The molecular epidemiology of hepatitis E virus genotype 3 in Canada.

Autochthonous hepatitis E virus (HEV) infection is increasingly reported in industrialized countries and is mostly associated with zoonotic HEV genotype 3 (HEV-3). In this study, we examined the molecular epidemiology of 63 human clinical HEV-3 isolates in Canada between 2014 and 2022. Fifty-five samples were IgM positive, 45 samples were IgG positive and 44 were IgM and IgG positive. The majority of the isolates belong to the subtypes 3a, 3b, and 3j, with high sequence homology to Canadian swine and pork isolates. There were a few isolates that clustered with subtypes 3c, 3e, 3f, 3h, and 3g, and an isolate from chronic infection with a rabbit strain (3ra). Previous studies have demonstrated that the isolates from pork products and swine from Canada belong to subtypes 3a and 3b, therefore, domestic swine HEV is likely responsible for the majority of clinical HEV cases in Canada and further support the hypothesis that swine serve as the main reservoirs for HEV-3 infections. Understanding the associated risk of zoonotic HEV infection requires the establishment of sustainable surveillance strategies at the interface between humans, animals, and the environment within a One-Health framework.

Optimization of the replication of hepatitis E virus genotype 3 in vitro.

AIMS: Hepatitis E virus (HEV) is responsible for ∼20 million human infections worldwide every year. The genotypes HEV-3 and HEV-4 are zoonotic and are responsible for most of the autochthonous HEV cases in high-income countries. There are several cell culture systems that allow for propagation of different HEV genotypes in vitro. One of these systems uses human lung carcinoma cells (A549), and was further optimized for propagation of HEV-3 47832c strain. In this study, we investigated the effect of different media supplements as well as microRNA-122 (miR-122) on improving the replication of HEV-3 47832c in A549 cells. METHODS AND RESULTS: We observed that supplementation of maintenance media with 5% fetal bovine serum was sufficient for efficient replication of HEV-3, and verified the positive effect of media supplementation with Amphotericin B, MgCl2, and dimethyl sulfoxide on replication of HEV-3. We have also demonstrated that adding miR-122 mimics to the culture media does not have any significant effect on the replication of HEV-3 47832c. CONCLUSIONS: Herein, we detected over a 6-fold increase in HEV-3 replication in A549/D3 cells by adding all three supplements: Amphotericin B, MgCl2, and dimethyl sulfoxide to the culture media, while demonstrating that miR-122 might not play a key role in replication of HEV-3 47832c.

Examining the efficiency of porcine gastric mucin-coated magnetic beads in extraction of noroviruses from frozen berries.

Human norovirus is the leading cause of foodborne gastroenteritis worldwide. Due to the low infectious dose of noroviruses, sensitive methodologies are required to detect and characterize small numbers of viral particles that are found in contaminated foods. The ISO 15216 method, which is internationally recognized for detection of foodborne viruses from high-risk food commodities, is based on viral precipitation, followed by RNA extraction and identification of the viral genome by RT-PCR. Although the ISO 15216 method is efficient, it is time consuming and tedious, does not report on the viral infectivity, and is sensitive to the presence of RT-PCR inhibitors. Norovirus capture by the porcine gastric mucin conjugated magnetic beads (PGM-MB) was developed as an alternative virus recovery method. It relies on the integrity of the viral capsid being able to bind to PGM. PGM contains a variety of histo-blood group antigens (HBGAs) that act as norovirus receptors. Therefore, the PGM-MB method allows for extraction of noroviruses, with potentially intact viral capsids, from complex food matrices. The viral genome can then be released through heat-shock of the captured virus. For this reason, we performed a parallel comparison between the ISO 15216 method and the PGM-MB method in isolation and quantification of noroviruses from frozen raspberries. We have demonstrated that the efficiency of the PGM-MB method in extraction of murine norovirus (MNV) and human norovirus GII.4 from raspberries is equal or better than the ISO 15216 method, while the PGM-MB has fewer steps and shorter turnaround time. Moreover, the PGM-MB method is more efficient in removing the inhibitors prior to RT-PCR analysis.

Rat Hepatitis E Virus in Norway Rats, Ontario, Canada, 2018-2021.

We tested liver samples from 372 Norway rats (Rattus norvegicus) from southern Ontario, Canada, during 2018-2021 to investigate presence of hepatitis E virus infection. Overall, 21 (5.6%) rats tested positive for the virus. Sequence analysis demonstrated all infections to be rat hepatitis E virus (Rocahepevirus ratti genotype C1).

Efficacy of washing produce in removing human coronavirus OC43 and murine norovirus.

AIMS: Fresh produce is often a vehicle for the transmission of foodborne pathogens such as human norovirus. Thus, it is recommended to wash the surface of produce before consumption, and one of the most common ways to wash produce is by rinsing under running tap water. This study determined the effectiveness of removal of human coronavirus-OC43 (HCoV-OC43), as a surrogate for severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) and murine norovirus-1 (MNV-1), as a surrogate for human norovirus, from contaminated lettuce, apples and cucumbers. METHODS AND RESULTS: The produce surfaces were artificially inoculated in conjunction with faecal material to represent natural contamination. Rinsing under tap water for 10 s at 40 ml/s removed 1.94 ± 0.44, 1.42 ± 0.00 and 1.42 ± 0.42 log of HCoV-OC43 from apple, cucumber and lettuce respectively. The same washing technique removed 1.77 ± 0.17, 1.42 ± 0.07 and 1.79 ± 0.14 log of MNV-1 from apple, cucumber and lettuce respectively. This washing technique was effective at reducing a significant amount of viral contamination, however, it was not enough to eliminate the entire contamination. There was no significant difference in the reduction of viral load between the two viruses, nor between the three surfaces tested in this study. CONCLUSIONS: Our data suggest that washing under tap water would be an efficient way of reducing the risk of foodborne viral transmission only if the level of contamination is less than 2 log PFU. SIGNIFICANCE AND IMPACT OF STUDY: This study demonstrates that running tap water was effective at reducing the amount of infectious HCoV-OC43 and MNV on produce surfaces, and washing produce continues to be an important task to perform prior to consumption to avoid infection by foodborne viruses, particularly for foods which are eaten raw.

Exploring the potential of foodborne transmission of respiratory viruses.

The ongoing pandemic involving severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has raised the question whether this virus, which is known to be spread primarily though respiratory droplets, could be spread through the fecal-oral route or via contaminated food. In this article, we present a critical review of the literature exploring the potential foodborne transmission of several respiratory viruses including human coronaviruses, avian influenza virus (AVI), parainfluenza viruses, human respiratory syncytial virus, adenoviruses, rhinoviruses, and Nipah virus. Multiple lines of evidence, including documented expression of receptor proteins on gastrointestinal epithelial cells, in vivo viral replication in gastrointestinal epithelial cell lines, extended fecal shedding of respiratory viruses, and the ability to remain infectious in food environments for extended periods of time raises the theoretical ability of some human respiratory viruses, particularly human coronaviruses and AVI, to spread via food. However, to date, neither epidemiological data nor case reports of clear foodborne transmission of either viruses exist. Thus, foodborne transmission of human respiratory viruses remains only a theoretical possibility.

Examining the persistence of human Coronavirus 229E on fresh produce.

Human coronaviruses (HCoVs) are mainly associated with respiratory infections. However, there is evidence that highly pathogenic HCoVs, including severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and Middle East Respiratory Syndrome (MERS-CoV), infect the gastrointestinal (GI) tract and are shed in the fecal matter of the infected individuals. These observations have raised questions regarding the possibility of fecal-oral route as well as foodborne transmission of SARS-CoV-2 and MERS-CoV. Studies regarding the survival of HCoVs on inanimate surfaces demonstrate that these viruses can remain infectious for hours to days, however, there is limited data regarding the viral survival on fresh produce, which is usually consumed raw or with minimal heat processing. To address this knowledge gap, we examined the persistence of HCoV-229E, as a surrogate for highly pathogenic HCoVs, on the surface of commonly consumed fresh produce, including: apples, tomatoes, cucumbers and lettuce. Herein, we demonstrated that viral infectivity declines within a few hours post-inoculation (p.i) on apples and tomatoes, and no infectious virus was detected at 24h p.i, while the virus persists in infectious form for 72h p.i on cucumbers and lettuce. The stability of viral RNA was examined by droplet-digital RT-PCR (ddRT-PCR), and it was observed that there is no considerable reduction in viral RNA within 72h p.i.

Foodborne viral outbreaks associated with frozen produce.

Over the past decade, frozen fruits have been a major vehicle of foodborne illnesses mainly attributed to norovirus (NoV) and hepatitis A virus (HAV) infections. Fresh produce may acquire viral contamination by direct contact with contaminated surface, water or hands, and is then frozen without undergoing proper decontamination. Due to their structural integrity, foodborne viruses are able to withstand hostile conditions such as desiccation and freezing, and endure for a long period of time without losing their infectivity. Additionally, these foods are often consumed raw or undercooked, which increases the risk of infection. Herein, we searched published literature and databases of reported outbreaks as well as the databases of news articles for the viral outbreaks associated with the consumption of frozen produce between January 2008 and December 2018; recorded the worldwide distribution of these outbreaks; and analysed the implication of consumption of different types of contaminated frozen food. In addition, we have briefly discussed the factors that contribute to an increased risk of foodborne viral infection following the consumption of frozen produce. Our results revealed that frozen fruits, especially berries and pomegranate arils, contributed to the majority of the outbreaks, and that most outbreaks were reported in industrialised countries.

Evaluation of porcine gastric mucin assay for detection and quantification of human norovirus in fresh herbs and leafy vegetables.

Leafy vegetables and fresh herbs are important parts of a healthy diet, however, they can be common vehicles of norovirus (NoV) infection and lead to serious health and economic concerns globally. NoV is highly infectious and persistent in the food and the environment, while being resistant to conventional food decontamination practices. Herbs and leafy greens are often consumed raw, and if contaminated with NoV, they may cause illness. Consequently, for outbreak prevention and surveillance purposes, sensitive and rapid methods are required to detect the presence of infectious NoV in naturally contaminated produce during its shelf life. Herein, we compared the extraction efficiency of the ISO/TS 15216-1:2017 method with the porcine gastric mucin coated magnetic beads (PGM-MB) assay, combined with heat-denaturation for RNA extraction, for detection of human NoV in artificially contaminated fresh green seaweed, basil, mint, and baby spinach. Droplet-digital RT-PCR was used to quantify the extracted genome by both methods. Our data demonstrated that while the PGM-MB assay takes considerably less time, it yields significantly higher recovery rates compared with the ISO/TS 15216-1:2017. Furthermore, since this method has the ability to be adapted in high-throughput and automated systems, it can be further modified to be employed by the food industry to reduce the number of NoV illnesses and outbreaks at the source of distribution.

Genetic characterization of norovirus GII.4 variants circulating in Canada using a metagenomic technique.

BACKGROUND: Human norovirus is the leading cause of viral gastroenteritis globally, and the GII.4 has been the most predominant genotype for decades. This genotype has numerous variants that have caused repeated epidemics worldwide. However, the molecular evolutionary signatures among the GII.4 variants have not been elucidated throughout the viral genome. METHOD: A metagenomic, next-generation sequencing method, based on Illumina RNA-Seq, was applied to determine norovirus sequences from clinical samples. RESULTS: Herein, the obtained deep-sequencing data was employed to analyze full-genomic sequences from GII.4 variants prevailing in Canada from 2012 to 2016. Phylogenetic analysis demonstrated that the majority of these sequences belong to New Orleans 2009 and Sydney 2012 strains, and a recombinant sequence was also identified. Genome-wide similarity analyses implied that while the capsid gene is highly diverse among the isolates, the viral protease and polymerase genes remain relatively conserved. Numerous amino acid substitutions were observed at each putative antigenic epitope of the VP1 protein, whereas few amino acid changes were identified in the polymerase protein. Co-infection with other enteric RNA viruses was investigated and the astrovirus genome was identified in one of the samples. CONCLUSIONS: Overall this study demonstrated the application of whole genome sequencing as an important tool in molecular characterization of noroviruses.

Navigating Microbiological Food Safety in the Era of Whole-Genome Sequencing.

The epidemiological investigation of a foodborne outbreak, including identification of related cases, source attribution, and development of intervention strategies, relies heavily on the ability to subtype the etiological agent at a high enough resolution to differentiate related from nonrelated cases. Historically, several different molecular subtyping methods have been used for this purpose; however, emerging techniques, such as single nucleotide polymorphism (SNP)-based techniques, that use whole-genome sequencing (WGS) offer a resolution that was previously not possible. With WGS, unlike traditional subtyping methods that lack complete information, data can be used to elucidate phylogenetic relationships and disease-causing lineages can be tracked and monitored over time. The subtyping resolution and evolutionary context provided by WGS data allow investigators to connect related illnesses that would be missed by traditional techniques. The added advantage of data generated by WGS is that these data can also be used for secondary analyses, such as virulence gene detection, antibiotic resistance gene profiling, synteny comparisons, mobile genetic element identification, and geographic attribution. In addition, several software packages are now available to generate in silico results for traditional molecular subtyping methods from the whole-genome sequence, allowing for efficient comparison with historical databases. Metagenomic approaches using next-generation sequencing have also been successful in the detection of nonculturable foodborne pathogens. This review addresses state-of-the-art techniques in microbial WGS and analysis and then discusses how this technology can be used to help support food safety investigations. Retrospective outbreak investigations using WGS are presented to provide organism-specific examples of the benefits, and challenges, associated with WGS in comparison to traditional molecular subtyping techniques.

Activity-based profiling of the proteasome pathway during hepatitis C virus infection.

Hepatitis C virus (HCV) infection often leads to chronic hepatitis, liver cirrhosis, and hepatocellular carcinoma. The stability of the HCV proteins is controlled by ubiquitin-dependent and ubiquitin-independent proteasome pathways. Many viruses modulate proteasome function for their propagation. To examine the interrelationship between HCV and the proteasome pathways we employed a quantitative activity-based protein profiling method. Using this approach we were able to quantify the changes in the activity of several proteasome subunits and found that proteasome activity is drastically reduced by HCV replication. The results imply a link between the direct downregulation of the activity of this pathway and chronic HCV infection.

Hepatitis C virus induced up-regulation of microRNA-27: a novel mechanism for hepatic steatosis.

UNLABELLED: MicroRNAs (miRNAs) are small RNAs that posttranscriptionally regulate gene expression. Their aberrant expression is commonly linked with diseased states, including hepatitis C virus (HCV) infection. Herein, we demonstrate that HCV replication induces the expression of miR-27 in cell culture and in vivo HCV infectious models. Overexpression of the HCV proteins core and NS4B independently activates miR-27 expression. Furthermore, we establish that miR-27 overexpression in hepatocytes results in larger and more abundant lipid droplets, as observed by coherent anti-Stokes Raman scattering (CARS) microscopy. This hepatic lipid droplet accumulation coincides with miR-27b's repression of peroxisome proliferator-activated receptor (PPAR)-α and angiopoietin-like protein 3 (ANGPTL3), known regulators of triglyceride homeostasis. We further demonstrate that treatment with a PPAR-α agonist, bezafibrate, is able to reverse the miR-27b-induced lipid accumulation in Huh7 cells. This miR-27b-mediated repression of PPAR-α signaling represents a novel mechanism of HCV-induced hepatic steatosis. This link was further demonstrated in vivo through the correlation between miR-27b expression levels and hepatic lipid accumulation in HCV-infected SCID-beige/Alb-uPa mice. CONCLUSION: Collectively, our results highlight HCV's up-regulation of miR-27 expression as a novel mechanism contributing to the development of hepatic steatosis.

A new chemical probe for phosphatidylinositol kinase activity.

Phosphatidylinositol kinases (PIKs) are key enzymatic regulators of membrane phospholipids and membrane environments that control many aspects of cellular function, from signal transduction to secretion, through the Golgi apparatus. Here, we have developed a photoreactive "clickable" probe, PIK-BPyne, to report the activity of PIKs. We investigated the selectivity and efficiency of the probe to both inhibit and label PIKs, and we compared PIK-BPyne to a wortmannin activity-based probe also known to target PIKs. We found that PIK-BPyne can act as an effective in situ activity-based probe, and for the first time, report changes in PI4K-IIIß activity induced by the hepatitis C virus. These results establish the utility of PIK-BPyne for activity-based protein profiling studies of PIK function in native biological systems.

Detection of Foodborne RNA Viruses by Reverse Transcriptase Droplet Digital PCR.

Foodborne viruses remain the largest cause of human gastroenteritis and one of the largest contributors to foodborne illnesses worldwide. Currently, quantitative reverse transcription PCR (qRT-PCR) or real-time qPCR are the detection methods commonly used for quantification of foodborne viruses, but those methods have several disadvantages, such as relying on standard curves for quantification and the background noise from a bulk reaction. ddPCR uses an oil-water emulsion to form multiple droplets that partition small amounts of viral genetic material (DNA or RNA) into each of the droplets. These droplets then undergo amplification cycles and are analyzed using Poisson distributions. This allows for absolute quantification without the need for a standard curve, which makes ddPCR a precise tool in surveillance of foodborne viruses. Herein, we describe the process of detecting foodborne viruses using RNA isolated from various matrices. Up to 96 samples including the positive and negative controls can be analyzed on a single plate by ddPCR.

Assessing the efficacy of different bead-based assays in capturing hepatitis E virus.

Hepatitis E virus (HEV) generally causes acute liver infection in humans and its transmission could be waterborne, foodborne, bloodborne, or zoonotic. To date, there is no standard method for the detection of HEV from food and environmental samples. Herein, we explored the possibility of using magnetic beads for the capture and detection of HEV. For this purpose, we employed Dynabeads M-270 Epoxy magnetic beads, coated with different monoclonal antibodies (mAbs) against HEV capsid protein, and the Nanotrap Microbiome A Particle magnetic beads, which are coated with chemical affinity baits, to capture HEV-3 particles in suspension. Viral RNA was extracted by heat-shock or QIAamp viral RNA kit and subjected to quantification using digital-droplet RT-PCR (ddRT-PCR). We demonstrated that the mAb-coupled Dynabeads and the Nanotrap particles, both were able to successfully capture HEV-3. The latter, however had lower limit of detection (<140gc compared with <1400 gc) and significantly higher extraction efficiency in comparison to the mAb-coupled Dynabeads (41.1% vs 8.8%). We have also observed that viral RNA extraction by heat-shock is less efficient compared to using highly denaturing reagents in QIAmp viral RNA extraction kit. As such, magnetic beads have the potential to be used to capture HEV virions for research and surveillance purposes.

Centrifugal microfluidic system for colorimetric sample-to-answer detection of viral pathogens.

We describe a microfluidic system for conducting thermal lysis, polymerase chain reaction (PCR) amplification, hybridization, and colorimetric detection of foodborne viral organisms in a sample-to-answer format. The on-chip protocol entails 24 steps which are conducted by a centrifugal platform that allows for actuating liquids pneumatically during rotation and so facilitates automation of the workflow. The microfluidic cartridge is fabricated from transparent thermoplastic polymers and accommodates assay components along with an embedded micropillar array for detection and read-out. A panel of oligonucleotide primers and probes has been developed to perform PCR and hybridization assays that allows for identification of five different viruses, including pathogens such as norovirus and hepatitis A virus (HAV) in a multiplexed format using digoxigenin-labelled amplicons and immunoenzymatic conversion of a chromogenic substrate. Using endpoint detection, we demonstrate that the system can accurately and repetitively (n = 3) discriminate positive and negative signals for HAV at 350 genome copies per µL. As part of the characterization and optimization process, we show that the implementation of multiple (e.g., seven) micropillar arrays in a narrow fluidic pathway can lead to variation (up to 50% or more) in the distribution of colorimetric signal deriving from the assay. Numerical modeling of flow behaviour was used to substantiate these findings. The technology-by virtue of automation-can provide a pathway toward rapid detection of viral pathogens, shortening response time in food safety surveillance, compliance, and enforcement as well as outbreak investigations.

Animal reservoirs for hepatitis E virus within the Paslahepevirus genus.

Hepatitis E virus (HEV) is responsible for acute hepatitis in humans. It is a single-stranded, positive-sense RNA virus that belongs to the Hepeviridae family. The majority of concerning HEV genotypes belong to the Paslahepevirus genus and are subsequently divided into eight genotypes. HEV genotypes 1 and 2 exclusively infect humans and primates while genotypes 3 and 4 infect both humans and other mammals. Whereas HEV genotypes 5 and 6 are isolated from wild boars and genotypes 7 and 8 were identified from camels in the United Arab Emirates and China, respectively. HEV mainly spreads from humans to humans via the fecal-oral route. However, some genotypes with the capability of zoonotic transmissions, such as 3 and 4 transmit from animals to humans through feces, direct contact, and ingestion of contaminated meat products. As we further continue to uncover novel HEV strains in various animal species, it is becoming clear that HEV has a broad host range. Therefore, understanding the potential animal reservoirs for this virus will allow for better risk management and risk mitigation of infection with HEV. In this review, we mainly focused on animal reservoirs for the members of the species Paslahepevirus balayani and provided a comprehensive list of the host animals identified to date.

Protective Effect of Food Against Inactivation of Human Coronavirus OC43 by Gastrointestinal Fluids.

The involvement of the gastrointestinal (GI) tract in severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection has been reported in multiple studies. Since it has been demonstrated that human intestinal epithelial cells support productive viral replication and that a substantial portion of infected individuals shed the virus in feces, the possibility of fecal-oral and fecal-respiratory modes of transmission have been proposed for SARS-CoV-2. In order to establish viral replication in the intestine, enteric viruses need to retain their infectivity in often low pH gastric fluids, and in intestinal fluids, which contain digestive enzymes and bile salts. In this study, we examined whether human coronaviruses OC43 (HCoV-OC43) can remain infectious in simulated GI fluids that models human fasting-state and fed-state, in the presence or absence of food. We demonstrated that except for fasting-state gastric fluid (pH 1.6), the virus can remain infectious in all other gastrointestinal fluids for 1 h. Furthermore, we demonstrated that presence of food could significantly improve viral survival in gastric fluids. Therefore, this study provides evidence that ingestion with food could protect the virus against inactivation by the GI fluids.

Examining the Effect of Organic Acids on Inactivation of Hepatitis E Virus.

ABSTRACT: Infection with hepatitis E virus genotype 3 (HEV-3) is an emerging cause of illness in developed countries. In North America and Europe, HEV-3 has been increasingly detected in swine, and exposure to pigs and pork products is considered the primary source of infection. We have previously demonstrated the prevalence of the HEV-3 genome in commercial pork products in Canada. In this study, we investigated the application of citric acid and acetic acid to inactivate HEV-3 on food and on food contact surfaces. For this purpose, plastic, stainless steel, and pork pâté surfaces were inoculated with HEV-3 and were treated with acetic acid or citric acid at 1, 3, or 5%. The infectivity of posttreatment viral particles was determined by cell culture. A greater than 2-log reduction in viral infectivity was observed on plastic and stainless steel treated with the organic acids, but the treatment was less effective on HEV infectivity on pork pâté (average reductions of 0.47 log citric acid and 0.63 log acetic acid). Therefore, we conclude that citric acid and acetic acid have potential application to control HEV-3 on food contact surfaces but are not suitable for food.