Dynamiques des agricultures biologiques. Effets de contexte et appropriations

Ancré dans différentes disciplines des sciences sociales (anthropologie, sociologie, géographie, sciences de l’éducation), cet ouvrage analyse les nombreuses formes d’agricultures alternatives au modèle agricole dit conventionnel. Organisé en trois parties (les dynamiques de construction des courants et organisations, les trajectoires d’agriculteurs et les relations tissées avec les non agriculteurs), il étudie les facteurs d’influence qui expliquent les pratiques observées, et interroge non seulement la relation complexe qu’entretiennent ces alternatives avec « leurs » configurations, mais aussi les dimensions méthodologiques propres aux approches disciplinaire

Role of pathogens in life-threatening encephalitides analyzed by untargeted transcriptomic analysis of pathological brain tissues

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The virome of Rhipicephalus, Dermacentor and Haemaphysalis ticks from Eastern Romania includes novel viruses with potential relevance for public health

International audienceTicks are the second arthropod vectors, after mosquitoes, responsible for the spread of viruses and bacteria from wildlife to domestic animals and humans (Labuda & Nuttall, 2004). The ability of ticks to transmit a wide range of microbial pathogens, combined with their promiscuous feeding and geographical range expansion, makes them a substantial threat to animal and human health (Jongejan & Uilenberg, 2004). Viral disease-causing vectors are found mostly in the following tick families: Ixodes, Haemaphysalis, Hyalomma, Amblyomma, Dermacentor, Rhipicephalus and Boophilus (Labuda & Nuttall, 2004). The tick microbiome consists of communities of viruses, bacteria and eukaryotes (Havlikova et al., 2013), among which several pathogens coexist within the commensal flora. Such pathogens of medical importance include Crimean-Congo haemorrhagic fever virus (CCHFV) (Bente et al., 2013), Kyasanu

A Search for Tick-Associated, Bronnoya-like Virus Spillover into Sheep

Tick-borne diseases are responsible for many vector-borne diseases within Europe. Recently, novel viruses belonging to a new viral family of the order Bunyavirales were discovered in numerous tick species. In this study, we used metatranscriptomics to detect the virome, including novel viruses, associated with Ixodes ricinus collected from Romania and France. A bunyavirus-like virus related to the Bronnoya virus was identified for the first time in these regions. It presents a high level of amino-acid conservation with Bronnoya-related viruses identified in I. ricinus ticks from Norway and Croatia and with the Ixodes scapularis bunyavirus isolated from a tick cell line in Japan in 2014. Phylogenetic analyses revealed that the Bronnoya viruses’ sub-clade is distinct from several Bunyavirales families, suggesting that it could constitute a novel family within the order. To determine if Bronnoya viruses could constitute novel tick-borne arboviruses, a Luciferase immunoprecipitation assay for detecting antibodies in the viral glycoprotein of the Romanian Bronnoya virus was used to screen sera from small ruminants exposed to tick bites. No positive serum was detected, suggesting that this virus is probably not able to infect small ruminants. This study represents the first serological investigation of mammalian infections with a Bronnoya-like virus and an initial step in the identification of potential new emergences of tick-borne arboviruses

Progressive multifocal leukoencephalopathy and oligodendroglioma in a monkey co-infected by simian immunodeficiency virus and simian virus 40

A rhesus monkey experimentally inoculated with simian immunodeficiency virus (SIV) mac251 was killed 42 months later because of poor general condition. CD4 lymphocyte count which was 3,430/mm3 before inoculation, had decreased to 638/mm3 2 months before death. Neuropathological examination revealed changes characteristic of progressive multifocal leukoencephalopathy (PML) in the white matter of the cerebral hemispheres and brain stem. In situ hybridization was negative for JC virus but markedly positive for simian virus 40 (SV40) in the nuclei of many oligodendrocytes. Many oligodendrocytes also expressed p53. Within an area involved by PML, there was a densely cellular tumor with honeycomb appearance and elongated vessels characteristic of oligodendrogliomas. Within the tumor in situ hybridization for SV40 and immunocytochemistry for p53 were negative. Opportunistic infection by SV40 has been occasionally reported in experimentally SIV-infected monkeys resulting in PML or malignant astrocytoma. Association of JC virus-induced PML and astrocytomas has been reported in three human cases without AIDS. In those cases, as in our monkey, polyomaviruses (SV40 or JC virus) were expressed in the areas with PML but not in the glial tumor. Association of PML and oligodendroglioma has not been reported previously to our knowledge. The relationship between oligodendrocyte proliferation and polyomavirus infection of oligodendrocytes is unclear. Our findings suggest that binding of the viral protein to p53 may result in inactivation of the pro-apoptotic protein favoring the proliferation of a randomly occurring tumoral clone of oligodendrocytes.</p

Detection of Phenuiviridae, Chuviridae Members, and a Novel Quaranjavirus in Hard Ticks From Danube Delta

International audienceTicks are involved in the transmission of various pathogens and several tick-borne diseases cause significant problems for the health of humans and livestock. The members of the Quaranjavirus genus are mainly associated with argas ticks but recent studies demonstrated the presence of novel quaranjaviruses-like in ixodid ticks. In 2020, 169 Rhipicephalus sanguineus ticks were collected in Southern Romania from small ruminants and analyzed by high-throughput transcriptome sequencing. Among the viral families that infect Romanian ticks, we have identified sequences from Phenuiviridae (Brown dog tick phlebovirus 1 [BDTPV1] and Brown dog tick phlebovirus 2 [BDTPV2]) and Chuviridae families (Cataloi mivirus [CTMV]), and numerous sequences from a new quaranjavirus-like, tentatively named Cataloi tick quaranjavirus (CTQV). Phylogenetic analyses performed on the five segments show that CTQV is phylogenetically positioned within a clade that encompasses Ixodidae -borne viruses associated with iguanas, small ruminants, seabirds, and penguins distributed across different geographical areas. Furthermore, CTQV is positioned differently depending on the segment considered. This is the first report on the detection of a quaranjavirus-like in Eastern Europe. Further investigations are needed to discern its infectivity and pathogenicity against vertebrates

Broad range molecular detection methods identify only Borrelia spp. in erythema migrans biopsies and blood of tick-bitten patients

We thank the Biomics platform of Institut Pasteur for providing access to the sequencers.International audienceIn this multicenter study conducted in France, we challenged the hypothesis of the transmission of pathogens other than Borrelia spp. in 22 patients developing erythema migrans following a tick bite. Using a combination of high-throughput microfluidic PCRs and agnostic metagenomics on skin biopsies and blood samples, no microorganisms other than Borrelia spp. was found

Synthesis of phosphoantigens: scalable accesses to enantiomers of BrHPP and studies on N-HDMAPP synthesis

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