Evidence for human norovirus infection of dogs in the United kingdom.

Human noroviruses (HuNoVs) are a major cause of viral gastroenteritis, with an estimated 3 million cases per year in the United Kingdom. HuNoVs have recently been isolated from pet dogs in Europe (M. Summa, C.-H. von Bonsdorff, and L. Maunula, J Clin Virol 53:244-247, 2012, http://dx.doi.org/10.1016/j.jcv.2011.12.014), raising concerns about potential zoonotic infections. With 31% of United Kingdom households owning a dog, this could prove to be an important transmission route. To examine this risk, canine tissues were studied for their ability to bind to HuNoV in vitro. In addition, canine stool samples were analyzed for the presence of viral nucleic acid, and canine serum samples were tested for the presence of anti-HuNoV antibodies. The results showed that seven different genotypes of HuNoV virus-like particles (VLPs) can bind to canine gastrointestinal tissue, suggesting that infection is at least theoretically possible. Although HuNoV RNA was not identified in stool samples from 248 dogs, serological evidence of previous exposure to HuNoV was obtained in 43/325 canine serum samples. Remarkably, canine seroprevalence for different HuNoV genotypes mirrored the seroprevalence in the human population. Though entry and replication within cells have not been demonstrated, the canine serological data indicate that dogs produce an immune response to HuNoV, implying productive infection. In conclusion, this study reveals zoonotic implications for HuNoV, and to elucidate the significance of this finding, further epidemiological and molecular investigations will be essential.This collaborative project was facilitated by the Society of Microbiology's President's Fund awarded to S.L.C. and by the Region des Pays de la Loire ARMINA project. This work was supported by a Ph.D. studentship from the Medical Research Council to S.L.C. and a Wellcome Trust Senior Fellowship to I.G. (WT097997MA). I.G. is a Wellcome Senior Fellow.This is the final published version of the article. It was originally published in the Journal of Clinical Microbiology (Caddy S, et al., Journal of Clinical Microbiology, 2015, 53, 1873-1883, doi:10.1128/JCM.02778-14). The final version is available at http://dx.doi.org/10.1128/JCM.02778-1

Demographic characteristic and detected enteric viruses in patients with cosavirus, salivirus or bufavirus infections.

<p>Demographic characteristic and detected enteric viruses in patients with cosavirus, salivirus or bufavirus infections.</p

Adhesion of human pathogenic enteric viruses and surrogate viruses to inert and vegetal food surfaces

International audienceEnteric viruses, particularly human Noroviruses (NoV) and hepatitis A virus (HAV), are key food-borne pathogens. The attachment of these pathogens to foodstuff and food-contact surfaces is an important mechanism in the human contamination process. Studies were done to investigate the nature of the physicochemical forces, such as hydrophobic and electrostatic ones, involved in the interaction virus/matrix but, at this day, only few data are available concerning surface properties of viruses and prediction of the adhesion capacity of one specific virus onto matrices is still very difficult.The purpose of this study was to propose a reference system, including a representative virus surrogate, able to predict as close as possible behaviour of pathogenic viruses in term of adhesion on inert (stainless steel and polypropylene) and food surfaces (lettuce leaves, strawberries and raspberries). The adhesion of human pathogenic enteric viruses, cultivable strain of HAV and non-cultivable strains of human NoV (genogroups I and II), have been quantified and compared to these of human enteric viruses surrogates, included the MNV-1 and three F-specific RNA bacteriophages (MS2, GA and Qβ). A standardized approach was developed to assess and quantify viral adhesion on tested matrices after a contact time with each virus using real-time RT-PCR. Methods used for virus recovery were in accordance with the CEN recommendations, including a bovine Enterovirus type 1 as control to monitor the efficiency of the extraction process and amplification procedure from directly extracted or eluted samples. The adhesion of human pathogenic viruses, ranging from 0.1 to 2%, could be comparable for all matrices studied, except for NoV GII on soft fruits. Adhesion percentages obtained for the studied surrogate virus and phages were shown to be comparable to those of HAV and NoV on inert and lettuce surfaces. The MNV-1 appeared as the best candidate to simulate adhesion phenomena of all human pathogenic enteric viruses on all studied surfaces, while MS2 and GA bacteriophages could be a good alternative as model of viral adhesion on inert and lettuce surfaces. These results will be usable to design relevant experimental systems integrating adhesion behaviour of enteric viruses in the assessment of the efficiency of a technological or hygienic industrial process.Highlights-A method was developed for the assessment of viral adhesion from different surfaces.- The adhesion of human pathogenic enteric viruses and surrogate viruses was compared. -The adhesion of HAV and Norovirus ranged from 0.1 to 2% on inert and vegetal matrices. - MNV-1 appeared as the best candidate to simulate adhesion phenomena of human viruses. - Bacteriophages could be a good model of viral adhesion on inert and lettuce surface

Phylogenetic trees of saliviruses detected in diarrheal Tunisian children.

<p><b>A.</b> VP0 region of salivirus (815 nt); <b>B.</b> 2CHel region of salivirus (275 nt); <b>C.</b> 3Dpol region of (686 nt); Phylogenetic trees were inferred using the Maximum Likelihood method based on the Tamura-3-parameter nucleotide substitution model with a discrete gamma distribution. Bootstraps values were calculated from 1000 replicates. Strains of this study are shown in blue. Genotypes are shown in bold.</p

Epidemiological Impact of GII.17 Human Noroviruses Associated With Attachment to Enterocytes

International audienceFor the last 30 years, molecular surveys have shown that human norovirus (HuNoV), predominantly the GII.4 genotype, is one of the main causative agents of gastroenteritis. However, epidemiological surveys have revealed the worldwide emergence of GII.17 HuNoVs. Genetic analysis confirmed that GII.17 strains are distributed into three variants (i.e., Kawasaki 308, Kawasaki 323, and CS-E1). Here, virus-like particles (VLPs) were baculovirus-expressed from these variants to study putative interactions with HBGA. Qualitative analysis of the HBGA binding profile of each variant showed that the most recent and predominant GII.17 variant, Kawasaki 308, possesses a larger binding spectrum. The retrospective study of GII.17 strains documented before the emergence of the dominant Kawasaki 308 variant showed that the emergence of a new GII.17 variant could be related to an increased binding capacity toward HBGA. The use of duodenal histological sections confirmed that recognition of enterocytes involved HBGA for the three GII.17 variants. Finally, we observed that the relative affinity of recent GII.17 VLPs for HBGA remains lower than that of the GII.4-2012 variant. These observations suggest a model whereby a combination of virological factors, such as polymerase fidelity and increased affinity for HBGA, and immunological factors was responsible for the incomplete and non-persistent replacement of GII.4 by new GII.17 variants

Oligonucleotides used for detection and genotyping of cosavirus, salivirus and bufavirus in this study.

<p>Oligonucleotides used for detection and genotyping of cosavirus, salivirus and bufavirus in this study.</p

Phylogenetic trees of cosaviruses detected in diarrheal Tunisian children.

<p><b>A.</b> VP1 region of cosavirus (904 nt); <b>B.</b> 3Dpol region of cosavirus (400 nt). Phylogenetic trees were inferred using the Maximum Likelihood method based on the Tamura-3-parameter nucleotide substitution model with a discrete gamma distribution. Bootstraps values were calculated from 1000 replicates. Strains of this study are shown in red. Genotypes are shown in bold.</p

Phylogenetic trees of bufaviruses detected in diarrheal Tunisian children.

<p><b>A.</b> VP2 region of bufavirus (1710 nt); <b>B.</b> NS1 region of bufavirus (441 nt) Phylogenetic trees were inferred using the Maximum Likelihood method based on the Tamura-3-parameter nucleotide substitution model with a discrete gamma distribution. Bootstraps values were calculated from 1000 replicates. Strains of this study are shown in green. Genotypes are shown in bold.</p