The Experts below are selected from a list of 309 Experts worldwide ranked by ideXlab platform

Stéphane Priet - One of the best experts on this subject based on the ideXlab platform.

  • New reverse genetics and transfection methods to rescue Arboviruses in mosquito cells
    Scientific Reports, 2017
    Co-Authors: Thérèse Atieh, Antoine Nougairède, Raphaëlle Klitting, Fabien Aubry, Anna-bella Failloux, Xavier De Lamballerie, Stéphane Priet
    Abstract:

    Reverse genetics is a critical tool to decrypt the biological properties of Arboviruses. However, whilst reverse genetics methods have been usually applied to vertebrate cells, their use in insect cells remains uncommon due to the conjunction of laborious molecular biology techniques and of specific difficulties surrounding the transfection of such cells. To leverage reverse genetics studies in both vertebrate and mosquito cells, we designed an improved DNA transfection protocol for insect cells and then demonstrated that the simple and flexible ISA (Infectious Subgenomic Amplicons) reverse-genetics method can be efficiently applied to both mammalian and mosquito cells to generate in days recombinant infectious positive-stranded RNA viruses belonging to genera Flavivirus (Japanese encephalitis, Yellow fever, West Nile and Zika viruses) and Alphavirus (Chikungunya virus). This method represents an effective option to potentially overcome technological issues related to the study of Arboviruses. Arboviruses (Arthropod-borne viruses) constitute a large group of viruses carried and spread by blood feeding arthropods, especially mosquitoes, ticks and sandflies. They can be transmitted to a variety of vertebrates and are responsible for significant morbidity and mortality amongst humans and farmed animals globally. Arboviral diseases in humans range from mild febrile illness to severe encephalitis or haemorrhagic fever 1. Iterative outbreaks worldwide over the past decades have highlighted the emergence or re-emergence potential of Arboviruses, which are thus considered to be significant public and animal health threats 1–3. Most Arboviruses of public health importance are single-stranded RNA viruses belonging to the families Flavi-, Toga-, or Bunyaviridae. Research focusing on Arboviruses knew dramatic progress thanks to the use of reverse genetics systems allowing the study of virus life cycles, understanding the effect of specific mutations on viral replication or pathogen-esis, and designing new vaccine strategies 4,5. However, these reverse genetics systems focused to date almost exclusively on mammalian cells. Since Arboviruses life cycle involves replication in both invertebrate vectors and vertebrate hosts, a simple and universal reverse genetics method allowing producing recombinant Arboviruses in both vertebrate and arthropod cells would obviously facilitate the study of arbovirus biological properties, of their genomic evolution or cell interactions and restrictions. This awaited knowledge could provide in the future the key elements needed to predict outbreaks and to find efficient therapy. Unfortunately, although most reverse genetics systems proved to be efficient to recover Arboviruses from vertebrate cell lines (for reviews see 4,5), very few studies have reported such systems for arthropod cells and especially for cells from Aedes mosquitoes , one of the most important arbovirus vectors globally 6. Indeed, reverse genetics systems designed for positive-sense single-stranded RNA viruses in Aedes mosquito cells are typically based to date on the lipofection or electroporation of synthetic capped RNA transcripts generated by in vitro transcription from SP6-7–9 or T7 promoter-driven 10–16 full-length viral cDNA constructs. A second system only used marginally and based on the direct transfection of a T7 promoter-driven infectious clone in an Aedes mosquito cell line stably expressing the T7 RNA polymerase was established to produce a minireplicon of the Bunyamwera negative-strand RNA virus 17. Nevertheless, these reverse genetics systems suffer from two main limitations. First, the construction of full-length viral cDNA clones remains difficult and time consuming. To circumvent this issue, we recently developed a novel bacterium-free method of reverse genetics called ISA (Infectious Subgenomic Amplicons) 18. The

Ernest A Gould - One of the best experts on this subject based on the ideXlab platform.

  • Emerging Arboviruses: Why today?
    One health (Amsterdam Netherlands), 2017
    Co-Authors: Ernest A Gould, Stephen Higgs, John H.-o. Pettersson, Rémi N. Charrel, Xavier De Lamballerie
    Abstract:

    The recent global (re)emergence of arthropod-borne viruses (Arboviruses), such as chikungunya and Zika virus, was widely reported in the media as though it was a new phenomenon. This is not the case. Arboviruses and other human microbial pathogens have been (re)emerging for centuries. The major difference today is that arbovirus emergence and dispersion are more rapid and geographically extensive, largely due to intensive growth of global transportation systems, arthropod adaptation to increasing urbanisation, our failure to contain mosquito population density increases and land perturbation. Here we select examples of (re)emerging pathogenic Arboviruses and explain the reasons for their emergence and different patterns of dispersal, focusing particularly on the mosquito vectors which are important determinants of arbovirus emergence. We also attempt to identify Arboviruses likely to (re)emerge in the future.

  • Factors responsible for the emergence of Arboviruses; strategies, challenges and limitations for their control
    Emerging microbes & infections, 2015
    Co-Authors: Guodong Liang, Xiaoyan Gao, Ernest A Gould
    Abstract:

    Slave trading of Africans to the Americas, during the 16th to the 19th century was responsible for the first recorded emergence in the New World of two arthropod-borne viruses (Arboviruses), yellow fever virus and dengue virus. Many other Arboviruses have since emerged from their sylvatic reservoirs and dispersed globally due to evolving factors that include anthropological behaviour, commercial transportation and land-remediation. Here, we outline some characteristics of these highly divergent Arboviruses, including the variety of life cycles they have developed and the mechanisms by which they have adapted to evolving changes in habitat and host availability. We cite recent examples of virus emergence that exemplify how Arboviruses have exploited the consequences of the modern human lifestyle. Using our current understanding of these viruses, we also attempt to demonstrate some of the limitations encountered in developing control strategies to reduce the impact of future emerging arbovirus diseases. Finally, we present recommendations for development by an international panel of experts reporting directly to World Health Organization, with the intention of providing internationally acceptable guidelines for improving emerging arbovirus disease control strategies. Success in these aims should alleviate the suffering and costs encountered during recent decades when Arboviruses have emerged from their sylvatic environment.

  • Factors responsible for the emergence of Arboviruses; strategies, challenges and limitations for their control
    Emerging Microbes & Infections, 2015
    Co-Authors: Guodong Liang, Xiaoyan Gao, Ernest A Gould
    Abstract:

    International audienceSlave trading of Africans to the Americas, during the 16th to the 19th century was responsible for the first recorded emergence in the New World of two arthropod-borne viruses (Arboviruses), yellow fever virus and dengue virus. Many other Arboviruses have since emerged from their sylvatic reservoirs and dispersed globally due to evolving factors that include anthropological behaviour, commercial transportation and land-remediation. Here, we outline some characteristics of these highly divergent Arboviruses, including the variety of life cycles they have developed and the mechanisms by which they have adapted to evolving changes in habitat and host availability. We cite recent examples of virus emergence that exemplify how Arboviruses have exploited the consequences of the modern human lifestyle. Using our current understanding of these viruses, we also attempt to demonstrate some of the limitations encountered in developing control strategies to reduce the impact of future emerging arbovirus diseases. Finally, we present recommendations for development by an international panel of experts reporting directly to World Health Organization, with the intention of providing internationally acceptable guidelines for improving emerging arbovirus disease control strategies. Success in these aims should alleviate the suffering and costs encountered during recent decades when Arboviruses have emerged from their sylvatic environment

Maurício Lacerda Nogueira - One of the best experts on this subject based on the ideXlab platform.

  • Detection of Saint Louis Encephalitis Virus in Dengue-Suspected Cases During a Dengue 3 Outbreak
    Vector-borne and Zoonotic Diseases, 2010
    Co-Authors: Ana Carolina Bernardes Terzian, Adriano Mondini, Roberta Vieira De Moraes Bronzoni, Betânia Paiva Drumond, Bianca Piovezan Ferro, Eliana Márcia Sotello Cabrera, Luis Tadeu Moraes Figueiredo, Francisco Chiaravalloti-neto, Maurício Lacerda Nogueira
    Abstract:

    Abstract Arboviruses are frequently associated with outbreaks in humans and represent a serious public health problem. Among the Brazilian Arboviruses, Mayaro virus, Dengue virus (DENV), Yellow Fever virus, Rocio virus, Saint Louis Encephalitis virus (SLEV), and Oropouche virus are responsible for most of human cases. All these Arboviruses usually produce undistinguishable acute febrile illness, especially in the acute phase of infection. In this study we investigated the presence of Arboviruses in sera of 519 patients presenting acute febrile illness, during a dengue outbreak in Sao Jose do Rio Preto City (Sao Paulo, Brazil). A multiplex-nested RT-polymerase chain reaction assay was applied to detect and identify the main Brazilian Arboviruses (Flavivirus, Alphavirus, and Orthobunyavirus genera). The molecular analysis showed that 365 samples were positive to DENV-3, 5 to DENV-2, and 8 to SLEV. Among the positive samples, one coinfection was detected between DENV-2 and DENV-3. The phylogenetic analysis o...

Erol Fikrig - One of the best experts on this subject based on the ideXlab platform.

  • genetics of war and truce between mosquitos and emerging viruses
    Cell Host & Microbe, 2016
    Co-Authors: Jesse Hwang, Kellie A Jurado, Erol Fikrig
    Abstract:

    Arboviruses have made unexpected reappearances in recent years. Unlike viruses that undergo direct transmission, Arboviruses utilize an arthropod vector (e.g., mosquitos, sandflies, and ticks) to spread throughout human populations. Here, we provide a snapshot of mosquito susceptibility to viral infection using flaviviruses, alphaviruses, and bunyaviruses as examples of emerging pathogens of global health relevance.

Thérèse Atieh - One of the best experts on this subject based on the ideXlab platform.

  • New reverse genetics and transfection methods to rescue Arboviruses in mosquito cells
    Scientific Reports, 2017
    Co-Authors: Thérèse Atieh, Antoine Nougairède, Raphaëlle Klitting, Fabien Aubry, Anna-bella Failloux, Xavier De Lamballerie, Stéphane Priet
    Abstract:

    Reverse genetics is a critical tool to decrypt the biological properties of Arboviruses. However, whilst reverse genetics methods have been usually applied to vertebrate cells, their use in insect cells remains uncommon due to the conjunction of laborious molecular biology techniques and of specific difficulties surrounding the transfection of such cells. To leverage reverse genetics studies in both vertebrate and mosquito cells, we designed an improved DNA transfection protocol for insect cells and then demonstrated that the simple and flexible ISA (Infectious Subgenomic Amplicons) reverse-genetics method can be efficiently applied to both mammalian and mosquito cells to generate in days recombinant infectious positive-stranded RNA viruses belonging to genera Flavivirus (Japanese encephalitis, Yellow fever, West Nile and Zika viruses) and Alphavirus (Chikungunya virus). This method represents an effective option to potentially overcome technological issues related to the study of Arboviruses. Arboviruses (Arthropod-borne viruses) constitute a large group of viruses carried and spread by blood feeding arthropods, especially mosquitoes, ticks and sandflies. They can be transmitted to a variety of vertebrates and are responsible for significant morbidity and mortality amongst humans and farmed animals globally. Arboviral diseases in humans range from mild febrile illness to severe encephalitis or haemorrhagic fever 1. Iterative outbreaks worldwide over the past decades have highlighted the emergence or re-emergence potential of Arboviruses, which are thus considered to be significant public and animal health threats 1–3. Most Arboviruses of public health importance are single-stranded RNA viruses belonging to the families Flavi-, Toga-, or Bunyaviridae. Research focusing on Arboviruses knew dramatic progress thanks to the use of reverse genetics systems allowing the study of virus life cycles, understanding the effect of specific mutations on viral replication or pathogen-esis, and designing new vaccine strategies 4,5. However, these reverse genetics systems focused to date almost exclusively on mammalian cells. Since Arboviruses life cycle involves replication in both invertebrate vectors and vertebrate hosts, a simple and universal reverse genetics method allowing producing recombinant Arboviruses in both vertebrate and arthropod cells would obviously facilitate the study of arbovirus biological properties, of their genomic evolution or cell interactions and restrictions. This awaited knowledge could provide in the future the key elements needed to predict outbreaks and to find efficient therapy. Unfortunately, although most reverse genetics systems proved to be efficient to recover Arboviruses from vertebrate cell lines (for reviews see 4,5), very few studies have reported such systems for arthropod cells and especially for cells from Aedes mosquitoes , one of the most important arbovirus vectors globally 6. Indeed, reverse genetics systems designed for positive-sense single-stranded RNA viruses in Aedes mosquito cells are typically based to date on the lipofection or electroporation of synthetic capped RNA transcripts generated by in vitro transcription from SP6-7–9 or T7 promoter-driven 10–16 full-length viral cDNA constructs. A second system only used marginally and based on the direct transfection of a T7 promoter-driven infectious clone in an Aedes mosquito cell line stably expressing the T7 RNA polymerase was established to produce a minireplicon of the Bunyamwera negative-strand RNA virus 17. Nevertheless, these reverse genetics systems suffer from two main limitations. First, the construction of full-length viral cDNA clones remains difficult and time consuming. To circumvent this issue, we recently developed a novel bacterium-free method of reverse genetics called ISA (Infectious Subgenomic Amplicons) 18. The