In France, an epidemic peak of acute diarrhea is observed each winter. Previous results suggested a viral etiology for these winter epidemics. We investigated the role of enteric viruses in acute diarrhea and their molecular diversity. One hundred sixty-one patients with acute diarrhea and 45 healthy patients (controls) from the general population were given a standardized questionnaire between December 1998 and May 1999. Stool specimens were screened for group A and C rotaviruses, human caliciviruses, astroviruses, and adenovirus types 40 and 41 by reverse transcription-PCR and/or enzyme immunoassay. Virologic analysis was positive for 63 cases (39%). Caliciviruses and group A rotaviruses were the most frequent (19 and 17% of cases, respectively). Two control stool specimens were found positive for group A rotavirus, and one was found positive for astrovirus. Molecular characterization of the strains disclosed a cocirculation of P[8],G1, P[8],G4, and P[4],G2 rotaviruses; type 1, 2, 3, 4, and 8 astroviruses; and Sapporo-like and Norwalk-like human caliciviruses. These four types of viruses accounted for an attributable risk of acute diarrhea of 34.7% for the general population, under the assumption of a causal role of these viruses.

We compiled sequence and epidemiological data from 172 caliciviruses detected in France from December 1998 to February 2004 in sporadic and outbreak cases. The results showed a cocirculation of strains with a majority of genogroup II (GII) noroviruses. Three groups of noroviruses, not detected before in our laboratory, emerged and spread during the period: the recombinant GGIIb and Norwalk-related strains not amplified in the polymerase gene in 2000 and a new Lordsdale variant in 2002. We observed that (i) GII-4 noroviruses were predominant in nursing home and hospital outbreaks but rare in oyster-and water-related outbreaks despite continuous circulation in the population; (ii) at the opposite, genogroup I strains were detected in the majority of environmental outbreaks; (iii) several strains were frequently found in oyster-and water-linked outbreaks (up to seven), whereas one single strain was detected when transmission was from person to person; and (iv) whereas GII noroviruses were predominant in sporadic cases where patients were under 15 years of age, GI strains were more frequent in outbreaks occurring in this age group. Finally, from a methodology point of view, this compilation shows that detection and characterization in the polymerase gene are not adequate in a significant number of cases and should be completed by amplification and sequencing in the capsid gene.

The Epstein-Barr virus (EBV) genome can persist in dividing human B cells as multicopy circular episomes. Viral episomes replicate in synchrony with host cell DNA and are maintained at a relatively constant copy number for a long time. Only two viral elements, the replication origin OriP and the EBNA-1 protein, are required for the persistence of viral genomes during latency. EBNA-1 activates OriP during the S phase and may also contribute to the partition and/or retention of viral genomes during mitosis. Indeed, EBNA-1 has been shown to interact with mitotic chromatin. Moreover, viral genomes are noncovalently associated with metaphase chromosomes. This suggests that EBNA-1 may facilitate the anchorage of viral genomes on cellular chromosomes, thus ensuring proper partition and retention. In the present paper, we have investigated the chromosome-binding activity of EBV EBNA-1, herpesvirus papio (HVP) EBNA-1, and various derivatives of EBV EBNA-1, fused to a variant of the green fluorescent protein. The results show that binding to metaphase chromosomes is a common property of EBV and HVP EBNA-1. Further studies indicated that at least three independent domains (CBS-1, -2, and -3) mediate EBNA-1 binding to metaphase chromosomes. In agreement with the anchorage model, two of these domains mapped to a region that has been previously demonstrated to be required for the long-term persistence of OriP-containing plasmids.

Background Gastrointestinal symptoms are not an uncommon manifestation of an influenza virus infection. In the present study, we aimed to investigate the presence of influenza viruses in the stools of adult patients consulting their general practitioner for uncomplicated acute diarrhea (AD) and the proportion of concurrent infections by enteric and influenza viruses. Method A case-control study was conducted from December 2010 to April 2011. Stool specimens were collected and tested for influenza viruses A (seasonal A/H3N2 and pandemic A/H1N1) and B, and for four enteric viruses (astrovirus, group A rotavirus, human enteric adenovirus, norovirus of genogroups I – NoVGI - and genogroup II - NoVGII). Results General practitioners enrolled 138 cases and 93 controls. Of the 138 stool specimens collected, 92 (66.7%) were positive for at least one of the four enteric viruses analysed and 10 (7.2%) tested positive for one influenza virus. None of these 10 influenza positive patients reported respiratory symptoms. In five influenza-positive patients (3.6%), we also detected one enteric virus, with 4 of them being positive for influenza B (2 had co-detection with NoVGI, 1 with NoVGII, and 1 with astrovirus). None of the 93 controls tested positive for one of the enteric and/or other influenza viruses we investigated. Conclusions In this study we showed that the simultaneous detection of influenza and enteric viruses is not a rare event. We have also reported, for the first time in general practice, the presence of seasonal and pandemic influenza viruses in the stools of adult patients consulting for uncomplicated AD. A simultaneous investigation of enteric and influenza viruses in patients complaining of gastrointestinal symptoms could be useful for future studies to better identify the agents responsible for AD.