229 research outputs found
Les vecteurs viraux : outils modernes de vaccination
Les vaccins destinĂ©s aux animaux appartiennent Ă deux grandes catĂ©gories : les vaccins Ă agents vivants, et ceux Ă agents inertes. Depuis quelques annĂ©es, dans chacune de ces catĂ©gories, les innovations technologiques ont considĂ©rablement amĂ©liorĂ© et diversifiĂ© les stratĂ©gies vaccinales disponibles en fonction des contraintes liĂ©es Ă des prĂ©occupations tant dâinnocuitĂ©, que dâefficacitĂ© ou encore de nature Ă©conomique. Câest dans ce cadre que lâINRA a depuis de nombreuses annĂ©es orientĂ© les efforts de recherche vers lâĂ©laboration de nouveaux vaccins sâappuyant sur la mise au point de vecteurs viraux adaptĂ©s Ă diverses espĂšces animales et susceptibles de rĂ©pondre aux exigences des filiĂšres animales. Dans cette revue, nous dĂ©crivons ainsi les principes dâobtention et le dĂ©veloppement de vecteurs vaccinaux fondĂ©s sur lâemploi de poxvirus animaux Ă spectre dâhĂŽte Ă©troit (virus myxomateux), dâadenovirus humains ou animaux dĂ©fectifs (c'est-Ă -dire ayant perdu toute capacitĂ© Ă se multiplier chez lâhĂŽte) ainsi que de rhabdovirus de poissons modifiĂ©s par gĂ©nĂ©tique inverse. Des exemples dâapplication de vaccination non seulement contre des maladies animales dâintĂ©rĂȘt Ă©conomique, mais aussi dans le cadre de modĂšles de pathologie comparĂ©e permettent dâillustrer le potentiel indiscutable de ces vecteurs viraux et dâenvisager leur emploi pour le contrĂŽle de maladies animales Ă©mergentes ou rĂ©Ă©mergentes en Europe
Viromics on honey-baited FTA cards as a new tool for the detection of circulating viruses in mosquitoes
Worldwide, emerging and re-emerging infectious diseases (EIDs) are a major burden on public and animal health. Arthropod vectors, with mosquitoes being the main contributors of global disease, transmit more than 70% of the recognized EIDs. To assess new alternatives for arthropod-borne viral diseases surveillance, and for the detection of new viruses, honey-baited Flinders Technology Associates (FTA) cards were used as sugar bait in mosquito traps during entomological surveys at the Llobregat River Delta (Catalonia, Spain). Next generation sequencing (NGS) metagenomics analysis was applied on honey-baited FTA cards, which had been exposed to field-captured mosquitoes to characterize their associated virome. Arthropod- and plant-infecting viruses governed the virome profile on FTA cards. Twelve near-complete viral genomes were successfully obtained, suggesting good quality preservation of viral RNAs. Mosquito pools linked to the FTA cards were screened for the detection of mosquito-associated viruses by specific RT-PCRs to confirm the presence of these viruses. The circulation of viruses related to Alphamesonivirus, Quaranjavirus and unclassified Bunyavirales was detected in mosquitoes, and phylogenetic analyses revealed their similarities to viruses previously reported in other continents. To the best our knowledge, our findings constitute the first distribution record of these viruses in European mosquitoes and the first hint of insect-specific viruses in mosquitoesâ saliva in field conditions, demonstrating the feasibility of this approach to monitor the transmissible fraction of the mosquitoesâ virome. In conclusion, this pilot viromics study on honey-baited FTA cards was shown to be a valid approach for the detection of viruses circulating in mosquitoes, thereby setting up an alternative tool for arbovirus surveillance and control programs.info:eu-repo/semantics/publishedVersio
Hepatitis E : an emerging zoonosis ?
Hepatitis E virus (HEV) causes acute, enterically transmitted hepatitis. It is associated with epidemics
in endemic regions and sporadic cases in non-endemic regions. Although the waterborne origin of
epidemics is well documented, the origin of sporadic cases is frequently autochthonous and remains
unknown. Unlike the other hepatitis viruses, HEV has an animal reservoir. Phylogenetic studies on human
and animal strains, and the identification of cases transmitted directly from animal to man strongly
suggest that HEV is a zoonotic agent. It is essential to set up a surveillance system of the animal reservoir
and of human cases to determine the origin of all autochthonous cases. In addition, potential
routes of contaminations must be identified to define preventive measures.Le virus de l'hépatite E (VHE)
est responsable d'une hépatite aiguë à transmission entérique. La maladie existe sous formes
d'épidémies dans les régions endémiques (Asie, Afrique), et de cas sporadiques dans les
régions non endémiques. Alors que l'origine hydrique des épidémies est bien caractérisée,
celle des cas sporadiques est fréquemment autochtone et reste inconnue. Le VHE se
différencie des autres virus des hépatites par la présence d'un réservoir animal. Des études
phylogénétiques sur les souches humaines et animales, ainsi que l'identification de cas de
transmission directe de l'animal Ă l'homme suggĂšrent fortement que le VHE est un agent
zoonotique. Il faudrait mettre en place un systÚme de surveillance du réservoir animal,
couplé à un observatoire des cas humains, afin de déterminer l'origine de tous les cas
autochtones. Les voies possibles de contamination doivent Ă©galement ĂȘtre identifiĂ©es, afin
de définir des mesures de prévention
Comparison between Transcriptome Sequencing and 16S Metagenomics for Detection of Bacterial Pathogens in Wildlife
Background Rodents are major reservoirs of pathogens responsible for numerous zoonotic diseases in humans and livestock. Assessing their microbial diversity at both the individual and population level is crucial for monitoring endemic infections and revealing microbial association patterns within reservoirs. Recently, NGS approaches have been employed to characterize microbial communities of different ecosystems. Yet, their relative efficacy has not been assessed. Here, we compared two NGS approaches, RNA-Sequencing (RNA-Seq) and 16S-metagenomics, assessing their ability to survey neglected zoonotic bacteria in rodent populations.Methodology/Principal Findings : We first extracted nucleic acids from the spleens of 190 voles collected in France. RNA extracts were pooled, randomly retro-transcribed, then RNA-Seq was performed using HiSeq. Assembled bacterial sequences were assigned to the closest taxon registered in GenBank. DNA extracts were analyzed via a 16S-metagenomics approach using two sequencers: the 454 GS-FLX and the MiSeq. The V4 region of the gene coding for 16S rRNA was amplified for each sample using barcoded universal primers. Amplicons were multiplexed and processed on the distinct sequencers. The resulting datasets were de-multiplexed, and each read was processed through a pipeline to be taxonomically classified using the Ribosomal Database Project. Altogether, 45 pathogenic bacterial genera were detected. The bacteria identified by RNA-Seq were comparable to those detected by 16S-metagenomics approach processed with MiSeq (16S-MiSeq). In contrast, 21 of these pathogens went unnoticed when the 16S-metagenomics approach was processed via 454-pyrosequencing (16S-454). In addition, the 16S-metagenomics approaches revealed a high level of coinfection in bank voles. Conclusions/Significance :We concluded that RNA-Seq and 16S-MiSeq are equally sensitive in detecting bacteria. Although only the 16S-MiSeq method enabled identification of bacteria in each individual reservoir, with subsequent derivation of bacterial prevalence in host populations, and generation of intra-reservoir patterns of bacterial interactions. Lastly, the number of bacterial reads obtained with the 16S-MiSeq could be a good proxy for bacterial prevalence
Possible Zoonotic Transmission of Hepatitis E from Pet Pig to Its Owner
Hepatitis E is transmitted mainly by water or food, but in industrialized countries, all routes of transmission have not been identified. We describe possible zoonotic transmission of hepatitis E virus that involved direct contact between a pet pig and its owner
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