II (NoV GI/GII) and hepatitis A viruses (HAV) were detected and quantified in sewage samples from two WWTPs located in Rio de Janeiro (Brazil) that operates different sewage treatments. WWTP-1 uses an Upflow Anaerobic Sludge Blanket (UASB reactor) and three serial anaerobic filters while WWTP-2 uses aerobic processes, activated sludge with extended aeration and final chlorination of the effluents. Viruses' detection was investigated by using conventional PCR/RT-PCR, quantitative real-time PCR (qPCR) and partial sequencing of the genome of the viruses detected. Rate of viruses detection ranged from 7% (NoV GI in WWTP-1) to 95% (RV-A in WWTP-2) and genome from all viruses were detected. The most prevalent genotypes were RV-A SG I, HAdV species D and F, NoV GII/4 and HAV subgenotype IA. Mean values of viral loads (genome copies (GC)/ml) obtained in filtered effluents from anaerobic process was 1.9 × 10(3) (RV-A), 2.8 × 10(3) (HAdV) and 2.4 × 10(3) (NoV GII). For chlorinated effluents from activated sludge process, the mean values of viral loads (GC/ml) was 1.2 × 10(5) (RV-A), 1.4 × 10(3) (HAdV), 8.1 × 10(2) (NoV GII) and 2.8 × 10(4) (HAV). Data on viral detection in treated effluents of hospital WWTPs confirmed the potential for environmental contamination by viruses and could be useful to establish standards for policies on wastewater management.

Detection of rotavirus A in sewage samples using multiplex qPCR and an evaluation of the ultracentrifugation and adsorption-elution methods for virus concentration

Group A rotaviruses (RV-A) are the most common agents of viral gastroenteritis in children worldwide. The goal of this study was to compare two different methods to concentrate RV-A from sewage samples and to improve the detection and quantification of RV-A using a multiplex quantitative PCR assay with an internal control. Both RV-A and the internal control virus, bacteriophage PP7, were seeded into wastewater and then concentrated using either an ultrafiltration-based adsorption-elution protocol or an ultracentrifugation-based protocol. Real time multiplex quantitative PCR was used to quantify the purified RV-A and PP7, and the results of the multiplex assay were compared with the results of the monoplex assays. The ultracentrifugation-based method had a mean recovery rate of 47% (range: 34-60%), while the ultrafiltration-based adsorption-elution method had a mean recovery rate of 3.5% (range: 1.5-5.5%). These results demonstrate that ultracentrifugation is a more appropriate method for recovering RV-A from wastewater. This method together with the multiplex qPCR assay may be suitable for routine laboratory use.