•Though potential zoonotic swine enteric viruses are common and thought to be evolving, the level and type of health risk they pose to the public have been understated.•The transmission risk of ...potential zoonotic enteric viruses from swine to humans is higher in individuals with occupational work related to swine.•The intensification and globalization of pig production increase the interactions of human-swine/pig products and the risk of zoonotic pathogens.
Swine could serve as a natural reservoir for a large variety of viruses, including potential zoonotic enteric viruses. The presence of viruses with high genetic similarity between porcine and human strains may result in the emergence of zoonotic or xenozoonotic infections. Furthermore, the globalization and intensification of swine industries exacerbate the transmission and evolution of zoonotic viruses among swine herds and individuals working in swine-related occupations. To effectively prevent the public health risks posed by zoonotic swine enteric viruses, designing, and implementing a comprehensive measure for early diagnosis, prevention, and mitigation, requires interdisciplinary a collaborative ‘‘One Health" approach from veterinarians, environmental and public health professionals, and the swine industry. In this paper, we reviewed the current knowledge of selected potential zoonotic swine enteric viruses and explored swine intensive production and its associated public health risks.
GII.4 noroviruses are a major cause of acute gastroenteritis. Their dominance has been partially explained by the continuous emergence of antigenically distinct variants. To gain insights into the ...mechanisms of viral emergence and population dynamics of GII.4 noroviruses, we performed large-scale genomics, structural, and mutational analyses of the viral capsid protein (VP1). GII.4 noroviruses exhibited a periodic replacement of predominant variants with accumulation of amino acid substitutions. Genomic analyses revealed (i) a large proportion (87%) of conserved residues; (ii) variable residues that map on the previously determined antigenic sites; and (iii) variable residues that map outside the antigenic sites. Residues in the third pattern category formed motifs on the surface of VP1, which suggested extensions of previously predicted and new uncharacterized antigenic sites. The role of two motifs (C and G) in the antigenic makeup of the GII.4 capsid protein was confirmed with monoclonal antibodies and carbohydrate blocking assays. Amino acid profiles from antigenic sites (A, C, D, E, and G) correlated with the circulation patterns of GII.4 variants, with three of them (A, C, and G) containing residues (352, 357, 368, and 378) linked with the diversifying selective pressure on the emergence of new GII.4 variants. Notably, the emergence of each variant was followed by stochastic diversification with minimal changes that did not progress toward the next variant. This report provides a methodological framework for antigenic characterization of viruses and expands our understanding of the dynamics of GII.4 noroviruses and could facilitate the design of cross-reactive vaccines.
Noroviruses are an important cause of viral gastroenteritis around the world. An obstacle delaying the development of norovirus vaccines is inadequate understanding of the role of norovirus diversity in immunity. Using a population genomics approach, we identified new residues on the viral capsid protein (VP1) from GII.4 noroviruses, the predominant genotype, that appear to be involved in the emergence and antigenic topology of GII.4 variants. Careful monitoring of the substitutions in those residues involved in the diversification and emergence of new viruses could help in the early detection of future novel variants with pandemic potential. Therefore, this novel information on the antigenic diversification could facilitate GII.4 norovirus vaccine design.
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.
Noroviruses are a very diverse group of viruses that infect different mammalian species. In humans, norovirus is a major cause of acute gastroenteritis. Multiple norovirus infections can occur in a ...lifetime as the result of limited duration of acquired immunity and cross-protection among different strains. A combination of advances in sequencing methods and improvements on surveillance has provided new insights into norovirus diversification and emergence. The generation of diverse norovirus strains has been associated with (1) point mutations on two different genes: ORF1, encoding the non-structural proteins, and ORF2, encoding the major capsid protein (VP1); and (2) recombination events that create chimeric viruses. While both mechanisms are exploited by all norovirus strains, individual genotypes utilize each mechanism differently to emerge and persist in the human population. GII.4 noroviruses (the most prevalent genotype in humans) present an accumulation of amino acid mutations on VP1 resulting in the chronological emergence of new variants. In contrast, non-GII.4 noroviruses present co-circulation of different variants over long periods with limited changes on their VP1. Notably, genetic diversity of non-GII.4 noroviruses is mostly related to the high number of recombinant strains detected in humans. While it is difficult to determine the precise mechanism of emergence of epidemic noroviruses, observations point to multiple factors that include host-virus interactions and changes on two regions of the genome (ORF1 and ORF2). Larger datasets of viral genomes are needed to facilitate comparison of epidemic strains and those circulating at low levels in the population. This will provide a better understanding of the mechanism of norovirus emergence and persistence.
Vesivirus 2117 is an adventitious agent that has been responsible for lost productivity in biopharmaceutical production following contamination of Chinese hamster ovary cell cultures in commercial ...bioreactors. A member of the
, 2117 is classified within the Vesivirus genus in a clade that includes canine and mink caliciviruses but is distinct from the vesicular exanthema of swine virus (VESV) clade, which includes the extensively studied feline calicivirus (FCV). We have used cryogenic electron microscopy (cryo-EM) to determine the structure of the capsid of this small, icosahedral, positive-sense-RNA-containing virus. We show that the outer face of the dimeric capsomeres, which contains the receptor binding site and major immunodominant epitopes in all caliciviruses studied thus far, is quite different from that of FCV. This is a consequence of a 22-amino-acid insertion in the sequence of the FCV major capsid protein that forms a "cantilevered arm" that both plays an important role in receptor engagement and undergoes structural rearrangements thought to be important for genome delivery to the cytosol. Our data highlight a potentially important difference in the attachment and entry pathways employed by the different clades of the
genus.
Vesivirus 2117 has caused significant losses in manufacturing of biopharmaceutical products following contamination of cell cultures used in their production. We report the structure of the vesivirus 2117 capsid, the shell that encloses the virus's genome. Comparison of this structure with that of a related vesivirus, feline calicivirus (FCV), highlighted potentially important differences related to virus attachment and entry. Our findings suggest that these two viruses may bind differently to receptors at the host cell surface. We also show that a region of the capsid protein of FCV that rearranges following receptor engagement is not present in vesivirus 2117. These structural changes in the FCV capsid have been shown to allow the assembly of a portal-like structure that is hypothesized to deliver the viral genome to the cell's interior. Our data suggest that the 2117 portal assembly may employ a different means of anchoring to the outer face of the capsid.
A highly divergent bovine calicivirus was identified in an Indian calf with enteritis. The whole genome of this virus was sequenced, revealing distinct amino acid motifs in the polyprotein encoded by ...open reading frame 1 (ORF1) that are unique to caliciviruses. Phylogenetic analysis showed that it was related to members of the genus
Nebovirus
of the family
Caliciviridae.
Although it showed only 33.7–34.2% sequence identity in the VP1 protein to the nebovirus prototype strains, it showed 90.6% identity in VP1 to Kirklareli virus, a nebovirus detected in calves with enteritis in Turkey in 2012. An in-house-designed and optimized reverse transcription polymerase chain reaction (RT-PCR) assay was used to screen 120 archived bovine diarrhoeic fecal samples, 40 each from the Indian states of Uttar Pradesh, Haryana, and Himachal Pradesh, revealing frequent circulation of these divergent caliciviruses in the bovine population, with an overall positivity rate of 64.17% (77/120). This underscores the importance of conducting a comprehensive investigation of the prevalence of these divergent caliciviruses and assessing their associations with other pathogens responsible for enteritis in India.
Accurate knowledge of incubation period is important to investigate and to control infectious diseases and their transmission, however statements of incubation period in the literature are often ...uncited, inconsistent, and/or not evidence based.
In a systematic review of the literature on five enteric viruses of public health importance, we found 256 articles with incubation period estimates, including 33 with data for pooled analysis.
We fit a log-normal distribution to pooled data and found the median incubation period to be 4.5 days (95% CI 3.9-5.2 days) for astrovirus, 1.2 days (95% CI 1.1-1.2 days) for norovirus genogroups I and II, 1.7 days (95% CI 1.5-1.8 days) for sapovirus, and 2.0 days (95% CI 1.4-2.4 days) for rotavirus.
Our estimates combine published data and provide sufficient quantitative detail to allow for these estimates to be used in a wide range of clinical and modeling applications. This can translate into improved prevention and control efforts in settings with transmission or the risk of transmission.
The purpose of this study was to examine global epidemiological trends in human norovirus (NoV) outbreaks by transmission route and setting, and describe relationships between these characteristics, ...viral attack rates, and the occurrence of genogroup I (GI) or genogroup II (GII) strains in outbreaks. We analysed data from 902 reverse transcriptase–polymerase chain reaction-confirmed, human NoV outbreaks abstracted from a systematic review of articles published from 1993 to 2011 and indexed under the terms ‘norovirus’ and ‘outbreak’. Multivariate regression analyses demonstrated that foodservice and winter outbreaks were significantly associated with higher attack rates. Foodborne and waterborne outbreaks were associated with multiple strains (GI+GII). Waterborne outbreaks were significantly associated with GI strains, while healthcare-related and winter outbreaks were associated with GII strains. These results identify important trends for epidemic NoV detection, prevention, and control.
Noroviruses are increasingly recognized as a major cause of sporadic and epidemic acute gastroenteritis (AGE). Although there have been multiple studies published on norovirus epidemiology in Latin ...America, no comprehensive assessment of the role of norovirus has been conducted in the region. We aim to estimate the role of norovirus in the Latin American region through a systematic review and meta-analysis of the existing literature.
We carried out a literature search in MEDLINE, SciELO and LILACS. We included papers that provided information on the prevalence or incidence of norovirus (including seroprevalence studies and outbreaks), with a recruitment and/or follow-up period of at least 12 months and where the diagnosis of norovirus was confirmed by reverse transcription polymerase chain reaction. The data were pooled for meta-analysis to estimate the prevalence of norovirus AGE and norovirus asymptomatic infection with 95% confidence intervals (CIs).
Thirty-eight studies were included in the review. Overall, the prevalence of norovirus among AGE cases was 15% (95% CI: 13-18). By location, it was 15% in the community (95% CI: 11%-21%), 14% in outpatient settings (95% CI: 10%-19%) and 16% in hospital locations (95% CI: 12%-21%). The prevalence of norovirus among asymptomatic subjects was 8% (95% CI: 4-13). Norovirus GII.4 strains were associated with 37%-100% of norovirus AGE cases, but only 7% of norovirus asymptomatic detections.
Noroviruses are associated with almost 1 out of every 6 hospitalizations because of acute diarrhea in children younger than 5 years of age in Latin America.
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