Integrated hepatitis e virus monitoring in central Argentina: a six-year analysis of clinical surveillance and wastewater-based epidemiology.

Wastewater-based epidemiology (WBE) has gained prominence worldwide as a powerful tool in public health. This study aimed to monitor the circulation of Hepatitis E Virus (HEV) from wastewater samples collected during a six-year period and compare these results with clinical surveillance in the central region of Argentina. From 2017 to 2022, 1008 raw wastewater samples were analyzed, including four wastewater treatment plants from four cities (n=319), and 7 local neighborhood collector sewers in Córdoba city (n=689). Serum and/or stool samples from patients suspected of HEV infection were also analyzed (n=48). HEV molecular detection and viral load quantification were performed by real time RT-qPCR, and genetic characterization by two RT-Nested PCRs (targeting partial ORF-1 and ORF-2 genomic regions), sequencing and phylogenetic analysis. Fifty-three (5.3%) wastewater samples were RNA-HEV positive by real time RT-qPCR, with variations according to the location and year (0.0% - 21.6%). Out of these, ORF-2 genomic region was amplified in 20 samples (37.7%) and ORF-1 partial region in 12 (22.6%), and eighteen sequences were obtained. Throughout the study period, two (4.2%) HEV confirmed infections were reported, and one sequence was obtained. Phylogenetic analyses for both genomic regions showed that all the isolates were genotype HEV-3 clade abchijklm. Our study detected HEV in wastewater over a six-year period, despite a low number of clinical cases, emphasizing WBE as a valuable tool that complements clinical surveillance, by detecting pathogens' presence; identifying their transmission, circulation dynamics and excretion hotspots; and revealing changes in their genomic diversity.

High circulation of hepatitis E virus (HEV) in pigs from the central region of Argentina without evidence of virus occurrence in pork meat and derived products.

Hepatitis E virus (HEV) is an emerging cause of viral hepatitis and pigs are considered a reservoir for the virus. HEV genotype 3 (HEV-3) has been reported in pigs, environmental matrices, and sporadic human cases in Argentina. We aimed to investigate HEV circulation in pigs from central Argentina and to assess the virus presence in pork meat and food products. Four types of samples obtained or derived from pigs collected in Córdoba province (Argentina) between 2019 and 2022, were tested: 276 serum samples were analyzed for anti-HEV antibody detection; stool (n = 20), pork meat (n = 71), and salami (n = 76) samples were studied for RNA-HEV detection, followed by sequencing and phylogenetic analyses. The positivity rate for anti-HEV antibodies was 80.1% (221/276). Eleven fecal samples (11/20) tested positive for RNA-HEV, from animals under 120 days of age. Three samples could be sequenced, and phylogenetic analyses revealed that they belonged to HEV-3 clade abchijklm, clustering close to strains previously detected in wastewater from Córdoba. None of the muscle meat or salami samples tested positive. A high HEV circulation in pigs was found, showing that these animals may play a significant role in the viral maintenance in the region, becoming a potential risk to the exposed population. Despite not detecting RNA-HEV in pork meat and salami in our study, we cannot rule out the possibility of foodborne transmission in Córdoba province.

[Evaluation of surface water quality in recreational areas, an integrative proposal of chemical and microbiological markers]. / Evaluación de la calidad de aguas superficiales en espacios recreacionales , una propuesta integradora de marcadores químicos y microbiológicos.

Climate change affects the interactions between water systems, ecosystems, and the atmosphere. It also increases the risk of the presence of microorganisms which affect the systems that use these resources. The impact of the population on the water resources has become more evident in recent years, highlighting the close relationship between the levels of inorganic components and microbiological contamination of water and community health. The characterization of the variables that account for water pollution is a complex process. In this paper, it is proposed to quantified nitrites and phosphorous as chemical markers and fecal coliforms, genomic human adenovirus and/or picobirnavirus and infectious human enterovirus detection as microbiological markers for the prevention of water-borne infections in individuals exposed to superficial aqueous matrices by recreational activities.

El cambio climático afecta a las interacciones entre los sistemas hídricos, los ecosistemas y la atmósfera. También aumenta el riesgo de la presencia de microorganismos que afectan a los sistemas que utilizan estos recursos. El impacto de la población sobre los recursos hídricos se ha hecho más evidente en los últimos años, destacando la estrecha relación entre los niveles de componentes inorgánicos así como la contaminación microbiológica del agua y la salud de la comunidad. La caracterización de las variables que dan cuenta de la contaminación del agua es un proceso complejo. En este trabajo se propone la cuantificación de nitritos y fósforo como marcadores químicos y la detección de coliformes fecales, adenovirus humanos genómicos y/o picobirnavirus y enterovirus humanos infecciosos como marcadores microbiológicos para la prevención de infecciones de origen hídrico en individuos expuestos a matrices acuosas superficiales por actividades recreativas.

Wastewater based epidemiology as a silent sentinel of the trend of SARS-CoV-2 circulation in the community in central Argentina.

Monitoring wastewater for the traces of viruses allows effective surveillance of entire communities, including symptomatic and asymptomatic infected individuals, providing information on whether a specific pathogen is circulating in a population. In the context of the COVID-19 pandemic, 261 wastewater samples from six communities of the province of Córdoba, Argentina were analyzed. From mid-May 2020 to the end of August 2021, raw sewage samples were collected from the central network pipe that enters into the Wastewater Treatment Plants (WWTP) in Córdoba city and five communities in the Punilla Valley. SARS-CoV-2 was concentrated by using the polyethylene glycol-6000 precipitation method. Viral genomes were extracted from concentrated samples, and N- and E-SARS-CoV-2 genes were detected by using real time RT-PCR. Wastewater samples that resulted positive for SARS-CoV-2 genome detection were subjected to viral variants of concern (VOCs) identification by real time RT-PCR. Overall, just by using the identification of the N gene or E gene, the rates of viral genome detection were 43.4% (86/198) and 51.5% (102/198) respectively, and by using both methodologies (positivity criterion: detection of N and / or E gene), the detection rate was 71.2% (141/198). Thereby, the optimal strategy to study the SARS-CoV-2 genome in wastewater would be the use of the combined detection of both genes. Detection of SARS-CoV-2 variants in wastewater reflected their circulation in the community, showing no VOCs detection in the first COVID-19 wave and their co-circulation with Gamma, Alpha and Delta VOCs during 2021. Therefore, SARS-CoV-2 Wastewater Based Epidemiology (WBE) described the introduction, permanence and/or the co-circulation of viral variants in the community. In geographical areas with a stable population, SARS-CoV-2 WBE could be used as an early warning sign of new COVID-19 cases, whereas in localities with a low number of inhabitants and high tourist influx, WBE may only be useful to reflect the circulation of the virus in the community. Overall, the monitoring of SARS-CoV-2 in wastewater can become a silent sentinel of the trend of viral circulation in the community, providing supplementary information for clinical surveillance to support public health measures.

Rotavirus contamination of surface waters from the northwest of Argentina.

Fecal pollution of water is a serious concern because it is associated with the transmission of pathogens. The aim of this study was to analyze the occurrence of group A rotavirus (RVA) in surface waters from the Arias-Arenales River in Salta, a northern city in Argentina, and to define possible sources of fecal viral pollution. A total of 116 water samples were analyzed and RVA was detected in 3.4% (95% CI: 0.1-7.0%), with concentrations ranging from 1.9 × 105 to 3.8 × 106 genome copies per liter. RVA strains were characterized as G1P[8], G4P[8] and G9P[8], which are common genotypes circulating in the local population. The Arias-Arenales River presented unusual and sporadic contamination by RVA, originated from stormwater discharges and a variety of non-identified sources, and support the essential need of viral indicators for enhanced monitoring of water quality.

Searching variables to assess recreational water quality: the presence of infectious human enterovirus and its correlation with the main variables of water pollution by multivariate statistical approach in Córdoba, Argentina.

Surface waters are used by local populations for different purposes, such as recreational activities, water source for human and animal consumption, and irrigation among others, which lead to the need for management strategies on water health and associated risks. During this study, we investigated physicochemical parameters, fecal coliform bacteria, and infectious human enterovirus detection to determine the water quality in different beaches (categorized as an urban area, non-urban areas, and an intermediate position) from San Roque Dam, in Argentina. Multivariate techniques were applied. Principal component analysis allowed identification of subgroup of variables responsible for the water quality. A cluster analysis and multivariate analysis of variance showed the urban beach as the highest pollution area. The following variables (measured at the urban beach) would be enough to describe the quality of the aquatic body: nitrites, fecal coliforms, total phosphorous, and infectious human enterovirus. The infectious human enterovirus was an independent variable detected in 69.1% of the samples showing a steady frequency of detection during the whole period studied and could identify human fecal contaminations as a source of water pollution. The selected variables would contribute to water quality regarding the risk for human health using San Roque dam waters for recreational propose.

Evaluation of concentration efficiency of the Pseudomonas aeruginosa phage PP7 in various water matrixes by different methods.

Enteric viruses monitoring in surface waters requires the concentration of viruses before detection assays. The aim of this study was to evaluate different methods in terms of recovery efficiencies of bacteriophage PP7 of Pseudomonas aeruginosa, measured by real-time PCR, using it as a viral control process in water analysis. Different nucleic acid extraction methods (silica-guanidinium thiocyanate, a commercial kit (Qiagen Viral RNA Kit) and phenol-chloroform with alcohol precipitation) exhibited very low recovery efficiencies (0.08-4.18 %), being the most efficient the commercial kit used for subsequent experiments. To evaluate the efficiency of three concentration methods, PBS (as model for clean water) and water samples from rivers were seeded to reach high (HC, 10(6) pfu ml(-1)) and low concentrations (LC, 10(4) pfu ml(-1)) of PP7. Tangential ultrafiltration proved to be more efficient (50.36 ± 12.91, 17.21 ± 9.22 and 12.58 ± 2.35 % for HC in PBS and two river samples, respectively) than adsorption-elution with negatively charged membranes (1.00 ± 1.34, 2.79 ± 2.62 and 0.05 ± 0.08 % for HC in PBS and two river samples, respectively) and polyethylene glycol precipitation (15.95 ± 7.43, 4.01 ± 1.12 and 3.91 ± 0.54 %, for HC in PBS and two river samples, respectively), being 3.2-50.4 times more efficient than the others for PBS and 2.7-252 times for river samples. Efficiencies also depended on the initial virus concentration and aqueous matrixes composition. In consequence, the incorporation of an internal standard like PP7 along the process is useful as a control of the water concentration procedure, the nucleic acid extraction, the presence of inhibitors and the variability of the recovery among replicas, and for the calculation of the sample limit of detection. Thus, the use of a process control, as presented here, is crucial for the accurate quantification of viral contamination.

HHV-6 IgG4 isotype response following measles infection.

Human herpesvirus 6 (HHV-6) is widespread in the human population by infecting most individuals in early childhood. After primary infection, HHV-6 establishes a latent infection by remaining in circulating mononuclear cells of healthy individuals. The HHV-6 antibody titer increases after primary infection with measles virus. The present study was undertaken to determine the specific antiviral IgG1, IgG2, IgG3, and IgG4 subclass response patterns to HHV-6 in HHV-6-seropositive individuals with natural measles virus infection, measles vaccination, and rubella virus infection. The purpose of this study was to examine HHV-6-specific IgG isotype response in patients with acute virus coinfection. Serum samples were obtained from individuals who were seropositive for HHV-6 after natural primary infection with measles virus during an outbreak, measles vaccination, or rubella virus infection, and from healthy individuals. Sera were examined by indirect immunofluorescence assays for detection of HHV-6-specific IgG1, IgG2, IgG3, and IgG4 antibodies. A high percentage (69%) of those infected with measles virus had an HHV-6 IgG1 and IgG4 response (P < 0.001, chi(2) test), whereas persons vaccinated against measles, those infected with rubella, and healthy individuals showed an HHV-6 IgG1 response. These results demonstrate that natural measles virus infection induces an HHV-6 IgG isotype response, which suggests a shift in immune activity from a Th1 to a Th2 response. J. Med. Virol. 82:396-399, 2010. (c) 2010 Wiley-Liss, Inc.

Loss of maternally-derived human herpesvirus-7 immunity and natural infection in Argentinian infants.

BACKGROUND: Human herpes virus-7 (HHV-7) infection is widespread throughout the world. No data are available in Argentina about loss of maternally-derived HHV-7 immunity and natural infection. OBJECTIVES: The objective of this study was to characterize the time when children lose maternal antibodies and become susceptible to natural infection. METHODS: Sera from 39 pregnant women and 207 infants between 2 and 29 months of age were tested. Determination of IgG antibodies was made by indirect immunofluorescence. RESULTS: The seropositive ratio fell in the 2-4 month group (15% seropositive) and increased between 5 months (47% seropositive) and 23 months (67%). Geometric mean titers (GMT) of the infants aged 2-4 months (GMT = 60) were statistically different (p < 0.0001, Student's t-test) to those from the group of pregnant women (GMT = 83) and those from the other infant groups (p < 0.001, least significant difference (LSD) test). The GMT of the groups between 5 and 23 months did not show significant differences whereas those of infants between 24 and 29 months (GMT = 179, 79% seropositive) were different from all the groups studied (p < 0.0001, LSD test). CONCLUSIONS: This study shows a significant association between the loss of passive HHV-7 antibody and age. HHV-7 enters the susceptible population at 5 months, leading to the high prevalence of antibodies between 24 and 29 months of age. This study also shows that natural infection by HHV-7 in children during their first years of life follows the infection pattern found in developing countries.

Características morfológicas de placas producidas por el virus rubéola en cultivos de células Vero / Morphological characteristics of rubella virus plaques in Vero cell cultures

Bajo condiciones definidas de plaqueo, la cepa Gilschrist de virus rubeola mostró diferencias en la morfología y tamaño de placas en cultivos de células Vero. Estas diferencias se obtuvieron cambiando la concentración de suero fetal bovino. Cuando se utilizó 2% de suero, las placas formadas fueron definidas, mostrando células dispersas que retienen el colorante. En cambio, se formaron placas en forma de anillo cuando la concentración de suero fetal bovino fue modificada al 4%. Esta característica permanece constante después de varios pasajes de la cepa de virus en células Vero. Por ensayos comparativos se determinó la posibilidad de utilizar el efecto citopático en la titulación de virus rubeola, el que brindó títulos infectivos en el mismo orden logarítmico que el ensayo de placas