The viral susceptibility of the <i>Haloferax</i> species

Viruses can infect members of all three domains of life. However, little is known about viruses infecting archaea and the mechanisms that determine their host interactions are poorly understood. Investigations of molecular mechanisms of viral infection rely on genetically accessible virus–host model systems. Euryarchaea belonging to the genus Haloferax are interesting models, as a reliable genetic system and versatile microscopy methods are available. However, only one virus infecting the Haloferax species is currently available. In this study, we tested ~100 haloarchaeal virus isolates for their infectivity on 14 Haloferax strains. From this, we identified 10 virus isolates in total capable of infecting Haloferax strains, which represented myovirus or siphovirus morphotypes. Surprisingly, the only susceptible strain of all 14 tested was Haloferax gibbonsii LR2-5, which serves as an auspicious host for all of these 10 viruses. By applying comparative genomics, we shed light on factors determining the host range of haloarchaeal viruses on Haloferax. We anticipate our study to be a starting point in the study of haloarchaeal virus–host interaction

Chikungunya intra-vector dynamics in Aedes albopictus from Lyon (France) upon exposure to a human viremia-like dose range reveals vector barrier’s permissiveness and supports local epidemic potential

Arbovirus emergence and epidemic potential, as approximated by the vectorial capacity formula, depends on host and vector parameters, including the vector’s intrinsic ability to replicate then transmit the pathogen known as vector competence. Vector competence is a complex, time-dependent,quantitative phenotype influenced by biotic and abiotic factors. A combination of experimental andmodelling approaches is required to assess arbovirus intra-vector dynamics and estimate epidemicpotential. In this study, we measured infection, dissemination, and transmission dynamics of chikungunya virus (CHIKV) in a field-derived Aedes albopictus population (Lyon, France) after oral exposureto a range of virus doses spanning human viraemia. Statistical modelling indicates rapid and efficientCHIKV progression in the vector mainly due to an absence of a dissemination barrier, with 100% ofthe infected mosquitoes ultimately exhibiting a disseminated infection, regardless of the virus dose.Transmission rate data revealed a time-dependent, but overall weak, transmission barrier, with individuals transmitting as soon as 2 days post-exposure (dpe) and &gt;50% infectious mosquitoes at 6dpe for the highest dose. Based on these experimental intra-vector dynamics data, epidemiologicalsimulations conducted with an agent-based model showed that even at low mosquito biting rates,CHIKV could trigger outbreaks locally. Together, this reveals the epidemic potential of CHIKV upontransmission by Aedes albopictus in mainland Franc

La Transmission verticale des arbovirus chez les moustiques vecteurs (revue systématique)

TOURS-BU Sciences Pharmacie (372612104) / SudocSudocFranceF

Statistical modeling of chikungunya virus intra-vector infection dynamics in a French Aedes albopictus population reveals an explosive epidemic potential

Abstract Arbovirus emergence and epidemic potential, as approximated by the vectorial capacity formula, depends on several host and vector parameters including vector intrinsic ability to transmit the pathogen. Such ability, called vector competence is influenced by biotic ( e.g . virus and vector genotype) and abiotic ( e.g . temperature). Vector competence is often evaluated as a qualitative phenotype although it is a multistep, time-dependent, quantitative phenotype. Combination of experimental and modelling approaches can i) capture intra-vector dynamics of arboviral infection and ii) use data to estimate arbovirus epidemic potential. Here, we measured individual Aedes albopictus (Lyon, France) mosquitoes infection, dissemination, and transmission rate upon oral exposure to chikungunya virus (CHIKV, La Reunion Island isolate) at eleven time-points from day 2 to day 20 post-exposure (dpe) for a range of CHIKV infectious doses spanning human viremia. Statistical modelisation indicates an explosive CHIKV intra-vector dynamics mainly due to an absence of dissemination barrier with 100% of the infected mosquitoes ultimately exhibiting a disseminated infection regardless of the viral dose. Transmission rate data revealed a time and dose-dependent but overall weak transmission barrier with individuals transmitting as soon as 2 dpe and >50% infectious mosquitoes at 6 dpe for the highest dose. Epidemiological simulations conducted with an Agent-Based Model based on experimental intra-vector dynamics data showed that even at low mosquito biting rates, CHIKV triggers explosive outbreaks. Together, this reveals the high epidemic potential of this CHIKV isolate with this French metropolitan population of Aedes albopictus

Chikungunya intra-vector dynamics in Aedes albopictus from Lyon (France) upon exposure to a human viremia-like dose range reveals vector barrier’s permissiveness and supports local epidemic potential

International audienceArbovirus emergence and epidemic potential, as approximated by the vectorial capacity formula, depends on host and vector parameters, including the vector’s intrinsic ability to replicate then transmit the pathogen known as vector competence. Vector competence is a complex, time dependent, quantitative phenotype influenced by biotic and abiotic factors. A combination of experimental and modelling approaches is required to assess arbovirus intra-vector dynamics and estimate epidemic potential. In this study, we measured infection, dissemination, and transmission dynamics of chikungunya virus (CHIKV) in a field-derived Aedes albopictus population (Lyon, France) after oral exposure to a range of virus doses spanning human viraemia. Statistical modelling indicates rapid and efficient CHIKV progression in the vector mainly due to an absence of a dissemination barrier, with 100% of the infected mosquitoes ultimately exhibiting a disseminated infection, regardless of the virus dose. Transmission rate data revealed a time-dependent, but overall weak, transmission barrier, with individuals transmitting as soon as 2 days post-exposure (dpe) and =50% infectious mosquitoes at 6 dpe for the highest dose. Based on these experimental intra-vector dynamics data, epidemiological simulations conducted with an agent-based model showed that even at low mosquito biting rates, CHIKV could trigger outbreaks locally. Together, this reveals the epidemic potential of CHIKV upon transmission by Aedes albopictus in mainland France