Detection and Molecular Characterization of Enteric Viruses in Bivalve Mollusks Collected in Arraial do Cabo, Rio de Janeiro, Brazil

Metaviromic reveals the dynamics and diversity of the virosphere in wastewater samples from Natal, Brazil

The COVID-19 pandemic underscored the significance of omics technology and Wastewater-Based Epidemiology for epidemic preparedness. This study investigates the virosphere in wastewater samples from Natal (Brazil), aiming to understand its structure, relationships, and potential. Metaviromic analysis was used on DNA and RNA from weekly samples collected over a year (June/2021 to May/2022) from three wastewater treatment plants. The virosphere showed stability, particularly in viruses infecting microorganisms and plants. However, an alternation of representatives of viruses that infect animals has been observed. Among the most abundant viruses infecting microorganisms are genera associated with the bacterial genera Escherichia, Pseudomonas, and Caulobacte. Regarding the viruses infecting plants, Sobemovirus and Tobamovirus are the most abundant genera. Odontoglossum ringspot virus was identified as a possible RNA virus biomarker. Among DNA viruses infecting animals, genera Bocaparvovirus and Mastadenovirus are the most prevalent. Intriguingly, some Poxviridae family members were observed in the samples. Co-occurrence network analysis identified potential biomarkers like Volepox virus, Anatid herpesvirus 1, and Caviid herpesvirus 2. Among RNA viruses affecting animals, Mamastrovirus, Rotavirus, and Norovirus genera were the most abundant pathogens. Furthermore, members of the Coronaviridae family exhibited a high degree of centrality values in the co-occurrence network, even connecting with unclassified viruses. The study emphasizes the importance of research in understanding the roles of unclassified viruses. In addition, we observed an association between Coronaviridae reads, rainfall, and the number of reported COVID-19 cases. Our study highlights the diversity and complexity of the viral community in wastewater and the need for research to understand better the ecological roles unclassified viruses play. Such advances will significantly contribute to our preparedness and response to future viral threats. Furthermore, our study contributes to knowledge of virosphere dynamics, offering insights that can contribute to the direction of future public health policies and interventions.

Human norovirus in Brazil: an update of reports in different settings

Norovirus is an important etiologic agent of acute gastroenteritis and has become even more relevant in Brazil after the implementation of the monovalent rotavirus vaccine in 2006 through the public health system, now representing a significant portion of the etiology of acute diarrheal diseases. Although diagnosing acute gastroenteritis caused by norovirus is a relatively simple process, and the infection tends to be self-limited, the virus can be considerably harmful to vulnerable populations, such as children, the elderly, and immunocompromised individuals. The spread of norovirus is also particularly favorable among such groups due to its mode of transmission, favored by cluttered environments such as in hospitals and densely populated regions. Additionally, norovirus' ability to spread through water and food creates the need for measures to ensure adequate sanitation and the development of effective measures to prevent outbreaks and severe manifestations of the disease. This review aims to address the main reports of human norovirus detected in Brazil over the years, focusing on clinical-hospital, food-related, and urban conglomerate contexts, including the circulating strains.

Hepatitis A in Latin America: The current scenario

This review aims to gather and disseminate updated information regarding hepatitis A virus (HAV) in Latin America (LA) in the last 11 years, including seroprevalence, post-vaccination studies, virus detection in aqueous matrices and food samples, and outbreak reports. Only 24 seroprevalence studies were published between 2012 and 2023 with 55%-100% reported prevalences of anti-HAV IgG. Among the 25 LA countries, only eight of them have introduced HAV vaccines into their immunisation programs. Outbreaks of hepatitis A occurred between 2017-2019, mainly affecting men who have sex with men in Argentina, Brazil and Chile, probably as a consequence of the abrupt decline of young adults' immunity. This could be due to that young adult have never been infected in childhood (due to socio-health improvements) and are above the cut-off ages to be included when the vaccination programs were introduced. Although scarce, studies focused on environmental and food HAV surveillance have shown viral presence in these samples. Surface waters presented HAV detections between 1.2% and 86.7%, and untreated wastewaters between 2.8% and 70.9%. Genotypes found in all cases were IA and IC. The only wastewater-based epidemiology study showed to be a useful tool as a complement of traditional epidemiological surveillance. Only four LA countries have looked for HAV in food samples, with genome detection rates between 9% and 33%. Latin American HAV circulation scenario is changing. In countries where socioeconomic and sanitary conditions have not improved, the virus persists with high endemicity and the access to the vaccine should be re-evaluated by local governments. In countries where access to clean water, better sanitary conditions and HAV immunisation programs have been implemented, the number of cases among young adults seems to be increasing, alerting health authorities.

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.

Monitoring and Genotyping of Norovirus in Bivalve Molluscan Shellfish from Northern Italian Seas (2018-2020)

Norovirus (NoV) is an enteric virus with foodborne transmission. Bivalve shellfish are a main source of infections and outbreaks. In Italy a voluntary based monitoring plan to check the safety of bivalve shellfish was set up at provincial level. This study describes the occurrence and distribution of NoV in the Northern Adriatic Sea and in the Ligurian Sea. From October 2018 to September 2020, 807 bivalve shellfish samples (n = 205 oysters, n = 182 mussels, n = 348 clams, n = 72 other bivalve shellfish) were tested by One-Step Retrotranscription Real-time polymerase chain reaction for NoV GI and GII and quantified according to the ISO 15216-2:2013 and ISO 15216-1:2017. Positive samples were further analyzed to determine genotype by sequencing of the ORF1/ORF2 junction of the viral genome. A total of 126 samples were positive for NoV, mussels, and oysters had the highest probability of being positive and positive samples were found mainly in the colder season. Of these samples, 46% were NoV GII, 13% NoV GI, and 40% carried both genogroups. Thirty-seven samples were typeable (GI n = 12 and GII n = 25) with GI samples belonging to four genotypes and GII samples belonging to five genotypes. GII.3 genotype was the most prevalent, followed by GII.4, particularly Sydney 2012 subtype, a leading cause of infections worldwide, was found in three oysters' and three clams' samples. The phylogenetic analysis revealed a high heterogeneity among the species that are scattered in several clusters. Considering the low infectious dose the overall presence of NoV in edible shellfish, particular those to be eaten raw or undercooked, is moderately high. The presence of genotypes frequently involved in human infections strengthens the need for ongoing monitoring, which should be extended at national level.

Norovirus Epidemiology and Genotype Circulation during the COVID-19 Pandemic in Brazil, 2019-2022

Norovirus stands out as a leading cause of acute gastroenteritis (AGE) worldwide, affecting all age groups. In the present study, we investigated fecal samples from medically attended AGE patients received from nine Brazilian states, from 2019 to 2022, including the COVID-19 pandemic period. Norovirus GI and GII were detected and quantified using RT-qPCR, and norovirus-positive samples underwent genotyping through sequencing the ORF1/2 junction region. During the four-year period, norovirus prevalence was 37.2%, varying from 20.1% in 2020 to 55.4% in 2021. GII genotypes dominated, being detected in 92.9% of samples. GII-infected patients had significantly higher viral concentrations compared to GI-infected patients (median of 3.8 × 107 GC/g and 6.7 × 105 GC/g, respectively); and patients aged >12-24 months showed a higher median viral load (8 × 107 GC/g) compared to other age groups. Norovirus sequencing revealed 20 genotypes by phylogenetic analysis of RdRp and VP1 partial regions. GII.4 Sydney[P16] was the dominant genotype (57.3%), especially in 2019 and 2021, followed by GII.2[P16] (14.8%) and GII.6[P7] (6.3%). The intergenogroup recombinant genotype, GIX.1[GII.P15], was detected in five samples. Our study is the first to explore norovirus epidemiology and genotype distribution in Brazil during COVID-19, and contributes to understanding the epidemiological dynamics of norovirus and highlighting the importance of continuing to follow norovirus surveillance programs in Brazil.

Quantitative Risk Assessment of Five Foodborne Viruses in Shellfish Based on Multiplex qPCR

Foodborne diseases are currently the most critical food safety issue in the world. There are not many hazard identification and exposure assessments for foodborne viruses (Norovirus GI, GII, Hepatitis A Virus, Rotavirus, Adenovirus) in shellfish. Multiplex qPCR for the simultaneous detection of five foodborne viruses was established and used to assess infection risk based on a 1-year pathogenesis study. The sensitivity, specificity and reproducibility of the multiplex qPCR method are consistent with that of conventional qPCR, which saves more time and effort. Overall, 37.86% of shellfish samples had one or more foodborne viruses. Risk assessment formulae and matrices were used to develop risk assessments for different age groups, different seasons and different shellfish. The annual probability of contracting a foodborne virus infection from shellfish is greater than 1.6 × 10-1 for all populations, and even for infants aged 0-4 years, it is greater than 1.5 × 10-2, which is much higher than the risk thresholds recommended by WHO (10-6) and the US EPA (10-4). High risk (level IV) is associated with springtime, and medium risk (level III) is associated with Mussel consumption. This study provides a basis for the risk of foodborne viral infections in people of different ages, in different seasons, and by consuming different shellfish.

A Comprehensive Review for the Surveillance of Human Pathogenic Microorganisms in Shellfish

Bivalve molluscan shellfish have been consumed for centuries. Being filter feeders, they may bioaccumulate some microorganisms present in coastal water, either naturally or through the discharge of human or animal sewage. Despite regulations set up to avoid microbiological contamination in shellfish, human outbreaks still occur. After providing an overview showing their implication in disease, this review aims to highlight the diversity of the bacteria or enteric viruses detected in shellfish species, including emerging pathogens. After a critical discussion of the available methods and their limitations, we address the interest of technological developments using genomics to anticipate the emergence of pathogens. In the coming years, further research needs to be performed and methods need to be developed in order to design the future of surveillance and to help risk assessment studies, with the ultimate objective of protecting consumers and enhancing the microbial safety of bivalve molluscan shellfish as a healthy food.