Environmental surveillance. An additional/alternative approach for virological surveillance in Greece?

Hepatitis A virus monitoring in wastewater: A complementary tool to clinical surveillance

Monitoring wastewater is an effective tool for tracking information on trends of enteric viral dissemination. This study aimed to perform molecular detection and genetic characterization of HAV in wastewater and to correlate the results with those obtained from clinical surveillance. Wastewater samples (n=811) of the second most populous city in Argentina were collected from the main wastewater treatment plant (BG-WWTP, n=261), and at 7 local neighborhood collector sewers (LNCS, n=550) during 2017-2022. Clinical samples of acute hepatitis A cases (HA, n=54) were also analyzed. HAV molecular detection was performed by real time RT-PCR, and genetic characterization by RT-Nested PCR, sequencing and phylogenetic analysis. RNA-HAV was detected in sewage samples throughout the entire period studied, and detection frequencies varied according to the location and year (2.9% - 56.5%). In BG-WWTP, 23% of the samples were RNA-HAV+. The highest detection rates were in 2017 (30.0%), 2018 (41.7%) and 2022 (56.5%), which coincides with the highest number of HA cases reported. Twenty-eight (28) sequences were obtained (from clinical and sewage samples), and all were genotype IA. Two monophyletic clusters were identified: one that grouped clinical and wastewater samples from 2017-2018, and another with specimens from 2022, evidencing that environmental surveillance might constitute a replica of viral circulation in the population. These findings evidence that WBE, in a centralized and decentralized sewage monitoring, might be an effective strategy to track HAV circulation trends over time, contributing to the knowledge of HAV in the new post-vaccination epidemiological scenarios in Argentina and in Latin America.

Occurrence of Hepatitis A Virus in Water Matrices: A Systematic Review and Meta-Analysis

Hepatitis A is a common form of viral hepatitis. It is usually transmitted through the ingestion of contaminated food and water. This systematic review was carried out to summarise the overall prevalence of Hepatitis A virus (HAV) in different water matrices: untreated and treated wastewater, surface water, groundwater, drinking water, and others (e.g., irrigation water and floodwater). The literature search was performed in four databases: PubMed, Web of Science, Global Index Medicus, and Excerpta Medica Database. Heterogeneity (I2) was assessed using the χ2 test on the Cochran Q statistic and H parameters. A total of 200 prevalence data from 144 articles were included in this meta-analysis. The overall prevalence of HAV in water matrices was 16.7% (95% CI: 13.4−20.3). The prevalence for individual matrix was as follows: 31.4% (95% CI: 23.0−40.4) untreated wastewater, 18.0% (95% CI: 9.5−28.2) treated wastewater, 15.0% (95% CI: 10.1−20.5) surface water, 2.3% (95% CI: 0.1−6.0) in groundwater, 0.3% (95% CI: 0.0−1.7) in drinking water, and 8.5% (95% CI: 3.1−15.6) in other matrices. The prevalence was higher in low-income economies (29.0%). Africa and Eastern Mediterranean were the regions with higher HAV prevalence values. This study showed a high heterogeneity (I2 > 75%) with a significant publication bias (p value Egger test < 0.001). The results of this review suggest that water matrices could be an important route of HAV transmission even in industrialized countries, despite the lower prevalence compared to less industrialized countries, and the availability of advanced water management systems. More effective water/wastewater treatment strategies are needed in developing countries to limit the environmental circulation of HAV.

Hepatitis E Virus in Water Environments: A Systematic Review and Meta-analysis

Hepatitis E virus (HEV) is responsible for acute hepatitis in humans, through foodborne, zoonotic, and waterborne transmission routes. This study aimed to assess the prevalence of HEV in water matrices. Six categories were defined: untreated and treated wastewater, surface water (river, lake, and seawater), drinking water, groundwater, and other water environments (irrigation water, grey water, reservoir water, flood water, and effluent of pig slaughterhouse). We searched PubMed, Web of Science, Global Index Medicus, and Excerpta Medica Database. Study selection and data extraction were performed by at least two independent investigators. Heterogeneity (I²) was assessed using the χ² test on the Cochran Q statistic and H parameter. Sources of heterogeneity were explored by subgroup analysis. This study is registered with PROSPERO, number CRD42021289116. We included 87 prevalence studies from 58 papers, 66.4% of which performed in Europe. The overall prevalence of HEV in water was 9.8% (95% CI 6.4-13.7). The prevalence was higher in untreated wastewater (15.1%) and lower in treated wastewater (3.8%) and in drinking water (4.7%). In surface water, prevalence was 7.4%, and in groundwater, the percentage of positive samples, from only one study available, was 8.3%. Overall, only 36.8% of the studies reported the genotype of HEV, with genotype 3 (HEV-3) prevalent (168 samples), followed by HEV-1 (148 sample), and HEV-4 (2 samples). High-income countries were the most represented with 59/87 studies (67.8%), while only 3/87 (3.5%) of the studies were performed in low-income countries. The overall prevalence obtained of this study was generally higher in industrialized countries. Risk of bias was low in 14.9% of the studies and moderate in 85.1%. The results of this review showed the occurrence of HEV in different waters environments also in industrialized countries with sanitation and safe water supplies. While HEV transmission to humans through water has been widely demonstrated in developing countries, it is an issue still pending in industrialized countries. Better knowledge on the source of pollution, occurrence, survival in water, and removal by water treatment is needed to unravel this transmission path.

Human Polyomaviruses (HPyV) in Wastewater and Environmental Samples from the Lisbon Metropolitan Area: Detection and Genetic Characterization of Viral Structural Protein-Coding Sequences

Due to the lack of reliable epidemiological information regarding the geographic distribution and genetic diversity of human polyomaviruses (HPyV) in Portugal, we addressed these issues in this initial study by focusing on the Lisbon Metropolitan area, the most populated and culturally diverse hub in the country. The HPyV structural protein-coding sequence was partially amplified using two touch-down PCR multiplex protocols, starting from water samples, collected between 2018 and 2020, where viral genomes were detected. The obtained results disclosed the frequent detection of HPyV1, HPyV2, HPyV5, and HPyV6 in 35.3% (n = 6), 29.4% (n = 5), 47.1% (n = 8) and 29.4% (n = 5), respectively, of the water samples analyzed. The sequences assigned to a given viral species did not segregate to a single genotype, this being especially true for HPyV2 for which five genotypes (including a putative new genotype 9) could be identified. The phylogenetic trees obtained for HPyV5 and HPyV6 had less resolving power than those obtained for HPyV1/HPyV2, but both viruses were shown to be genetically diverse. This analysis emphasizes the epidemiological helpfulness of these detection/genetic characterization studies in addition to being relevant tools for assessment of human waste contamination.

Coronavirus: occurrence, surveillance, and persistence in wastewater

The coronavirus disease (COVID-19) outbreak reported in China in December 2019 has spread throughout the world. The WHO declared it as a pandemic in March 2020. The pandemic severely affected public health and the global economy. Many studies conducted on the coronavirus have helped us to elucidate its pathogenicity and pathophysiology. However, it is important to study the behavior of the pathogen in the environment to develop effective control measures. While studying the persistence and transmission of viruses in drinking water and wastewater systems, a low concentration of coronavirus and its nucleic acids have been detected in municipal wastewaters. This could be due to their high susceptibilities to degradation in aqueous environments. Epidemiological study on coronaviruses in wastewater will serve two purposes, i.e., in early detection of outbreak and in identifying asymptomatic carriers. In such cases, the epidemiological study will help in early detection of the presence of the virus in the community. Secondly, it will help in knowing if there are asymptomatic carriers, as such people do not show any signs of symptoms but shed the viruses in feces. The present review focuses on the epidemiological surveillance of wastewater for coronaviruses, as in recent years these are increasingly causing global pandemics. In this review we have discussed, the four pertinent areas of coronavirus study: (1) occurrence of coronavirus in wastewater, (2) wastewater based epidemiological surveillance of coronaviruses, (3) epidemiological surveillance tools used for detection of coronaviruses in sewage, and (4) persistence and sustainability of coronaviruses in wastewater.

Assessment of enteric viruses during a hepatitis outbreak in Detroit MI using wastewater surveillance and metagenomic analysis

AIMS

This study investigates enteric viruses in wastewater during an outbreak of acute hepatitis caused by hepatitis A virus (HAV) in a large metropolitan area. Emphasis is given to caliciviruses and HAV.

METHODS AND RESULTS

Metagenomic analysis was performed to characterize enteric viruses excreted by the population of Detroit MI, during a hepatitis A outbreak that occurred in 2017 and 2018. Additionally, HAV, norovirus GII, and sapovirus were quantified, using qPCR, in 54 untreated wastewater samples collected over the course of 4 months. Correlation analysis was performed to identify associations between the number of disease cases and HAV concentrations in wastewater. HAV obtained the highest relative abundance among other enteric viruses detected in wastewater metagenomes. Metagenomic analysis also detected several other enteric viruses including astrovirus, enterovirus and hepatitis E virus. Average sapovirus concentrations of 1·36 × 10⁶  gc l^-1 were significantly greater than norovirus GII concentrations (2·94 × 10⁴  gc l^-1 ). Additionally, norovirus GI and GII along with sapovirus GI.1 were detected using metagenomics. HAV loads in wastewater were significantly correlated with the number of disease cases reported 1 week after wastewater sampling.

CONCLUSIONS

Surveying untreated wastewater is a promising method for detecting early signs of hepatitis A outbreaks and for routine environmental monitoring of enteric viruses circulating in the environment.

SIGNIFICANCE AND IMPACT OF THE STUDY

Authors demonstrate the usefulness of metagenomics for genogrouping and enteric viral surveillance.

The Effectiveness of Activated Sludge Procedure and UV-C254 in Norovirus Inactivation in a Tunisian Industrial Wastewater Treatment Plant

The molecular detection of Norovirus GI and Norovirus GII in the Tunisian industrial wastewater treatment plant of Charguia I was conducted to test the effectiveness of secondary biological treatment using the activated sludge procedure and the UV-C₂₅₄ tertiary treatment radiation using a UV disinfection prototype to upgrade the quality of the purified wastewater. A total of 140 sewage samples were collected from the two lines of sewage treatment procedures. Norovirus GI and Norovirus GII have been found and quantified using Real-Time Reverse Transcription Polymerase Chain Reaction (qRT-PCR) in 66.4 and 86.4% of the collected wastewater samples. The Norovirus GI and GII mean concentration values got in the treated effluents showed a significant decrease of Norovirus viral content rates detected from upstream to downstream of activated sludge procedures and at the output of UV-C₂₅₄ treatment. These findings characterise and denote for the first time the effectiveness of biological and UV-C254 treatment for Norovirus GI and Norovirus GII removal in Tunis City, northern Tunisia. Also, these data underlined the fact that purified sewage makes up a route of gastroenteritis virus transmission and a cause of viral gastroenteritis associated with water-borne and food-borne outbreaks.

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

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

Epidemiology of hepatitis E in South-East Europe in the "One Health" concept

The significance of hepatitis E virus (HEV) as an important public health problem is rising. Until a decade ago, cases of HEV infection in Eur-ope were mainly confined to returning travelers, but nowadays, hepatitis E represents an emerging zoonotic infection in many European countries. The aim of this manuscript is to perform a systematic review of the published literature on hepatitis E distribution in humans, animals and environmental samples ("One Health" concept) in the South-Eastern European countries. Comparison of the available data showed that the anti-HEV seroprevalence in the South-Eastern Europe varies greatly, depending on the population studied, geographical area and methods used. The IgG seroprevalence rates in different population groups were found to be 1.1%-24.5% in Croatia, up to 20.9% in Bulgaria, 5.9-%17.1% in Romania, 15% in Serbia, up to 9.7% in Greece and 2%-9.7% in Albania. Among possible risk factors, older age was the most significant predictor for HEV seropositivity in most studies. Higher seroprevalence rates were found in animals. HEV IgG antibodies in domestic pigs were detected in 20%-54.5%, 29.2%-50%, 38.94%-50% and 31.1%-91.7% in Serbia, Bulgaria, Romania and Croatia, respectively. In wild boars seroprevalence rates were up to 10.3%, 30.3% and 31.1% in Romania, Slovenia and Croatia, respectively. A high HEV RNA prevalence in wild boars in some countries (Croatia and Romania) indicated that wild boars may have a key role in the HEV epidemiology. There are very few data on HEV prevalence in environmental samples. HEV RNA was detected in 3.3% and 16.7% surface waters in Slovenia and Serbia, respectively. There is no evidence of HEV RNA in sewage systems in this region. The available data on genetic characterization show that human, animal and environmental HEV strains mainly belong to the genotype 3.

Assessment of the Virological Quality of Marine and Running Surface Waters in NW Greece: A Case Study

The virological quality of surface marine and running water samples collected from Igoumenitsa gulf and Kalamas river (NW Greece) was assessed from October 2012 to September 2013. Sampling sites were exposed to different land and/or anthropogenic effects. Seawater samples were collected monthly from five sampling stations (new harbor, old harbor, wastewater treatment plant outlet, protected Natura area, Drepano beach). Viral targets included human adenoviruses (hAdVs), as index human viruses, while noroviruses (NoVs) and hepatitis A virus (HAV) were also studied. Kalamas river samples were collected seasonally, from three sampling stations (Soulopoulo, Dam, Sagiada-estuaries), while viral targets included also porcine adenoviruses (pAdVs) and bovine polyoma viruses (bPyVs), as additional index viruses. All water samples were analyzed for standard bacterial indicators, as well. Physicochemical and meteorological data were also collected. Based on the standard bacterial indices, both sea and river water samples did not exceed the limits set according to Directive 2006/7/EU. However, positive samples for hAdVs were found occasionally in all sampling sites in Igoumenitsa gulf (23.3%, 14/60) showing fecal contamination of human origin. Moreover, HAV was detected once, in the sampling site of the old port (at 510 GC/L). Most of the Kalamas water samples were found positive for hAdVs (58.3%, 7/12), while human noroviruses GI (NoVGI) (8.3%, 1/12) and GII (NoVGII) (16.7%, 2/12) were also detected. HAV, pAdVs, and bovine polyomaviruses (bPyVs) were not detected in any of the analyzed samples. No statistically significant correlations were found between classic bacterial indicators and viral targets, nor between viruses and meteorological data. Overall, the present study contributed to the collection of useful data for the biomonitoring of the region, and the assessment of the overall impact of anthropogenic activities. It provided also valuable information for the evaluation of the risk of waterborne viral infections and the protection of public health. It was the first virological study in the area and one of the few in Greece.

Measuring biomarkers in wastewater as a new source of epidemiological information: Current state and future perspectives

The information obtained from the chemical analysis of specific human excretion products (biomarkers) in urban wastewater can be used to estimate the exposure or consumption of the population under investigation to a defined substance. A proper biomarker can provide relevant information about lifestyle habits, health and wellbeing, but its selection is not an easy task as it should fulfil several specific requirements in order to be successfully employed. This paper aims to summarize the current knowledge related to the most relevant biomarkers used so far. In addition, some potential wastewater biomarkers that could be used for future applications were evaluated. For this purpose, representative chemical classes have been chosen and grouped in four main categories: (i) those that provide estimates of lifestyle factors and substance use, (ii) those used to estimate the exposure to toxicants present in the environment and food, (iii) those that have the potential to provide information about public health and illness and (iv) those used to estimate the population size. To facilitate the evaluation of the eligibility of a compound as a biomarker, information, when available, on stability in urine and wastewater and pharmacokinetic data (i.e. metabolism and urinary excretion profile) has been reviewed. Finally, several needs and recommendations for future research are proposed.

Performance of three small-scale wastewater treatment plants. A challenge for possible re use

The study focused on the assessment of the performance of three WWTPs in Greece by the estimation of the microbiological and chemical quality of influent and effluent sewage. Physicochemical parameters were recorded (temperature, pH, COD, BOD, suspended solids, conductivity), and meteorological data were collected (air temperature, rain). Microbiological parameters were analyzed (Escherichia coli, total coliforms, bacteriophages, Salmonella, human adenoviruses, Candida, Pseudallescheria boydii, helminths, parasites Cryptosporidium ssp., and Giardia spp.). Statistically significant correlations among the various aforementioned parameters were investigated, in an attempt to propose appropriate processing performance indicators. Furthermore, the study aimed to assess current joint ministerial decision (JMD) on wastewater reuse, for irrigation purposes; to evaluate its practicability and its potential for public health protection. In the vast majority, outlet samples from all three studied WWTPs were not appropriate for irrigation reuse purposes based on BOD50 and suspended solids limit values, set by the current JMD, for both limited and unrestricted irrigation applications. Reductions for E. coli, total coliforms, and bacteriophages were found to range between 2-3, 1.5-2.5, and 2-4 log10 values, respectively. Salmonella spp. was detected in outlet sewage samples from Patra (PAT), Arachova (ARH), and Livadeia (LEV), at 23% (3/13), 33% (4/12), and 38% (5/13), respectively. Molds were detected at 92.3% (12/13), 100% (13/13), and 91.6% (11/12), respectively, while Candida was found at 85% (11/13), 67% (8/12), and 46% (6/13). A high prevalence of Pseudallescheria boydii, in outlet samples from all studied WWTPs is an important public health issue, which underlines the need for further studies on this emerging fungal pathogen in wastewater reuse applications. Pseudallescheria boydii was found at 85% (11/13), 67% (8/12), and 46% (6/13), respectively. Helminths were found in both inlet and outlet samples, of all studied WWTPs, at 100%. Human adenoviruses, were detected at high percentages in outlet samples at 76.9% (10/13), 92.3% (12/13), 84.6% (11/13), respectively, while no influence of UV irradiation was recorded on the entry and exit loads of human adenoviruses. No influence of meteorological parameters was found on the microbiological and chemical parameters, with the exception of a weak positive correlation between environmental temperature and bacteriophages. A moderate positive correlation was found between BOD and suspended solids, bacteriophages, and total coliforms, bacteriophages and E. coli, and bacteriophages and adenoviruses. A significant positive correlation was found between total coliforms and E. coli, COD and BOD, and suspended solids and COD. No correlations were proved between human pathogens and bacterial indicator parameters. Collectively, our findings underlined the unsuitability of the current JMD on wastewater reuse in Greece, or public health protection. The study is expected to support the development of a public health risk assessment model based on quantitative risk assessment on the use of treated wastewater for irrigation purposes in Greece.

First detection of hepatitis E virus in Central Argentina: environmental and serological survey

BACKGROUND

The hepatitis E virus (HEV) is an emergent causative agent of acute hepatitis worldwide, transmitted by fecal-oral route. In Argentina it is considered rare, so differential laboratory testing is not routinely performed. Besides, in Argentina's central area epidemiological and molecular characteristics of HEV are still unknown.

OBJECTIVES

Provide evidence of local circulation of HEV by molecular detection on environmental samples and by serological survey in healthy adult population of Córdoba city, Argentina.

STUDY DESIGN

Environmental surveillance was conducted in river and sewage samples collected between 2007 and 2009-2011. Viral detection was performed by RT-Nested PCR of ORF-1 and ORF-2 partial regions. Anti-HEV IgG was determined by EIA in 433 serum samples collected between 2009 and 2010.

RESULTS

HEV was detected in 6.3% of raw sewage samples and in 3.2% of riverine samples. Nucleotide sequencing analyses revealed that all isolates belonged to genotype 3, subtypes a, b and c. The prevalence of IgG anti-HEV was 4.4%. Seroprevalence increased with the age of the individuals (OR: 3.50; 95% CI 1.39-8.87; p=0.0065) and, although the prevalence was higher in low income population, no statistical relation was found between anti-HEV and socioeconomic level.

CONCLUSIONS

The environmental findings added to serological results, demonstrate that HEV circulates in central Argentina. Contamination of water with HEV could represent a route of transmission for local populations, which have a high number of susceptible individuals. This fact alerts local health care systems in order to include detection of HEV in the diagnostic algorithm of viral hepatitis.

Evidence of hepatitis A virus circulation in central Argentina: seroprevalence and environmental surveillance

BACKGROUND

Hepatitis A virus (HAV) has shown intermediate endemicity in Argentina, but notification of clinical cases has decreased since the introduction of the vaccine in 2005.

OBJECTIVES

In order to get insight into the local circulation of this virus after four years of the official introduction of the vaccine, the aims of this study were to provide information on HAV immune status of the adult population of Córdoba city and to conduct environmental surveillance of HAV in sewage and river samples in the same region.

STUDY DESIGN

The prevalence of anti-HAV was determined by EIA in 416 samples of people (without prior vaccination) from Córdoba city (2009-2010). Spline regression models were estimated under generalized additive models. Environmental surveillance was conducted in river and sewage samples collected in the same period. Viral detection was performed by RT-Nested PCR of the 5'UTR.

RESULTS

In Córdoba, the global prevalence of anti-HAV was 73.5%. It increased with age (p<0.0001) and it was associated with the low-income population (OR: 1.14; 95% CI 1.05-1.25). This prevalence decreased in younger age groups, especially in the high-income population. Environmental monitoring revealed the presence of HAV (IA) in 20.8% and 16.1% of wastewater and river samples, respectively.

CONCLUSIONS

As a consequence of a decrease in HAV circulation due to improvements in immunization, socio-economic and hygienic conditions, young adults are becoming increasingly susceptible to HAV infections. Environmental monitoring demonstrated that HAV circulates in the local population; therefore, health care systems should consider the implementation of preventive measures for susceptible adults in order to reduce the risk of HAV infection.

Epidemiological investigation of two parallel gastroenteritis outbreaks in school settings

BACKGROUND

Two parallel gastroenteritis outbreaks occurred in an elementary school and a neighboring kindergarten in Kilkis, Northern Greece in 2012. The aim of the study was the investigation of these two parallel outbreaks as well as their possible source.

METHODS

Two retrospective cohort studies were performed to identify the mode and the vehicle of transmission as well as the possible connection between them.

RESULTS

Elementary school and kindergarten populations of 79.9% (119/149) and 51.1% (23/45) respectively, participated in the study. Case definition was satisfied by 65 pupils from the elementary school and 14 from the kindergarten. For elementary school, 53 cases were considered primary cases of the outbreak and were included in the analysis. Based on the results of the multivariate analysis, consumption of tap water was the only statistically significant independent risk factor of gastroenteritis (RR = 2.34, 95% C.I.: 1.55-3.53).; a finding supported by the shape of the epidemic curve which referred to a common point source outbreak with secondary cases. For kindergarten, no statistically significant risk factor was identified, and the epidemic curve supported a person-to-person transmission according univariate analysis. Norovirus GI and GII and human Adenovirus were detected by Real Time PCR in stool samples from seven children of elementary school, but stool samples were not collected by children of the kindergarten.

CONCLUSIONS

Even though the etiological agent of the outbreak was not verified, combined epidemiological and laboratory results were in favor of a waterborne viral gastroenteritis outbreak at the elementary school, followed by a person to person spread at the kindergarten.

Genetic diversity and molecular characterization of enteroviruses from sewage-polluted urban and rural rivers in the Philippines

Despite the vast distribution and expansive diversity of enteroviruses reported globally, indicators defining a complete view of the epidemiology of enteroviruses in tropical countries such as the Philippines are yet to be established. Detection of enteroviruses in the environment has been one of the markers of circulating viruses in a community. This study aimed to bridge the gap in the epidemiology of enteroviruses in the Philippines by providing an overview of the occurrence of enteroviruses in both urban and rural rivers. Molecular detection directed at the VP1 region of the enterovirus genome was performed on 44 grab river water samples collected from April to December 2009. The majority of the enterovirus serotypes detected were clustered with human enterovirus C species (HEV-C; 21/42), followed by HEV-B (12/42) and HEV-A (9/42). Porcine enterovirus 9 was also found in 12 out of 44 water samples. Phylogenetic analysis indicated that the viruses detected were closely related, if not all forming a monophyletic clade, with those enteroviruses detected previously from acute flaccid paralysis cases in the country. The clustering of environmental and human enterovirus strains implies that the circulation of these strains were associated with river contamination. This study gives further evidence of the environmental persistence of enteroviruses once they are shed in feces and likewise, provides additional data which may help in understanding the epidemiology of enteroviruses in humans, highlighting the need for more studies on the potential public health risks linked with enteroviruses found in the environment and their eventual clinical consequences in the country.