Éditeur(s) : Elsevier
Résumé : To improve the knowledge of the survival of enteric viruses in a marine environment, the influence of physico-chemical parameters (temperature, UV, salinity) on the survival of infectious poliovirus 1 and hepatitis A Virus (HAV) in seawater was first studied, the influence of suspended solids (SS) on poliovirus adsorption and survival in seawater was then evaluated and the detection of rotavirus genome in environmental samples (shellfish, river water, treated wastewater) was finally investigated. The results show that temperature has a major impact on virus survival in seawater as the time necessary to inactivate 90 % of the virus (T-90) is 671 days at 4 degrees C and only 25 days at 25 degrees C. Ultraviolet light (42 mW s cm(-2)) rapidly inactivates viruses but HAV is more resistant (T-90 = 2.6 min) than the poliovirus 1 (T-90 = 1.3 min). By contrast, seawater salinity has no effect on virus survival. In presence of SS, 90 % to 99.9 % of the viruses were adsorbed. This adsorption does not provide any protection for viruses with low SS concentrations (3 and 15 mg L-1) but a slight increase in virus survival was observed with a high SS concentration (500 mg L-1). Finally environmental sample analysis indicated that 20 % shellfish, about 40 % river water and 40 % treated wastewater tested positive for the rotavirus genome.
Ce travail a pour but de mieux comprendre le devenir des virus en milieu marin. Dans ce cadre, l'influence de certains paramètres physicochimiques (température, UV et salinité) sur le pouvoir infectieux du poliovirus 1 et du virus de l'hépatite A (VHA) en eau de mer a été évalué, puis l'adsorption du poliovirus 1 sur les matières en suspension (MES) a été étudié, ainsi que les conséquences sur le pouvoir infectieux du virus et enfin le génome des rotavirus a été recherché en milieu naturel (eaux et coquillages). Les résultats montrent que la température est un paramètre important pour la survie des virus puisque le temps nécessaire à inactiver 90 % des virus (T90) en eau de mer est de 671 j à 4 °C alors qu'il est seulement de 25 j à 25 °C. Le rayonnement ultraviolet (42 mW s cm−2) testé en pilote expérimental, permet d'obtenir une inactivation rapide du poliovirus 1 (T90 = 1,3 min). Le VHA est plus résistant avec un T90 = 2,6 min. En revanche la salinité de l'eau de mer n'a pas d'influence sur la survie des virus. En ce qui concerne l'influence des MES, les résultats montrent qu'en présence de 3, 15 et 500 mg L−1 de Na-montmorillonite la majorité des virus est adsorbée (90 à 99,9 %). Cet état adsorbé ne procure aucune protection aux virus pour les faibles concentrations de MES (3 et 15 mg L−1) alors qu'une augmentation significative de survie est observée pour les fortes concentrations (500 mg L−1). Enfin, l'analyse d'échantillon de l'environnement a montré que 20 % des fruits de mer, environ 40 % des eaux de rivière et environ 40 % des eaux usées traitées testées contenaient du génome de rotavirus.
Oceanologica Acta (0399-1784) (Elsevier), 1998-11 , Vol. 21 , N. 6 , P. 983-992

Droits : 1998 Ifremer / CNRS / IRD - Published by Elsevier SAS
http://archimer.ifremer.fr/doc/1998/publication-846.pdf
DOI:10.1016/S0399-1784(99)80020-6
http://archimer.ifremer.fr/doc/00000/846/

Éditeur(s) : HAL CCSD Wiley-Blackwell
Résumé : International audience
AIMS: Virus detection has often been difficult due to a low concentration in water. In this study, we developed a new procedure based on concentration of virus particles on an innovative support: poly-L-lysine dendrigrafts (DGL), coupled with directed nucleic acid extraction and real-time PCR quantification. METHODS AND RESULTS: This method was evaluated using the bacteriophage MS2 as a model virus. This virus exhibited the size and structural properties of human pathogenic enteric viruses and has often been used to assess new supports of concentration. Moreover, this bacteriophage is also a faecal contamination indicator. In this study, many water filtration conditions were tested (volume of water, concentration, etc.), and more than 80% of bacteriophage were recovered after filtration on polymer, in most conditions. We demonstrated that the method was linear (slope = 0*99 ± 0*04 and Y intercept when x = -0*02 ± 0*28), valid (as manipulators, tested concentrations, volumes of sample and batch of polymer did not have any influence on concentration) and sensitive (allowing to concentrate up to 16,600-fold 1 l of sample and to detect and quantify down to 750 GC l(-1) and 7500 GC l(-1), respectively). CONCLUSIONS: To conclude, this support exhibits high interest to retain viruses and to allow to detect low concentration of virus in water. SIGNIFICANCE AND IMPACT OF THE STUDY: This study gives valuable advance in the methods of concentration and diagnosis of virus in water.
Journal of Applied Microbiology

hal-00828987
https://hal.archives-ouvertes.fr/hal-00828987
DOI : 10.1111/jam.12209
PUBMED : 23551794

Éditeur(s) : HAL CCSD Wiley-Blackwell
Résumé : International audience
Virus detection has often been difficult due to a low concentration in water. In this study, we developed a new procedure based on concentration of virus particles on an innovative support: poly-L-lysine dendrigrafts (DGL), coupled with directed nucleic acid extraction and real-time PCR quantification. Methods and Results: This method was evaluated using the bacteriophage MS2 as a model virus. This virus exhibited the size and structural properties of human pathogenic enteric viruses and has often been used to assess new supports of concentration. Moreover, this bacteriophage is also a faecal contamination indicator. In this study, many water filtration conditions were tested (volume of water, concentration, etc.), and more than 80% of bacteriophage were recovered after filtration on polymer, in most conditions. We demonstrated that the method was linear (slope = 0 99 0 04 and Y intercept when x = 0 02 0 28), valid (as manipulators, tested concentrations, volumes of sample and batch of polymer did not have any influence on concentration) and sensitive (allowing to concentrate up to 16 600-fold 1 l of sample and to detect and quantify down to 750 GC l 1 and 7500 GC l 1, respectively). Conclusions: To conclude, this support exhibits high interest to retain viruses and to allow to detect low concentration of virus in water. Significance and Impact of the Study: This study gives valuable advance in the methods of concentration and diagnosis of virus in water.
Journal of Applied Microbiology

hal-00932328
https://hal.archives-ouvertes.fr/hal-00932328
DOI : 10.1111/jam.12209

Éditeur(s) : HAL CCSD American Society for Microbiology
Résumé : International audience
Coronaviruses (CoVs) have shown neuroinvasive properties in human and animal secondary to replication in peripheral organ but the mechanism of neuroinvasion is unknown. The major aim of our work was to evaluate the ability of CoVs to enter the central nervous system (CNS) through the blood brain barrier (BBB). Using the high hepatotropic mouse hepatitis virus (MHV) type 3, its attenuated variant 51.6-MHV3, showing low tropism for endothelial cells, and the low hepatotropic MHV-A59 strains from murine coronavirus group, we investigated the viral-induced dysfunctions of BBB in vivo and in brain microvascular endothelial cells (BMECs) in vitro. We report here a MHV strain-specific ability to cross the BBB during acute infection according to their virulence for liver. Brain invasion was only observed in MHV3-infected mice and correlated with enhanced BBB permeability associated with decreased expression of ZO-1, VE-cadherin and occludin but not claudin-5 in the brain or in cultured BMECs. BBB breakdown in MHV3 infection was not related to production of barrier-dysregulating inflammatory cytokines or chemokines by infected BMECs but rather to a downregulation of barrier protective IFN-β production. Our findings highlight the importance of IFN-β production by infected BMECs in preserving BBB function and preventing access of blood-borne infectious viruses to the brain. IMPORTANCE: Coronaviruses (CoVs) infect several mammals including humans and are associated with respiratory, gastrointestinal and/or neurological diseases. Some evidences suggest that human respiratory CoVs may show neuroinvasive properties. Indeed, the SARS-CoV, causing severe acute respiratory syndrome, and the CoVs OC43 and 229E were found in the brains of SARS and multiple sclerosis patients respectively. These finding suggest that hematogenous spread CoVs may gain access to CNS at the BBB level. Herein we report for the first time that CoVs exhibit ability to cross the BBB according to strain virulence. BBB invasion by CoVs correlates with viral-induced disruption of tight junctions on BMECs, leading to BBB dysfunction and enhanced permeability. We provide evidence that production of IFN-β by BMECs during CoV infection may prevent BBB breakdown and brain viral invasion
ISSN: 0022-538X

hal-01187308
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01187308
DOI : 10.1128/JVI.01501-15
PUBMED : 26202229