Environmental Assessment of Classical Human Astrovirus in Uruguay

Bioinformatics-based screening tool identifies a wide variety of human and zoonotic viruses in Trujillo-Peru wastewater

Peru was one of the most affected countries during the COVID-19 pandemic. Moreover, multiple other viral diseases (enteric, respiratory, bloodborne, and vector-borne) are endemic and rising. According to Peru's Ministry of Health, various health facilities in the country were reallocated for the COVID-19 pandemic, thereby leading to reduced action to curb other diseases. Many viral diseases in the area are under-reported and not recognized. The One Health approach, in addition to clinical testing, incorporates environmental surveillance for detection of infectious disease outbreaks. The purpose of this work is to use a screening tool that is based on molecular methods, high throughput sequencing and bioinformatics analysis of wastewater samples to identify virus-related diseases circulating in Trujillo-Peru. To demonstrate the effectiveness of the tool, we collected nine untreated wastewater samples from the Covicorti wastewater utility in Trujillo-Peru on October 22, 2022. High throughput metagenomic sequencing followed by bioinformatic analysis was used to assess the viral diversity of the samples. Our results revealed the presence of sequences associated with multiple human and zoonotic viruses including Orthopoxvirus, Hepatovirus, Rhadinovirus, Parechovirus, Mamastrovirus, Enterovirus, Varicellovirus, Norovirus, Kobuvirus, Bocaparvovirus, Simplexvirus, Spumavirus, Orthohepevirus, Cardiovirus, Molliscipoxvirus, Salivirus, Parapoxvirus, Gammaretrovirus, Alphavirus, Lymphocryptovirus, Erythroparvovirus, Sapovirus, Cosavirus, Deltaretrovirus, Roseolovirus, Flavivirus, Betacoronavirus, Rubivirus, Lentivirus, Betapolyomavirus, Rotavirus, Hepacivirus, Alphacoronavirus, Mastadenovirus, Cytomegalovirus and Alphapapillomavirus. For confirmation purposes, we tested the samples for the presence of selective viruses belonging to the genera detected above. PCR based molecular methods confirmed the presence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), monkeypox virus (MPXV), noroviruses GI and GII (NoVGI and NoVGII), and rotavirus A (RoA) in our samples. Furthermore, publicly available clinical data for selected viruses confirm our findings. Wastewater or other environmental media surveillance, combined with bioinformatics methods, has the potential to serve as a systematic screening tool for the identification of human or zoonotic viruses that may cause disease. The results of this method can guide further clinical surveillance efforts and allocation of resources. Incorporation of this bioinformatic-based screening tool by public health officials in Peru and other Latin American countries will help manage endemic and emerging diseases that could save human lives and resources.

Activated sludge and UV-C254 for Sapovirus, Aichivirus, Astrovirus, and Adenovirus processing

In this study, the detection rates of four enteric viruses, Human Astrovirus (HAstVs), Aichivirus (AiVs), Human Adenovirus (HAdVs), and Sapovirus (SaVs) are carried out to assess the virological quality of the treated wastewater. A total of 140 samples was collected from wastewater treatment plant WWTP of Tunis-City. Real-time RT-PCR and conventional RT-PCR results showed high frequencies of detection of the four enteric viruses investigated at the entry and exit of the biological activated sludge procedure and a significant reduction in viral titers after tertiary treatment with UV-C254 irradiation. These results revealed the ineffectiveness of the biological activated sludge treatment in removing viruses and the poor quality of the treated wastewater intended for recycling, agricultural reuse, and safe discharge into the natural environment. The UV-C254 irradiation, selected while considering the non-release of known disinfection by-products because of eventual reactions with the large organic and mineral load commonly present in the wastewater.

Molecular Characterization of Gastroenteric Viruses in Wastewater from Cities in Uruguay

Group A Rotavirus, Human Astrovirus, and Norovirus (RVA, HAstV, and NoV) are recognized as the major causative agents of acute gastroenteritis in children and adults worldwide. The aim of this study was to determine the prevalence and molecular epidemiology of RVA, HAstV, and NoV in wastewater from three cities in Uruguay. Thirty-six samples from Bella Unión, Salto, and Fray Bentos cities were analyzed using quantitative and qualitative PCR. RVA was the most frequently detected virus (50%), followed by HAstV (39%), NoV GII (36%), and NoV GI (25%). RVA strains were characterized as P[8] and G3 based on the VP4 and VP7 genes, respectively. Among NoV-positive samples, genotypes GI.2, GI.3, GI.5, GI.6, GI.7, GII.2, GII.6, and GII.4 were detected, and only one HAstV genotype (MLB1) was found. Our wastewater-based epidemiological approach provides a snapshot of the overall genetic diversity of these viruses in three cities of the Uruguay River basin during 2017-2018. These findings reinforce the importance of this environmental surveillance tool for monitoring epidemiological trends of enteric viruses circulating in the population, which can be used to guide public health intervention.

Molecular epidemiology of classic, MLB and VA astroviruses isolated from <5 year-old children with gastroenteritis in Thailand, 2011-2016

This study aimed to investigate the molecular epidemiology and genetic diversity of astrovirus circulating in pediatric patients with acute gastroenteritis in Thailand. A total of 2034 fecal specimens collected between 2011 and 2016 from children hospitalized with acute gastroenteritis were analyzed for astrovirus infection using RT-PCR and nucleotide sequencing techniques. Overall, 54 samples were positive for astrovirus (2.6%). About half of the virus-positive samples (57.4%) were co-infection cases, mainly with rotavirus or norovirus. Genotyping revealed that three major clades, classic human astrovirus (HAstV) and newly emerging MLB and VA astroviruses co-circulated in the study population. At least seven different genotypes were identified and HAstV1 was the most predominant genotype detected (50%), followed by MLB1 (16.7%), HAstV4 (11.1%), HAstV5 and HAstV8 (7.4% each), MLB2 and VA2 (3.7% each). This study provided a useful information and contributed to molecular epidemiology of astroviruses including the novel MLB and VA astoviruses have been characterized and reported for the first time in Thailand.

Human Bocavirus: Detection, Quantification and Molecular Characterization in Sewage and Surface Waters in Uruguay

Human bocavirus (HBoV) infections are related to respiratory and gastroenteric diseases. The aim of this study was to investigate the presence of HBoV in both sewage and surface waters in Uruguay. Sixty-eight sewage samples from the cities of Salto, Paysandú, Bella Unión, Fray Bentos, Treinta y Tres and Melo and 36 surface water samples from the cities of Salto, Florida and Santa Lucía were studied. HBoV was screened by multiplex qPCR for the detection of the four subtypes, followed by monoplex qPCRs for the independent quantification of each subtype. A qualitative PCR followed by DNA sequencing and phylogenetic analysis was carried out for molecular characterization of HBoV strains. HBoV was present in a high frequency (69%) in sewage and only one positive sample (3%) was found in surface water. Concerning sewage samples, HBoV1 was detected in 11 (23%) out of the 47 positives samples, with a mean concentration of 8.2 × 10⁴ genomic copies/Liter (gc/L), HBoV3 was detected in 35 (74%) of the positive samples with a mean concentration of 4.1 × 10⁶ gc/L and subtypes 2 and/or 4 were detected in 39 (83%) of the positive samples with a mean concentration of 7.8 × 10⁶ gc/L. After the phylogenetic analysis performed by a Bayesian approach, the four HBoV subtypes were confirmed. This is the first study determining a high frequency of HBoV and the presence of the four HBoV subtypes in aquatic matrices in Latin America, mainly in sewage. Although HBoV was scarcely detected in surface water, a waterborne transmission is likely to occur if people enter in contact with polluted surface waters for recreational activities such as fishing or swimming since an elevated frequency of HBoV was detected in raw sewage which is usually directly discharged into surface waters.

Epidemiology and genetic diversity of classic human astrovirus among hospitalized children with acute gastroenteritis in Uruguay

Classic Human Astrovirus (Classic HAstV) are one of the most important causes of pediatric acute gastroenteritis (AGE), after rotaviruses and arguably caliciviruses. The aim of this study was to determine the molecular epidemiology of Classic HAstV from 175 clinical samples, being 153 stools and 22 vomits, collected from pediatric hospitalized patients with AGE in Salto city, Uruguay, from January 2011 to December 2012. Classic HAstV were detected and genotyped by using a qualitative Retro Transcription-Polimerase Chain Reaction (RT-PCR) directed to the Open Reading Frame-2 (ORF2) region C. Amplicons were sequenced and phylogenetic analyses were carried out in order to determine genotypes and lineages. Classic HAstV were detected in 18 out of 175 analyzed samples (10.3%) and 14 of them (78.0%) were successfully sequenced being 6 (42.8%) classified as HAstV-1 (1a lineage), 4 (28.6%) as HAstV-2 (2c lineage), and 4 (28.6%) as HAstV-3 (3c lineage). A higher detection of Classic HAstV infections was observed in autumn for both years of surveillance, and the majority of the positive cases were observed in 2011. The group of children between 2 and 5 years old presented the higher percentage of infections. To our knowledge, the present study represents the first report of astrovirus from acute gastroenteritis cases in Uruguay, evidencing its role as a relevant etiologic agent in severe cases of this disease.

Deciphering the Diversities of Astroviruses and Noroviruses in Wastewater Treatment Plant Effluents by a High-Throughput Sequencing Method

Although clinical epidemiology lists human enteric viruses to be among the primary causes of acute gastroenteritis in the human population, their circulation in the environment remains poorly investigated. These viruses are excreted by the human population into sewers and may be released into rivers through the effluents of wastewater treatment plants (WWTPs). In order to evaluate the viral diversity and loads in WWTP effluents of the Paris, France, urban area, which includes about 9 million inhabitants (approximately 15% of the French population), the seasonal occurrence of astroviruses and noroviruses in 100 WWTP effluent samples was investigated over 1 year. The coupling of these measurements with a high-throughput sequencing approach allowed the specific estimation of the diversity of human astroviruses (human astrovirus genotype 1 [HAstV-1], HAstV-2, HAstV-5, and HAstV-6), 7 genotypes of noroviruses (NoVs) of genogroup I (NoV GI.1 to NoV GI.6 and NoV GI.8), and 16 genotypes of NoVs of genogroup II (NoV GII.1 to NoV GII.7, NoV GII.9, NoV GII.12 to NoV GII.17, NoV GII.20, and NoV GII.21) in effluent samples. Comparison of the viral diversity in WWTP effluents to the viral diversity found by analysis of clinical data obtained throughout France underlined the consistency between the identified genotypes. However, some genotypes were locally present in effluents and were not found in the analysis of the clinical data. These findings could highlight an underestimation of the diversity of enteric viruses circulating in the human population. Consequently, analysis of WWTP effluents could allow the exploration of viral diversity not only in environmental waters but also in a human population linked to a sewerage network in order to better comprehend viral epidemiology and to forecast seasonal outbreaks.