Seroprevalence of norovirus genogroup IV antibodies among humans, Italy, 2010-2011

Improving the Detection and Understanding of Infectious Human Norovirus in Food and Water Matrices: A Review of Methods and Emerging Models

Human norovirus (HuNoV) is a leading global cause of viral gastroenteritis, contributing to numerous outbreaks and illnesses annually. However, conventional cell culture systems cannot support the cultivation of infectious HuNoV, making its detection and study in food and water matrices particularly challenging. Recent advancements in HuNoV research, including the emergence of models such as human intestinal enteroids (HIEs) and zebrafish larvae/embryo, have significantly enhanced our understanding of HuNoV pathogenesis. This review provides an overview of current methods employed for HuNoV detection in food and water, along with their associated limitations. Furthermore, it explores the potential applications of the HIE and zebrafish larvae/embryo models in detecting infectious HuNoV within food and water matrices. Finally, this review also highlights the need for further optimization and exploration of these models and detection methods to improve our understanding of HuNoV and its presence in different matrices, ultimately contributing to improved intervention strategies and public health outcomes.

Epidemiological investigation of norovirus infections in Punjab, Pakistan, through the One Health approach

Introduction

Norovirus, mainly associated with acute gastroenteritis, is very contagious and can affect a vast range of species ranging from cattle, pigs, dogs, mice, cats, sheep, and lions to humans. It is a foodborne pathogen that mainly transmits through the fecal–oral route.

Methods

This is the first-ever study conducted in Lahore and Sheikhupura districts of Punjab, Pakistan, to investigate noroviruses through the One Health approach. From January 2020 to September 2021, 200 fecal samples were collected from clinical cases of hospitalized patients and 200 fecal samples from sick animals at veterinary hospitals and local farms. In addition, 500 food and beverage samples were collected from street vendors and retail stores. A predesigned questionnaire was used to assess the risk factors and clinical characteristics of sick people and animals.

Results and discussion

Overall, 14% of the human clinical samples were positive by RT-PCR for genogroup GII. All bovine samples were negative. Food and beverage samples were tested in pools, resulting in sugarcane juice samples positive for genogroup GII. Previous contact with acute gastroenteritis patients, sex, and presence of vomiting were found to be significant risk factors (p ≤ 0.05). The substantial number of diarrhea cases associated with noroviruses calls for additional studies to investigate the epidemiology and transmission and to improve surveillance.

Detection of antibodies against Domestic Cat Hepadnavirus using baculovirus-expressed core protein

A novel orthohepadnavirus (Domestic Cat Hepadnavirus: DCH) similar to human hepatitis B virus has been recently detected in serum and liver samples from domestic cats with chronic hepatitis and hepatocellular carcinoma. Molecular investigations by independent research groups around the world have revealed positivity rates ranging from 6.5% to 12.5% in blood samples and up to 14.0% in liver tissue. In this study, we screened an age-stratified collection of feline sera (n = 256) by using an antibody detection ELISA assay based on the recombinant core antigen of DCH (DCHc). Specific antibodies (DCHc Abs) were detected with a prevalence of 25.0%. The DNA of DCH was detected in 35.9% (23/64) of seropositive cats and only in 1.0% (2/192) of seronegative animals. Based on the serological (IgG and IgM anti-DCHc) and virological status, the possible stages of DCH infection were predicted. This article is protected by copyright. All rights reserved.

The concept of one health applied to the problem of zoonotic diseases

Zoonotic diseases are a burden on healthcare systems globally, particularly underdeveloped nations. Numerous vertebrate animals (e.g., birds, mammals and reptiles) serve as amplifier hosts or reservoirs for viral zoonoses. The spread of zoonotic disease is associated with environmental factors, climate change, animal health as well as other human activities including globalization, urbanization and travel. Diseases at the human-animal environment interface (e.g., zoonotic diseases, vector-borne diseases, food/water borne diseases) continue to pose risk to animals and humans with a great significant mortality and morbidity. It is estimated that of 1400 infectious diseases known to affect humans, 60% of them are of animal origin. In addition, 75% of the emerging infectious diseases have a zoonotic nature, worldwide. The one health concept plays an important role in the control and prevention of zoonoses by integrating animal, human, and environmental health through collaboration and communication among osteopaths, wildlife, physicians, veterinarians professionals, public health and environmental experts, nurses, dentists, physicists, biomedical engineers, plant pathologists, biochemists, and others. No one sector, organization, or person can address issues at the animal-human-ecosystem interface alone.

Age-seroprevalence curves for the multi-strain structure of influenza A virus

The relationship between age and seroprevalence can be used to estimate the annual attack rate of an infectious disease. For pathogens with multiple serologically distinct strains, there is a need to describe composite exposure to an antigenically variable group of pathogens. In this study, we assay 24,402 general-population serum samples, collected in Vietnam between 2009 to 2015, for antibodies to eleven human influenza A strains. We report that a principal components decomposition of antibody titer data gives the first principal component as an appropriate surrogate for seroprevalence; this results in annual attack rate estimates of 25.6% (95% CI: 24.1% - 27.1%) for subtype H3 and 16.0% (95% CI: 14.7% - 17.3%) for subtype H1. The remaining principal components separate the strains by serological similarity and associate birth cohorts with their particular influenza histories. Our work shows that dimensionality reduction can be used on human antibody profiles to construct an age-seroprevalence relationship for antigenically variable pathogens.

Assessment of the Impact on Human Health of the Presence of Norovirus in Bivalve Molluscs: What Data Do We Miss?

In the latest One Health ECDC EFSA technical report, Norovirus in fish and fishery products have been listed as the agent/food pair causing the highest number of strong-evidence outbreaks in the EU in 2019. This review aims to identify data gaps that must be filled in order to increase knowledge on Norovirus in bivalve molluscs, perform a risk assessment and rank the key mitigation strategies for this biological hazard, which is relevant to public health. Virologic determinations are not included in any of the food safety and process hygiene microbiologic criteria reflected in the current European regulations. In addition, the Escherichia coli-based indices of acceptable faecal contamination for primary production, as well as the food safety criteria, do not appear sufficient to indicate the extent of Norovirus contamination. The qualitative risk assessment data collected in this review suggests that bivalve molluscs present a high risk to human health for Norovirus only when consumed raw or when insufficiently cooked. On the contrary, the risk can be considered negligible when they are cooked at a high temperature, while information is still scarce for non-thermal treatments.

Rare Norovirus GIV Foodborne Outbreak, Wisconsin, USA

We report a norovirus GIV outbreak in the United States, 15 years after the last reported outbreak. During May 2016 in Wisconsin, 53 persons, including 4 food handlers, reported being ill. The outbreak was linked to individually prepared fruit consumed as a fruit salad. The virus was phylogenetically classified as a novel GIV genotype.

Norovirus Seroprevalence among Adults in the United States: Analysis of NHANES Serum Specimens from 1999-2000 and 2003-2004

Norovirus is the most common cause of epidemic and endemic acute gastroenteritis. However, national estimates of the infection burden are challenging. This study used a nationally representative serum bank to estimate the seroprevalence to five norovirus genotypes including three GII variants: GI.1 Norwalk, GI.4, GII.3, GII.4 US95/96, GII.4 Farmington Hills, GII.4 New Orleans, and GIV.1 in the USA population (aged 16 to 49 years). Changes in seroprevalence to the three norovirus GII.4 variants between 1999 and 2000, as well as 2003 and 2004, were measured to examine the role of population immunity in the emergence of pandemic GII.4 noroviruses. The overall population-adjusted seroprevalence to any norovirus was 90.0% (1999 to 2000) and 95.9% (2003 to 2004). Seroprevalence was highest to GI.1 Norwalk, GII.3, and the three GII.4 noroviruses. Seroprevalence to GII.4 Farmington Hills increased significantly between the 1999 and 2000, as well as the 2003 and 2004, study cycles, consistent with the emergence of this pandemic strain. Seroprevalence to GII.4 New Orleans also increased over time, but to a lesser degree. Antibodies against the GIV.1 norovirus were consistently detected (population-adjusted seroprevalence 19.1% to 25.9%), with rates increasing with age. This study confirms the high burden of norovirus infection in US adults, with most adults having multiple norovirus infections over their lifetime.

Feline Virome-A Review of Novel Enteric Viruses Detected in Cats

Recent advances in the diagnostic and metagenomic investigations of the feline enteric environment have allowed the identification of several novel viruses that have been associated with gastroenteritis in cats. In the last few years, noroviruses, kobuviruses, and novel parvoviruses have been repetitively detected in diarrheic cats as alone or in mixed infections with other pathogens, raising a number of questions, with particular regards to their pathogenic attitude and clinical impact. In the present article, the current available literature on novel potential feline enteric viruses is reviewed, providing a meaningful update on the etiology, epidemiologic, pathogenetic, clinical, and diagnostic aspects of the infections caused by these pathogens.

Animals as Reservoir for Human Norovirus

Norovirus is the most common cause of non-bacterial gastroenteritis and is a burden worldwide. The increasing norovirus diversity is currently categorized into at least 10 genogroups which are further classified into more than 40 genotypes. In addition to humans, norovirus can infect a broad range of hosts including livestock, pets, and wild animals, e.g., marine mammals and bats. Little is known about norovirus infections in most non-human hosts, but the close genetic relatedness between some animal and human noroviruses coupled with lack of understanding where newly appearing human norovirus genotypes and variants are emerging from has led to the hypothesis that norovirus may not be host restricted and might be able to jump the species barrier. We have systematically reviewed the literature to describe the diversity, prevalence, and geographic distribution of noroviruses found in animals, and the pathology associated with infection. We further discuss the evidence that exists for or against interspecies transmission including surveillance data and data from in vitro and in vivo experiments.

Genomics Analyses of GIV and GVI Noroviruses Reveal the Distinct Clustering of Human and Animal Viruses

Noroviruses are highly diverse viruses that are the major viral cause of acute gastroenteritis in humans. Although these viruses can infect multiple mammalian species, their potential for zoonosis is not well understood, especially within Genogroup IV (GIV), which contains viruses that infect humans, canines, and felines. The study of GIV viruses has been, in part, hindered by the limited number of complete genomes. Here, we developed a full-genome amplicon-based platform that facilitated the sequencing of canine noroviruses circulating in the United States. Eight novel nearly full-length canine norovirus genomes and two nearly complete VP1 sequences, including four GIV.2, three GVI.1, and three GVI.2 viruses, were successfully obtained. Only animal strains exhibited GVI/GIV chimeric viruses, demonstrating restrictions in norovirus recombination. Using genomic, phylogenetic, and structural analyses, we show that differences within the major capsid protein and the non-structural proteins of GIV and GVI noroviruses could potentially limit cross-species transmission between humans, canines, and felines.

Seroprevalence for norovirus genogroups GII and GIV in captive non-human primates

Noroviruses (NoVs) are a major cause of epidemic gastroenteritis in children and adults. Several pieces of evidence suggest that viruses genetically and antigenically closely related to human NoVs might infect animals, raising public health concerns about potential cross-species transmission. The natural susceptibility of non-human primates (NPHs) to human NoV infections has already been reported, but a limited amount of data is currently available. In order to start filling this gap, we screened a total of 86 serum samples of seven different species of NPHs housed at the Zoological Garden (Bioparco) of Rome (Italy), collected between 2001 and 2017, using an enzyme-linked immunosorbent assay (ELISA) based on virus-like particles (VLPs) of human GII.4 and GIV.1 NoVs. Antibodies specific for both genotypes were detected with an overall prevalence of 32.6%. In detail, IgG antibodies against GII.4 NoVs were found in 18 Japanese macaques (29.0%, 18/62), a mandrill (10.0%, 1/10), a white-crowned mangabey (16.6%, 1/6) and in an orangutan (33.3%, 1/3). Twelve macaques (19.3%, 12/62), five mandrills (50.0%, 5/10), two chimpanzees (100%, 2/2) and a white-crowned mangabey (16.6%, 1/6) showed antibodies for GIV.1 NoVs. The findings of this study confirm the natural susceptibility of captive NHPs to GII NoV infections. In addition, IgG antibodies against GIV.1 were detected, suggesting that NHPs are exposed to GIV NoVs or to antigenically related NoV strains.

Seroprevalence of sapovirus in dogs using baculovirus-expressed virus-like particles

Caliciviruses of the Sapovirus genus have been recently detected in dogs. Canine sapoviruses (SaVs) have been identified in the stools of young or juvenile animals with gastro-enteric disease at low prevalence (2.0-2.2%), but whether they may have a role as enteric pathogens and to which extent dogs are exposed to SaVs remains unclear. Here, we report the expression in a baculovirus system of virus like-particles (VLPs) of a canine SaV strain, the prototype virus Bari/4076/2007/ITA. The recombinant antigen was used to develop an enzyme-linked immunosorbent assay (ELISA). By screening an age-stratified collection of serum samples from 516 dogs in Italy, IgG antibodies specific for the canine SaV VLPs were detected in 40.3% (208/516) of the sera. Also, as observed for SaV infection in humans, we observed a positive association between seropositivity and age, with the highest prevalence rates in dogs older than 4 years of age.

Bat Caliciviruses and Human Noroviruses Are Antigenically Similar and Have Overlapping Histo-Blood Group Antigen Binding Profiles

Emerging zoonotic viral diseases remain a challenge to global public health. Recent surveillance studies have implicated bats as potential reservoirs for a number of viral pathogens, including coronaviruses and Ebola viruses. Caliciviridae represent a major viral family contributing to emerging diseases in both human and animal populations and have been recently identified in bats. In this study, we blended metagenomics, phylogenetics, homology modeling, and in vitro assays to characterize two novel bat calicivirus (BtCalV) capsid sequences, corresponding to strain BtCalV/A10/USA/2009, identified in Perimyotis subflavus near Little Orleans, MD, and bat norovirus. We observed that bat norovirus formed virus-like particles and had epitopes and receptor-binding patterns similar to those of human noroviruses. To determine whether these observations stretch across multiple bat caliciviruses, we characterized a novel bat calicivirus, BtCalV/A10/USA/2009. Phylogenetic analysis revealed that BtCalV/A10/USA/2009 likely represents a novel Caliciviridae genus and is most closely related to "recoviruses." Homology modeling revealed that the capsid sequences of BtCalV/A10/USA/2009 and bat norovirus resembled human norovirus capsid sequences and retained host ligand binding within the receptor-binding domains similar to that seen with human noroviruses. Both caliciviruses bound histo-blood group antigens in patterns that overlapped those seen with human and animal noroviruses. Taken together, our results indicate the potential for bat caliciviruses to bind histo-blood group antigens and overcome a significant barrier to cross-species transmission. Additionally, we have shown that bat norovirus maintains antigenic epitopes similar to those seen with human noroviruses, providing further evidence of evolutionary descent. Our results reiterate the importance of surveillance of wild-animal populations, especially of bats, for novel viral pathogens.IMPORTANCE Caliciviruses are rapidly evolving viruses that cause pandemic outbreaks associated with significant morbidity and mortality globally. The animal reservoirs for human caliciviruses are unknown; bats represent critical reservoir species for several emerging and zoonotic diseases. Recent reports have identified several bat caliciviruses but have not characterized biological functions associated with disease risk, including their potential emergence in other mammalian populations. In this report, we identified a novel bat calicivirus that is most closely related to nonhuman primate caliciviruses. Using this new bat calicivirus and a second norovirus-like bat calicivirus capsid gene sequence, we generated virus-like particles that have host carbohydrate ligand binding patterns similar to those of human and animal noroviruses and that share antigens with human noroviruses. The similarities to human noroviruses with respect to binding patterns and antigenic epitopes illustrate the potential for bat caliciviruses to emerge in other species and the importance of pathogen surveillance in wild-animal populations.

New viruses associated with canine gastroenteritis

A number of novel viruses have been associated with canine gastroenteritis in recent years, from viral families as diverse as Caliciviridae and Picornaviridae to Parvoviridae and Circoviridae. The ability of many of these viruses to cause disease is uncertain, but epidemiological studies are continually adding to our knowledge of these potential pathogens. This review presents a summary of the latest research and current understanding of novel viruses associated with canine gastroenteritis.

Seroprevalence for norovirus genogroup II, IV and VI in dogs

Molecular and serological data suggest that noroviruses (NoVs) might be transmitted between humans and domestic carnivores. In this study we screened an age-stratified collection of canine sera (n=516) by using an ELISA assay based on virus-like particles (VLPs) of human NoVs GII.4 and GIV.1 and carnivore NoVs GIV.2 and GVI.2. Antibodies against GII.4 and GIV.1 human NoVs and GIV.2 and GVI.2 NoVs from carnivores were identified in dog sera (13.0%, 67/516) suggesting their exposure to homologous and heterologous NoVs. Analysis of the trends of age-class prevalence showed a gradual increase in the positive rate from 9.0% and 7.0%, in young dogs <1year of age to 15.0% in dogs older than 12 years, for GII.4 and GVI.2 NoVs, respectively. A significant difference in the IgG distribution by age classes was observed for GIV.1 NoVs, with the highest rate of antibodies (7.0%) in the age group <1year and the lowest (1.0%) in the age-classes 7-9 (P=0.049). High correlation between the reactivity to GII.4 and GVI.2 NoVs was observed, likely due to conserved epitopes in the capsid structure.

Norovirus genetic diversity and evolution: implications for antiviral therapy

Human noroviruses are the leading cause of foodborne illness causing both acute and chronic gastroenteritis. In recent years, a number of vaccine candidates entered (pre-) clinical development and the first efforts to develop antiviral therapy have been made. We here discuss aspects of norovirus genetic evolution, persistence in immunocompromised patients as well as the risk and potential consequences of resistance development toward future antiviral drugs.

Occurrence of Norovirus GIV in Environmental Water Samples from Belém City, Amazon Region, Brazil

Noroviruses are the major cause of non-bacterial acute gastroenteritis outbreaks in humans, with few reports about the occurrence of the norovirus GIV strain. We investigated the presence of norovirus GIV in surface water (river, bay, and stream) and untreated sewage, and we determined a positivity rate of 9.4% (9/96). The strains genotyped were GIV.1. To our knowledge, this is the first report of GIV in Brazil.

A novel feline norovirus in diarrheic cats

By screening a collection of fecal samples from young cats housed in three different shelters in South Italy, noroviruses (NoVs) were found in 3/48 (6.2%) specimens of animals with enteritis signs while they were not detected in samples collected from healthy cats (0/57). Upon sequence analysis of the short RNA-dependent RNA polymerase (RdRp) region, the three strains displayed the highest nucleotide (nt) and amino acid (aa) identities to the prototype GIV.2 strain lion/Pistoia/387/06/ITA (91.0–93.0% nt and 97.0–98.0% aa). The sequence of ~ 3.4-kb portion at the 3′ end of the genome of a NoV strain, TE/77-13/ITA, was determined. In the full-length ORF2, encoding the VP1 capsid protein, the virus was genetically closest to the canine GVI.2 NoV strains C33/Viseu/2007/PRT and FD53/2007/ITA (81.0–84.0% nt and 93.0–94.0% aa identities), suggesting a recombination nature, with the cross-over site being mapped to the ORF1-ORF2 junction. Based on the full-length VP1 amino acid sequence, we classified the novel feline NoV, together with the canine strains Viseu and FD53, as a genotype 2, within the genogroup GVI. These findings indicate that, as observed for GIV NoV, GVI strains may infect both the canine and feline host. Unrestricted circulation of NoV strains in small carnivores may provide the basis for quick genetic diversification of these viruses by recombination. Interspecies circulation of NoVs in pets must also be considered when facing outbreaks of enteric diseases in these animals.

•

GIV and GVI NoVs have been recently found in domestic carnivores.

•

In this study, NoV strains resembling animal GIV.2 NoVs in their polymerase region were detected in diarrheic cats.

•

One Italian strain, TE/77-13/ITA, in the full-length VP1 sequence shared the highest identity to the canine GVI.2 NoVs.

Bovine noroviruses: A missing component of calf diarrhoea diagnosis

Noroviruses are RNA viruses that belong to the Genus Norovirus, Family Caliciviridae, and infect human beings and several animal species, including cattle. Bovine norovirus infections have been detected in cattle of a range of different ages throughout the world. Currently there is no suitable cell culture system for these viruses and information on their pathogenesis is limited. Molecular and serological tests have been developed, but are complicated by the high genetic and antigenic diversity of bovine noroviruses. Bovine noroviruses can be detected frequently in faecal samples of diarrhoeic calves, either alone or in association with other common enteric pathogens, suggesting a role for these viruses in the aetiology of calf enteritis.

Antibodies for strain 2117-like vesiviruses (caliciviruses) in humans

The vesivirus strain 2117 has been identified as contaminant of bioreactors used for production of human drugs, due to possible contamination of the reagents used for cell cultivation. Using an ELISA assay, antibodies specific for 2117-like viruses were detected in 32/410 (7.8%) human sera, indicating exposure to these viruses.

Multiplex real-time RT-PCR for the simultaneous detection and quantification of GI, GII and GIV noroviruses

Noroviruses are important causes of acute gastroenteritis and are classified into six genogroups with GI, GII and GIV containing human pathogens. This high genetic diversity represents a significant challenge for diagnostic assay development. Genogroup specific monoplex and multiplex real time RT-PCR assays are widely used for the detection of GI and GII noroviruses. On the other hand, GIV norovirus detection is not part of routine laboratory diagnosis. This study describes the development and evaluation of a one tube, real time RT-PCR assay for the simultaneous detection and quantification of GI, GII and GIV noroviruses, including both GIV.1 (human) and GIV.2 (animal) strains. Assay performance was evaluated on a panel of norovirus positive clinical samples by comparison of monoplex and multiplex standard curves and Ct values. The multiplex assay demonstrated equal sensitivity and specificity to the monoplex assays and was able to detect all GI, GII and GIV noroviruses with Ct values equal to that of the monoplex assays. The multiplex assay described in this study will be instrumental for the better understanding of GIV norovirus epidemiology, including their possible zoonotic nature.

Detection of feline kobuviruses in diarrhoeic cats, Italy

•

Kobuviruses were found in cats with diarrhoea.

•

Kobuviruses were not detected in asymptomatic cats.

•

The complete genome sequence of one such strains was determined.

•

Kobuviruses resembling the newly described feline kobuviruses were identified.

•

First evidence on the circulation of feline kobuviruses outside the Asian continent.

Kobuviruses have been identified in the enteric tract of several mammalian species but their role as enteric pathogens is still not defined. In this study, feline kobuviruses were found in 13.5% of cats with diarrhoea, but not in asymptomatic animals. In the full-length genome, one such strains, TE/52/13/ITA, displayed the highest nucleotide identity (96.0%) to the prototype strain FK-13. These results provide firm evidence that kobuviruses are common constituents of feline enteric viroma and that they are not geographically restricted to the Asian continent, where they were first signalled.