High Prevalence and Diversity of Caliciviruses in a Community Setting Determined by a Metagenomic Approach.

We recently carried out a metagenomic study to determine the fecal virome of infants during their first year of life in a semirural community in Mexico. A total of 97 stool samples from nine children were collected starting 2 weeks after birth and monthly thereafter until 12 months of age. In this work, we describe the prevalence and incidence of caliciviruses in this birth cohort. We found that 54 (56%) and 24 (25%) of the samples were positive for norovirus and sapovirus sequence reads detected by next-generation sequencing, respectively. Potential infections were arbitrarily considered when at least 20% of the complete virus genome was determined. Considering only these samples, there were 3 cases per child/year for norovirus and 0.33 cases per child/year for sapovirus. All nine children had sequence reads related to norovirus in at least 2 and up to 10 samples, and 8 children excreted sapovirus sequence reads in 1 and up to 5 samples during the study. The virus in 35 samples could be genotyped. The results showed a high diversity of both norovirus (GI.3[P13], GI.5, GII.4, GII.4[P16], GII.7[P7], and GII.17[P17]) and sapovirus (GI.1, GI.7, and GII.4) in the community. Of interest, despite the frequent detection of caliciviruses in the stools, all children remained asymptomatic during the study. Our results clearly show that metagenomic studies in stools may reveal a detailed picture of the prevalence and diversity of gastrointestinal viruses in the human gut during the first year of life. IMPORTANCE Human caliciviruses are important etiological agents of acute gastroenteritis in children under 5 years of age. Several studies have characterized their association with childhood diarrhea and their presence in nondiarrheal stool samples. In this work, we used a next-generation sequencing approach to determine, in a longitudinal study, the fecal virome of infants during their first year of life. Using this method, we found that caliciviruses can be detected significantly more frequently than previously reported, providing a more detailed picture of the prevalence and genetic diversity of these viruses in the human gut during early life.

Comparison of gut viral communities in diarrhoea and healthy dairy calves.

Calf diarrhoea has been a major cause of economic losses in the global dairy industry. Many factors, including multiple pathogen infections, can directly or indirectly cause calf diarrhoea. This study compared the faecal virome between 15 healthy calves and 15 calves with diarrhoea. Significantly lower diversity of viruses was found in samples from animals with diarrhoea than those in the healthy ones, and this feature may also be related to the age of the calves. Viruses belonging to the families Astroviridae and Caliciviridae that may cause diarrhoea in dairy calves have been characterized, which revealed that reads of caliciviruses and astroviruses in diarrhoea calves were much higher than those in healthy calves. Five complete genomic sequences closely related to Smacoviridae have been identified, which may participate in the regulation of the gut virus community ecology of healthy hosts together with bacteriophages. This research provides a theoretical basis for further understanding of known or potential enteric pathogens related to calf diarrhoea.

Development of an EvaGreen based real-time RT-PCR assay for rapid detection, quantitation and diagnosis of goose calicivirus.

An unclassified calicivirus (CV) detected in geese was recently reported and proposed as a new member of the family Caliciviridae. There is limited information about the epidemiology, etiology and detection method of goose-origin CV (GCV) to date. In this study, an EvaGreen based fluorescence quantitative real-time RT-PCR assay was developed and optimized for the detection of GCVs. The assay sensitively detected GCV RNA template with a good linear standard curve. We also demonstrated the specificity and reproducibility of the detection method for GCVs. Thus, the method developed in this study will benefit the investigation of possible sporadic outbreaks of CV infections in geese, as well as epidemiological and etiological studies of GCVs.

ICTV Virus Taxonomy Profile: Caliciviridae.

The family Caliciviridae includes viruses with single-stranded, positive-sense RNA genomes of 7.4-8.3 kb. The most clinically important representatives are human noroviruses, which are a leading cause of acute gastroenteritis in humans. Virions are non-enveloped with icosahedral symmetry. Members of seven genera infect mammals (Lagovirus, Norovirus, Nebovirus, Recovirus, Sapovirus, Valovirus and Vesivirus), members of two genera infect birds (Bavovirus and Nacovirus), and members of two genera infect fish (Minovirus and Salovirus). This is a summary of the International Committee on Taxonomy of Viruses (ICTV) Report on the family Caliciviridae, which is available at ictv.global/report/caliciviridae.

Caliciviridae Other Than Noroviruses.

Besides noroviruses, the Caliciviridae family comprises four other accepted genera: Sapovirus, Lagovirus, Vesivirus, and Nebovirus. There are six new genera proposed: Recovirus, Valovirus, Bavovirus, Nacovirus, Minovirus, and Salovirus. All Caliciviridae have closely related genome structures, but are genetically and antigenically highly diverse and infect a wide range of mammalian host species including humans. Recombination in nature is not infrequent for most of the Caliciviridae, contributing to their diversity. Sapovirus infections cause diarrhoea in pigs, humans and other mammalian hosts. Lagovirus infections cause systemic haemorrhagic disease in rabbits and hares, and vesivirus infections lead to lung disease in cats, vesicular disease in swine, and exanthema and diseases of the reproductive system in large sea mammals. Neboviruses are an enteric pathogen of cattle, differing from bovine norovirus. At present, only a few selected caliciviruses can be propagated in cell culture (permanent cell lines or enteroids), and for most of the cultivatable caliciviruses helper virus-free, plasmid only-based reverse genetics systems have been established. The replication cycles of the caliciviruses are similar as far as they have been explored: viruses interact with a multitude of cell surface attachment factors (glycans) and co-receptors (proteins) for adsorption and penetration, use cellular membranes for the formation of replication complexes and have developed mechanisms to circumvent innate immune responses. Vaccines have been developed against lagoviruses and vesiviruses, and are under development against human noroviruses.

Investigation of the viral and bacterial microbiota in intestinal samples from mink (Neovison vison) with pre-weaning diarrhea syndrome using next generation sequencing.

Pre-weaning diarrhea (PWD) in mink kits is a common multifactorial syndrome on commercial mink farms. Several potential pathogens such as astroviruses, caliciviruses, Escherichia coli and Staphylococcus delphini have been studied, but the etiology of the syndrome seems complex. In pooled samples from 38 diarrheic and 42 non-diarrheic litters, each comprising of intestinal contents from 2-3 mink kits from the same litter, the bacterial populations were studied using Illumina Next Generation Sequencing technology and targeted 16S amplicon sequencing. In addition, we used deep sequencing to determine and compare the viral intestinal content in 31 healthy non-diarrheic and 30 diarrheic pooled samples (2-3 mink kits from the same litter per pool). The results showed high variations in composition of the bacterial species between the pools. Enterococci, staphylococci and streptococci dominated in both diarrheic and non-diarrheic pools. However, enterococci accounted for 70% of the reads in the diarrheic group compared to 50% in the non-diarrheic group and this increase was at the expense of staphylococci and streptococci which together accounted for 45% and 17% of the reads in the non-diarrheic and diarrheic group, respectively. Moreover, in the diarrheic pools there were more reads assigned to Clostridia, Escherichia-Shigella and Enterobacter compared to the non-diarrheic pools. The taxonomically categorized sequences from the virome showed that the most prevalent viruses in all pools were caliciviruses and mamastroviruses (almost exclusively type 10). However, the numbers of reads assigned to caliciviruses were almost 3 times higher in the diarrheic pools compared the non-diarrheic pools and Sapporo-like caliciviruses were more abundant than the Norwalk-like caliciviruses. The results from this study have contributed to the insight into the changes in the intestinal microbiota associated with the PWD syndrome of mink.

First complete genome sequence of a European non-pathogenic rabbit calicivirus (lagovirus GI.3).

We report the full genome sequence of the non-pathogenic rabbit lagovirus Lagovirus europaeus/GI.3/O cun/FR/2006/06-11 (GI.3/06-11), collected from a healthy French domestic rabbit in 2006, and initially described as 06-11 strain. The sequence reveals a genomic organization similar to lagoviruses. It was 7,436 bases long and contained two open reading frames (ORF). A dipeptide variation at the potential p23/2C-like helicase cleavage site (EE instead of ED) was observed, a feature only shared with non-recombinant pathogenic lagoviruses in GI.2 and with two European brown hare syndrome viruses (EBHSV) collected in 1982 in Sweden. GI.3/06-11 has only one initiation codon at the beginning of the ORF2 like the avirulent Italian rabbit calicivirus (RCV) and EBHSV. Previous genetic analyses based on the capsid gene sequences showed that GI.3/06-11 was closer to the RCV and pathogenic lagoviruses GI.1 strains than other lagoviruses. This study, by revealing that GI.3/06-11 genome sequence significantly clustered with pathogenic GI.2 strains, gives prominence of new genetic relationship among lagoviruses and should contribute to understand the emergence of pathogenic strains.

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.

Genomic characterization of a RdRp-recombinat nebovirus strain with a novel VP1 genotype.

Nebovirus is a new genus within the family Caliciviridae and is a causative agent of calf diarrhea. The limited nebovirus genomic sequences that are currently available has hampered understanding of nebovirus genetic evolution. The aim of the present study was to determine the genomic characterization of strain Bo/LZB-1/17/CH, which was previously identified as being similar to the novel genotype strain Bo/DijonA216/06/FR based on partial capsid sequences. Our results show that the complete RNA genome of strain Bo/LZB-1/17/CH is 7453 nucleotides (nt) in length and shares 79.0%-83.5% nt identity with all available nebovirus genomes in the GenBank database. A phylogenetic analysis based on its complete genome sequence revealed that strain Bo/LZB-1/17/CH clustered into an independent branch. Two interesting characteristics were observed in the genome of strain Bo/LZB-1/17/CH. First, the major capsid protein (VP1) of strain Bo/LZB-1/17/CH shares 96.6% amino acid (aa) identity with strain Bo/DijonA216/06/FR but shares only 75.2%-76.8% aa identity with other nebovirus strains and has an even lower identity in the P2 domain (61.1%-65% aa identity). Second, the RNA-dependent RNA polymerase (RdRp) of strain Bo/LZB-1/17/CH is more closely related to NB-like strains than it is to strain Bo/DijonA216/06/FR, and a recombination event was identified within the 3' end of the RdRp in strain Bo/LZB-1/17/CH. In conclusion, the results in this study indicate that strain Bo/LZB-1/17/CH may represent a novel nebovirus strain. To the best of our knowledge, this is the first description of a recombinant event in nebovirus RdRp.

Metagenomic analysis of the RNA fraction of the fecal virome indicates high diversity in pigs infected by porcine endemic diarrhea virus in the United States.

BACKGROUND: Emergence and re-emergence of porcine epidemic diarrhea virus (PEDV) in North America, Asia and Europe has caused severe economic loss to the global swine industry. However, the virome of PEDV infected pigs and its effect on disease severity remains unknown. The advancements of sequencing technology have made it possible to characterize the entire microbiome of different body sites for any host. METHODS: The objective of this study was to characterize the RNA virome in PEDV-positive pigs using the hypothesis-free metagenomics approach based on next-generation sequencing. Specifically, 217 PEDV-positive swine fecal swab samples collected from diarrheic piglets over 17 US states during 2015-2016 were analyzed. RESULTS: A Kraken algorithm-based bioinformatics analysis revealed the presence of up to 9 different RNA genera besides PEDV (Alphacoronavirus genus), including Mamastrovirus (52%, 113/217), Enterovirus (39%, 85/217), Sapelovirus (31%, 67/217), Posavirus (30%, 66/217), Kobuvirus (23%, 49/217), Sapovirus (13%, 28/217), Teschovirus (10%, 22/217), Pasivirus (9%, 20/217), and Deltacoronavirus (3%, 6/217). There were 58 out of 217 piglets (27%) have PEDV infection alone whereas the remaining 159 (73%) shed 2 up to 9 different viruses. CONCLUSION: These findings demonstrated that PEDV infected diarrheic pigs had an extensive RNA viral flora consisting of four different families: Astroviridae, Picornaviridae, Caliciviridae, and Coronaviridae.

First detection of Nebovirus and Norovirus from cattle in China.

Neboviruses and genogroup III noroviruses (NoVsGIII) are causative agents of calf diarrhea. The purpose of this study was to investigate the presence of neboviruses and noroviruses in cattle in China. Twenty-eight diarrhea fecal samples collected from 5 different farms were analyzed by RT-PCR. The results showed that 3 nebovirus positive samples were detected on 2 farms, with two strains being related to Bo/DijonA216/06/FR strain and the other one clustering with NB-like strains. Meanwhile, 3 norovirus positive samples were detected on 3 farms, all of which belonged to genotype 1. Our results confirmed the presence of neboviruses and NoVsGIII in China for the first time, and supported the presence of a novel "DijonA216-like" nebovirus genotype.

Genomic characterization of a novel calicivirus, FHMCV-2012, from baitfish in the USA.

During regulatory sampling of fathead minnows (Pimephales promelas), a novel calicivirus was isolated from homogenates of kidney and spleen inoculated into bluegill fry (BF-2) cells. Infected cell cultures exhibiting cytopathic effects were screened by PCR-based methods for selected fish viral pathogens. Illumina HiSeq next generation sequencing of the total RNA revealed a novel calicivirus genome that showed limited protein sequence similarity to known homologs in a BLASTp search. The complete genome of this fathead minnow calicivirus (FHMCV) is 6564 nt long, encoding a polyprotein of 2114 aa in length. The complete polyprotein shared only 21% identity with Atlantic salmon calicivirus,followed by 11% to 14% identity with mammalian caliciviruses. A molecular detection assay (RT-PCR) was designed from this sequence for screening of field samples for FHMCV in the future. This virus likely represents a prototype species of a novel genus in the family Caliciviridae, tentatively named "Minovirus".

Genetic characterization of a novel calicivirus from a goose.

A novel calicivirus (strain H146) was detected in a goose and sequenced. The H146 genome consisted of two open reading frames (ORFs) with an 8-nucleotide (nt) overlap between the two ORFs, similar to what has been found in the bat sapovirus TLC58. The virus was most closely related to nacoviruses when comparing the complete genome sequence (49% identity), non-structural region (NS; 31-34% amino acid [aa] sequence identity), and major structural VP1 region (28-30% aa identity), whereas both goose calicivirus N and feline calicivirus were the closest relatives of H146 in the VP2 region (20% aa sequence identity). The levels of divergence between H146 and its closest relatives in different genomic regions are comparable to those between some members of different genera. Phylogenetic analysis based on the NS and VP1 amino acid sequences clearly demonstrated that H146 formed a separate clade. Thus, calicivirus H146 was identified as a founding member of a novel genus for which we propose the name "Sanovirus".

Caliciviruses in hospitalized children, São Luís, Maranhão, 1997-1999: detection of norovirus GII. 12

ABSTRACT Gastroenteritis is one of the most common diseases during childhood, with norovirus (NoV) and sapovirus (SaV) being two of its main causes. This study reports for the first time the incidence of these viruses in hospitalized children with and without gastroenteritis in São Luís, Maranhão. A total of 136 fecal samples were tested by enzyme immunoassays (EIA) for the detection of NoV and by reverse transcription-polymerase chain reaction (RT-PCR) for detection of both NoV and SaV. Positive samples for both agents were subjected to sequencing. The overall frequency of NoV as detected by EIA and RT-PCR was 17.6% (24/136) and 32.6% (15/46), respectively in diarrheic patients and 10.0% (9/90) in non-diarrheic patients (p < 0.01). Of the diarrheic patients, 17% had fever, vomiting and anorexia, and 13% developed fever, vomiting and abdominal pain. Of the 24 NoV-positive samples, 50% (12/24) were sequenced and classified as genotypes GII.3 (n = 1), GII.4 (6), GII.5 (1), GII.7 (2), GII.12 (1) and GII.16 (1). SaV frequency was 9.8% (11/112), with 22.6% (7/31) in diarrheic patients and 4.9% (4/81) in nondiarrheic (p = 0.04) ones. In diarrheic cases, 27.3% had fever, vomiting and anorexia, whereas 18.2% had fever, anorexia and abdominal pain. One SaV-positive sample was sequenced and classified as GII.1. These results show a high genetic diversity of NoV and higher prevalence of NoV compared to SaV. Our data highlight the importance of NoV and SaV as enteropathogens in São Luís, Maranhão.

Caliciviruses in hospitalized children, São Luís, Maranhão, 1997-1999: detection of norovirus GII.12.

Gastroenteritis is one of the most common diseases during childhood, with norovirus (NoV) and sapovirus (SaV) being two of its main causes. This study reports for the first time the incidence of these viruses in hospitalized children with and without gastroenteritis in São Luís, Maranhão. A total of 136 fecal samples were tested by enzyme immunoassays (EIA) for the detection of NoV and by reverse transcription-polymerase chain reaction (RT-PCR) for detection of both NoV and SaV. Positive samples for both agents were subjected to sequencing. The overall frequency of NoV as detected by EIA and RT-PCR was 17.6% (24/136) and 32.6% (15/46), respectively in diarrheic patients and 10.0% (9/90) in non-diarrheic patients (p<0.01). Of the diarrheic patients, 17% had fever, vomiting and anorexia, and 13% developed fever, vomiting and abdominal pain. Of the 24 NoV-positive samples, 50% (12/24) were sequenced and classified as genotypes GII.3 (n=1), GII.4 (6), GII.5 (1), GII.7 (2), GII.12 (1) and GII.16 (1). SaV frequency was 9.8% (11/112), with 22.6% (7/31) in diarrheic patients and 4.9% (4/81) in nondiarrheic (p=0.04) ones. In diarrheic cases, 27.3% had fever, vomiting and anorexia, whereas 18.2% had fever, anorexia and abdominal pain. One SaV-positive sample was sequenced and classified as GII.1. These results show a high genetic diversity of NoV and higher prevalence of NoV compared to SaV. Our data highlight the importance of NoV and SaV as enteropathogens in São Luís, Maranhão.

Sequencing and molecular modeling identifies candidate members of Caliciviridae family in bats.

Emerging viral diseases represent an ongoing challenge for globalized world and bats constitute an immense, partially explored, reservoir of potentially zoonotic viruses. Caliciviruses are important human and animal pathogens and, as observed for human noroviruses, they may impact on human health on a global scale. By screening fecal samples of bats in Hungary, calicivirus RNA was identified in the samples of Myotis daubentonii and Eptesicus serotinus bats. In order to characterize more in detail the bat caliciviruses, large portions of the genome sequence of the viruses were determined. Phylogenetic analyses and molecular modeling identified firmly the two viruses as candidate members within the Caliciviridae family, with one calicivirus strain resembling members of the Sapovirus genus and the other bat calicivirus being more related to porcine caliciviruses of the proposed genus Valovirus. This data serves the effort for detecting reservoir hosts for potential emerging viruses and recognize important evolutionary relationships.

Farm-level prevalence and risk factors for detection of hepatitis E virus, porcine enteric calicivirus, and rotavirus in Canadian finisher pigs.

Hepatitis E virus (HEV), norovirus (NoV), and rotavirus (RV) are all hypothesized to infect humans zoonotically via exposure through swine and pork. Our study objectives were to estimate Canadian farm-level prevalence of HEV, NoV [specifically porcine enteric calicivirus (PEC)], and RV in finisher pigs, and to study risk factors for farm level viral detection. Farms were recruited using the Canadian Integrated Program for Antimicrobial Resistance Surveillance (CIPARS) and FoodNet Canada on-farm sampling platforms. Six pooled groups of fecal samples were collected from participating farms, and a questionnaire capturing farm management and biosecurity practices was completed. Samples were assayed using validated real-time polymerase chain reaction (RT-PCR). We modeled predictors for farm level viral RNA detection using logistic and exact logistic regression. Seventy-two herds were sampled: 51 CIPARS herds (15 sampled twice) and 21 FoodNet Canada herds (one sampled twice). Hepatitis E virus was detected in 30/88 farms [34.1% (95% CI 25.0%, 44.5%)]; PEC in 18 [20.5% (95% CI: 13.4%, 30.0%)], and RV in 6 farms [6.8% (95% CI: 3.2%, 14.1%)]. Farm-level prevalence of viruses varied with province and sampling platform. Requiring shower-in and providing boots for visitors were significant predictors (P < 0.05) in single fixed effect mixed logistic regression analysis for detection of HEV and PEC, respectively. In contrast, all RV positive farms provided boots and coveralls, and 5 of 6 farms required shower-in. We hypothesized that these biosecurity measures delayed the mean age of RV infection, resulting in an association with RV detection in finishers. Obtaining feeder pigs from multiple sources was consistently associated with greater odds of detecting each virus.

Le virus de l'hépatite E (VHE), le norovirus (NoV), et le rotavirus (RV) sont tous suspectés être des agents zoonotiques associés à une exposition aux porcs ou à la viande de porc. Les objectifs de la présente étude étaient d'estimer, dans des fermes canadiennes, la prévalence de VHE, NoV [spécifiquement le calicivirus entérique porcin (CEP)], et le RV chez des porcs en finition, et d'étudier les facteurs de risque pour la détection virale à la ferme. Les fermes ont été recrutées à l'aide des plateformes d'échantillonnage à la ferme du Programme intégré canadien de surveillance de la résistance aux antimicrobiens (PICRA) et de FoodNet Canada. Six groupes d'échantillons amalgamés de matières fécales ont été récoltés dans les fermes participantes, et un questionnaire relevant les pratiques de gestion à la ferme et les mesures de biosécurité a été complété. Les échantillons ont été analysés au moyen d'une méthode validée de réaction d'amplification en chaîne par la polymérase en temps réel (RT-PCR). Des prédicteurs de détection de l'ARN viral sur la ferme ont été modélisés à l'aide de régressions logistiques et de régressions logistiques exactes. Soixante-douze troupeaux ont été échantillonnés : 51 troupeaux du programme CRIPA (15 troupeaux échantillonnés deux fois) et 21 troupeau du programme FoodNet Canada (un troupeau échantillonné deux fois). Le VHE a été détecté dans 30/88 fermes [34,1 % (IC 95 % : 25,0 %, 44,5 %)], CEP dans 18 [20,5 % (IC 95 % : 13,4 %, 30,0 %)], et RV dans 6 fermes [6,8 % (IC 95 % : 3,2 %, 14,1 %)]. La prévalence des virus dans les fermes variait selon la province et la plate-forme d'échantillonnage. Une douche obligatoire avant l'entrée dans la porcherie et le fait de fournir des bottes aux visiteurs s'avéraient des prédicteurs significatifs (P < 0,05) pour la détection du VHE et du CEP, respectivement, dans une analyse par régression logistique mixte à effet fixe unique. Ceci contrastait avec le fait que toutes les fermes positives pour RV fournissaient des bottes et des couvre-tout, et 5 des 6 fermes exigeaient une douche à l'entrée. Nous émettons l'hypothèse que ces mesures de biosécurité ont retardé l'âge moyen d'une infection par le RV, ce qui résultait en une association entre la détection de RV et les animaux en finition. L'acquisition de porcs en croissance de sources multiples était constamment associée avec une probabilité plus grande de détecter chaque virus.(Traduit par Docteur Serge Messier).

First detection and molecular characterization of Nebovirus in Brazil.

Nebovirus is a new genus of viruses belonging to the Caliciviridae family recently characterized in cattle, and is associated with gastrointestinal disorders, such as diarrhoea, anorexia and intestinal lesions particularly in calves. The aim of this study was to investigate the prevalence of neboviruses in Brazilian cattle and analyse phylogenetically the virus strains detected. A prevalence of 4·8% of neboviruses in faecal samples from 62 head of cattle from different Brazilian states was detected. All positive animals were aged 96·0% nt (100% aa) sequence identity between the virus sequences in this study and >88·8% nt (>94·4% aa) identity with Newbury1/UK. Our results indicate, for the first time, the occurrence of neboviruses in Brazil as well as in South America, and the first Newbury1-like nebovirus found outside the UK.

The impact of calicivirus mixed infection in an oyster-associated outbreak during a food festival.

BACKGROUND: Despite calicivirus food-borne outbreaks posing major public health concern worldwide, little information is at present available about the impact of caliciviruses mixed infection in an oyster-associated outbreak in China. OBJECTIVES: To investigate the clinical and epidemiologic characteristics of an oyster-associated calicivirus outbreak initiated by a food festival in Shanghai, China, in April 2014. STUDY DESIGN: Molecular epidemiological studies based on nucleotide sequencing and phylogenetic analysis of calicivirus strains from patients. RESULTS: A total of 65 of the 78 (83%) cases from this outbreak were associated with raw oyster consumption. Forty-six calicivirus strains were identified from 25 stool specimens with norovirus (NoV) GII.4 Sydney_2012, GII.13, GI.2, GI.5 and sapovirus (SaV) GI.2 being predominant genotypes and with a prevalence of triple-, double- and single-infection being 20%, 48% and 28%, respectively. Meanwhile, 13 putative NoV recombinants were indicated by the phylogenetic inconsistency between capsid and polymerase genotype, mainly including GII.Pe/GII.4 Sydney_2012. Molecular epidemiological investigation showed possible multiple route transmission in the field. The clinical and epidemiologic characteristics of the mixed point-source calicivirus outbreak also conformed to Kaplan's criteria. CONCLUSIONS: This is the first reported oyster-associated calicivirus outbreak with a high prevalence of mixed infection during a food festival described in China. Our investigation underscores the importance of early surveillance and comprehensive etiologic identification of mixed point-source outbreaks and the need for reliable standards of monitoring oysters to prevent and control calicivirus food-borne outbreaks in China.

Identification of a Bovine Enteric Calicivirus, Kirklareli Virus, Distantly Related to Neboviruses, in Calves with Enteritis in Turkey.

A calicivirus was detected in neonatal calves with enteritis in Kirklareli, Thrace, Turkey. In the full-length genome, Kirklareli virus was related (48% nucleotide identity) to bovine enteric caliciviruses (Nebovirus genus). The virus was also detected in a herd in Ankara, Central Anatolia, but not in other Turkish prefectures.