The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform

Scott C. Weaver - One of the best experts on this subject based on the ideXlab platform.

  • serologic evidence of various Arboviruses detected in white tailed deer odocoileus virginianus in the united states
    American Journal of Tropical Medicine and Hygiene, 2017
    Co-Authors: Kerri Pedersen, Scott C. Weaver, Eryu Wang, Paul C Wolf, Adam R Randall, Kyle Van Why, Amelia Travassos P A Da Rosa, Thomas Gidlewski
    Abstract:

    White-tailed deer (Odocoileus virginianus) are an abundant mammal with a wide geographic distribution in the United States, which make them good sentinels for monitoring arboviral activity across the country. Exposure to various Arboviruses has been detected in white-tailed deer, typically in conjunction with another diagnostic finding. To better assess the exposure of white-tailed deer to seven Arboviruses, we tested 1,508 sera collected from 2010 to 2016 for antibodies to eastern equine encephalitis (2.5%), Powassan (4.2%), St. Louis encephalitis, (3.7%), West Nile (6.0%), Maguari (19.4%), La Crosse (30.3%), and bluetongue (7.8%) viruses. At least one Arbovirus was detected in 51.3%, and exposure to more than one Arbovirus was identified in 17.6% of the white-tailed deer sampled.

  • Insect-Specific Virus Discovery: Significance for the Arbovirus Community
    Viruses, 2015
    Co-Authors: Bethany G. Bolling, Robert B. Tesh, Scott C. Weaver, Nikos Vasilakis
    Abstract:

    Arthropod-borne viruses (Arboviruses), especially those transmitted by mosquitoes, are a significant cause of morbidity and mortality in humans and animals worldwide. Recent discoveries indicate that mosquitoes are naturally infected with a wide range of other viruses, many within taxa occupied by Arboviruses that are considered insect-specific. Over the past ten years there has been a dramatic increase in the literature describing novel insect-specific virus detection in mosquitoes, which has provided new insights about viral diversity and evolution, including that of Arboviruses. It has also raised questions about what effects the mosquito virome has on Arbovirus transmission. Additionally, the discovery of these new viruses has generated interest in their potential use as biological control agents as well as novel vaccine platforms. The Arbovirus community will benefit from the growing database of knowledge concerning these newly described viral endosymbionts, as their impacts will likely be far reaching.

Alain Kohl - One of the best experts on this subject based on the ideXlab platform.

  • The Antiviral RNAi Response in Vector and Non-vector Cells against Orthobunyaviruses.
    Public Library of Science (PLoS), 2017
    Co-Authors: Isabelle Dietrich, Mick Watson, Melanie Mcfarlane, Alain Kohl, Richard M Elliott, Xiaohong Shi, Anne-lie Blomström, Jessica K Skelton, Esther Schnettler
    Abstract:

    BACKGROUND:Vector arthropods control Arbovirus replication and spread through antiviral innate immune responses including RNA interference (RNAi) pathways. Arbovirus infections have been shown to induce the exogenous small interfering RNA (siRNA) and Piwi-interacting RNA (piRNA) pathways, but direct antiviral activity by these host responses in mosquito cells has only been demonstrated against a limited number of positive-strand RNA Arboviruses. For bunyaviruses in general, the relative contribution of small RNA pathways in antiviral defences is unknown. METHODOLOGY/PRINCIPAL FINDINGS:The genus Orthobunyavirus in the Bunyaviridae family harbours a diverse range of mosquito-, midge- and tick-borne Arboviruses. We hypothesized that differences in the antiviral RNAi response in vector versus non-vector cells may exist and that could influence viral host range. Using Aedes aegypti-derived mosquito cells, mosquito-borne orthobunyaviruses and midge-borne orthobunyaviruses we showed that bunyavirus infection commonly induced the production of small RNAs and the effects of the small RNA pathways on individual viruses differ in specific vector-Arbovirus interactions. CONCLUSIONS/SIGNIFICANCE:These findings have important implications for our understanding of antiviral RNAi pathways and orthobunyavirus-vector interactions and tropism

  • Tick Cell Lines for Study of Crimean-Congo Hemorrhagic Fever Virus and Other Arboviruses
    2015
    Co-Authors: Lesley Bell-sakyi, Alain Kohl, Dennis A. Bente, John K Fazakerley
    Abstract:

    Continuous cell lines derived from many of the vectors of tick-borne Arboviruses of medical and veterinary importance are now available. Their role as tools in Arbovirus research to date is reviewed and their potential application in studies of tick cell responses to virus infection is explored, by comparison with recent progress in understanding mosquito immunity to Arbovirus infection. A preliminary study of propagation of the human pathogen Crimean-Congo hemorrhagic fever virus (CCHFV) in tick cell lines is reported; CCHFV replicated in seven cell lines derived from the ticks Hyalomma anatolicum (a known vector), Amblyomma variegatum, Rhipice-phalus (Boophilus) decoloratus, Rhipicephalus (Boophilus) microplus, and Ixodes ricinus, but not in three cell lines derived from Rhipicephalus appendiculatus and Ornithodoros moubata. This indicates that tick cell lines can be used to study growth of CCHFV in arthropod cells and that there may be species-specific restriction in permissive CCHFV infection at the cellular level. Key Words: Arbovirus—Crimean-Congo hemorrhagic fever virus—innate immunity—tick cell line

  • understanding the wolbachia mediated inhibition of Arboviruses in mosquitoes progress and challenges
    Journal of General Virology, 2014
    Co-Authors: Stephanie M Rainey, Alain Kohl, Pranav N M Shah, Isabelle Dietrich
    Abstract:

    Arthropod-borne viruses (Arboviruses) pose a considerable threat to human and animal health, yet effective control measures have proven difficult to implement, and novel means of controlling their replication in arthropod vectors, such as mosquitoes, are urgently required. One of the most exciting approaches to emerge from research on arthropods is the use of the endosymbiotic intracellular bacterium Wolbachia to control Arbovirus transmission from mosquito to vertebrate. These α-proteobacteria propagate through insects, in part through modulation of host reproduction, thus ensuring spread through species and maintenance in nature. Since it was discovered that Wolbachia endosymbiosis inhibits insect virus replication in Drosophila species, these bacteria have also been shown to inhibit Arbovirus replication and spread in mosquitoes. Importantly, it is not clear how these antiviral effects are mediated. This review will summarize recent work and discuss determinants of antiviral effectiveness that may differ between individual Wolbachia/vector/Arbovirus interactions. We will also discuss the application of this approach to field settings and the associated risks.

  • knockdown of pirna pathway proteins results in enhanced semliki forest virus production in mosquito cells
    Journal of General Virology, 2013
    Co-Authors: Esther Schnettler, Mick Watson, Melanie Mcfarlane, Claire L Donald, Stacey Human, Ricky W C Siu, John K Fazakerley, Alain Kohl
    Abstract:

    The exogenous siRNA pathway is important in restricting Arbovirus infection in mosquitoes. Less is known about the role of the PIWI-interacting RNA pathway, or piRNA pathway, in antiviral responses. Viral piRNA-like molecules have recently been described following infection of mosquitoes and derived cell lines with several Arboviruses. The piRNA pathway has thus been suggested to function as an additional small RNA-mediated antiviral response to the known infection-induced siRNA response. Here we show that piRNA-like molecules are produced following infection with the naturally mosquito-borne Semliki Forest virus in mosquito cell lines. We show that knockdown of piRNA pathway proteins enhances the replication of this Arbovirus and defines the contribution of piRNA pathway effectors, thus characterizing the antiviral properties of the piRNA pathway. In conclusion, Arbovirus infection can trigger the piRNA pathway in mosquito cells, and knockdown of piRNA proteins enhances virus production.

  • advances in dissecting mosquito innate immune responses to Arbovirus infection
    Journal of General Virology, 2009
    Co-Authors: Rennos Fragkoudis, John K Fazakerley, Ghassem Attarzadehyazdi, Anthony Nash, Alain Kohl
    Abstract:

    Arthropod-borne viruses – Arboviruses – are a significant threat to public health. Whilst there is considerable knowledge about Arbovirus interactions with vertebrate immunity, relatively little is known about how vectors such as mosquitoes control Arbovirus infections. In this review, we discuss novel findings in the field of mosquito antiviral responses to Arboviruses, in particular RNA interference, the up-and-coming field of general immune-signalling pathways, and cell death/apoptosis.

Louis Lambrechts - One of the best experts on this subject based on the ideXlab platform.

  • Risk of Arbovirus emergence via bridge vectors: case study of the sylvatic mosquito Aedes malayensis in the Nakai district, Laos
    Scientific Reports, 2020
    Co-Authors: Elliott Miot, Elodie Calvez, Fabien Aubry, Stéphanie Dabo, Marc Grandadam, Sébastien Marcombe, Catherine Oke, James Logan, Paul Brey, Louis Lambrechts
    Abstract:

    Many emerging Arboviruses of global public health importance, such as dengue virus (DENV) and yellow fever virus (YFV), originated in sylvatic transmission cycles involving wild animals and forest-dwelling mosquitoes. Arbovirus emergence in the human population typically results from spillover transmission via bridge vectors, which are competent mosquitoes feeding on both humans and wild animals. Another related, but less studied concern, is the risk of 'spillback' transmission from humans into novel sylvatic cycles. We colonized a sylvatic population of Aedes malayensis from a forested area of the Nakai district in Laos to evaluate its potential as an Arbovirus bridge vector. We found that this Ae. malayensis population was overall less competent for DENV and YFV than an urban population of Aedes aegypti. Olfactometer experiments showed that our Ae. malayensis colony did not display any detectable attraction to human scent in laboratory conditions. The relatively modest vector competence for DENV and YFV, combined with a lack of detectable attraction to human odor, indicate a low potential for this sylvatic Ae. malayensis population to act as an Arbovirus bridge vector. However, we caution that opportunistic blood feeding on humans by sylvatic Ae. malayensis may occasionally contribute to bridge sylvatic and human transmission cycles.

  • virus derived dna drives mosquito vector tolerance to arboviral infection
    Nature Communications, 2016
    Co-Authors: Bertsy Goic, Kenneth A Stapleford, Lionel Frangeul, Aurelien J Doucet, Valerie Gausson, Herve Blanc, Nidia Schemmeljofre, Gael Cristofari, Louis Lambrechts
    Abstract:

    Mosquitoes develop long-lasting viral infections without substantial deleterious effects, despite high viral loads. This makes mosquitoes efficient vectors for emerging viral diseases with enormous burden on public health. How mosquitoes resist and/or tolerate these viruses is poorly understood. Here we show that two species of Aedes mosquitoes infected with two Arboviruses from distinct families (dengue or chikungunya) generate a viral-derived DNA (vDNA) that is essential for mosquito survival and viral tolerance. Inhibition of vDNA formation leads to extreme susceptibility to viral infections, reduction of viral small RNAs due to an impaired immune response, and loss of viral tolerance. Our results highlight an essential role of vDNA in viral tolerance that allows mosquito survival and thus may be important for Arbovirus dissemination and transmission. Elucidating the mechanisms of mosquito tolerance to Arbovirus infection paves the way to conceptualize new antivectorial strategies to selectively eliminate Arbovirus-infected mosquitoes.

Duane J. Gubler - One of the best experts on this subject based on the ideXlab platform.

  • Unexpected outbreaks of Arbovirus infections: lessons learned from the Pacific and tropical America
    The Lancet Infectious Diseases, 2018
    Co-Authors: Didier Musso, Alfonso J. Rodriguez-morales, Jose Eduardo Levi, Van-mai Cao-lormeau, Duane J. Gubler
    Abstract:

    Pandemic Arboviruses have emerged as a major global health problem in the past four decades. Predicting where and when the next Arbovirus epidemic will occur is a challenge, but history suggests that arboviral black swan events (epidemics that are difficult to predict and that have an extreme effect) will continue to occur as urban growth and globalisation expand. We briefly review unexpected Arbovirus epidemics that have occurred in the past 50 years, with emphasis on the American and Pacific regions, to illustrate their unpredictability, and to highlight the need for improved global preparedness, including laboratory-based surveillance, prevention, and control programmes.

  • vertebrate reservoirs of Arboviruses myth synonym of amplifier or reality
    Viruses, 2017
    Co-Authors: Goro Kuno, J S Mackenzie, Sandra Junglen, Z Hubalek, Alexander Plyusnin, Duane J. Gubler
    Abstract:

    The rapid succession of the pandemic of Arbovirus diseases, such as dengue, West Nile fever, chikungunya, and Zika fever, has intensified research on these and other Arbovirus diseases worldwide. Investigating the unique mode of vector-borne transmission requires a clear understanding of the roles of vertebrates. One major obstacle to this understanding is the ambiguity of the Arbovirus definition originally established by the World Health Organization. The paucity of pertinent information on Arbovirus transmission at the time contributed to the notion that vertebrates played the role of reservoir in the Arbovirus transmission cycle. Because this notion is a salient feature of the Arbovirus definition, it is important to reexamine its validity. This review addresses controversial issues concerning vertebrate reservoirs and their role in Arbovirus persistence in nature, examines the genesis of the problem from a historical perspective, discusses various unresolved issues from multiple points of view, assesses the present status of the notion in light of current knowledge, and provides options for a solution to resolve the issue.

  • human Arbovirus infections worldwide
    Annals of the New York Academy of Sciences, 2006
    Co-Authors: Duane J. Gubler
    Abstract:

    Viral diseases transmitted by blood-feeding arthropods (arboviral diseases) are among the most important of the emerging infectious disease public health problems facing the world at the beginning of the third millennium. There are over 534 viruses listed in the Arbovirus catalogue, approximately 134 of which have been shown to cause disease in humans. These are transmitted principally by mosquitoes and ticks. In the last two decades of the twentieth century, a few new arboviral diseases have been recognized. More important, however, is the dramatic resurgence and geographic spread of a number of old diseases that were once effectively controlled. Global demographic and societal changes, and modern transportation have provided the mechanisms for the viruses to break out of their natural ecology and become established in new geographic locations where susceptible arthropod vectors and hosts provide permissive conditions for them to cause major epidemics. West Nile virus is just the the latest example of this type of invasion by exotic viruses. This paper will provide an overview of the medically important Arboviruses and discuss several in more detail as case studies to illustrate our tenuous position as we begin the twenty-first century.

  • Sylvatic transmission of Arboviruses among Bornean orangutans.
    The American Journal of Tropical Medicine and Hygiene, 2001
    Co-Authors: Nathan D. Wolfe, William B. Karesh, Annelisa M. Kilbourn, Edwin J. Bosi, Hasan A. Rahman, Mahedi Andau, Andrew Spielman, Bruce C. Cropp, Duane J. Gubler
    Abstract:

    Wild populations of nonhuman primates live in regions of sylvatic Arbovirus transmission. To assess the status of Arbovirus transmission in Bornean forests and the susceptibility of wild orangutans to arboviral infection, blood samples of wild orangutans, semi-captive orangutans, and humans were examined. Samples were tested by plaque reduction neutralization test for antibodies to viruses representing three families (Flaviviridae, Alphaviridae, and Bunyaviridae), including dengue-2, Japanese encephalitis, Zika, Langat, Tembusu, Sindbis, Chikungunya, and Batai viruses. Both wild and semi-captive orangutan groups as well as local human populations showed serologic evidence of Arbovirus infection. The presence of neutralizing antibodies among wild orangutans strongly suggests the existence of sylvatic cycles for dengue, Japanese encephalitis, and sindbis viruses in North Borneo. The present study demonstrates that orangutans are susceptible to arboviralinfections in the wild, although the impact of arboviral infections on this endangered ape remain unknown.

Edith Chepkorir - One of the best experts on this subject based on the ideXlab platform.

  • Sand Fly–Associated Phlebovirus with Evidence of Neutralizing Antibodies in Humans, Kenya
    Emerging Infectious Diseases, 2019
    Co-Authors: David P. Tchouassi, Marco Marklewitz, Edith Chepkorir, Florian Zirkel, Sheila B. Agha, Caroline Tigoi, Edith Koskei, Christian Drosten, Christian Borgemeister, Baldwyn Torto
    Abstract:

    : We describe a novel virus, designated Ntepes virus (NPV), isolated from sand flies in Kenya. NPV has the characteristic phlebovirus trisegmented genome architecture and is related to, but distinct from, Gabek Forest phlebovirus. Diverse cell cultures derived from wildlife, livestock, and humans were susceptible to NPV, with pronounced permissiveness in swine and rodent cells. NPV infection of newborn mice caused rapid and fatal illness. Permissiveness for NPV replication in sand fly cells, but not mosquito cells, suggests a vector-specific adaptation. Specific neutralizing antibodies were found in 13.9% (26/187) of human serum samples taken at the site of isolation of NPV as well as a disparate site in northeastern Kenya, suggesting a wide distribution. We identify a novel human-infecting Arbovirus and highlight the importance of rural areas in tropical Africa for Arbovirus surveillance as well as extending Arbovirus surveillance to include hematophagous arthropods other than mosquitoes.

  • sand fly associated phlebovirus with evidence of neutralizing antibodies in humans kenya
    Emerging Infectious Diseases, 2019
    Co-Authors: David P. Tchouassi, Marco Marklewitz, Edith Chepkorir, Florian Zirkel, Sheila B. Agha, Caroline Tigoi, Edith Koskei, Christian Drosten, Christian Borgemeister, Baldwyn Torto
    Abstract:

    We describe a novel virus, designated Ntepes virus (NPV), isolated from sand flies in Kenya. NPV has the characteristic phlebovirus trisegmented genome architecture and is related to, but distinct from, Gabek Forest phlebovirus. Diverse cell cultures derived from wildlife, livestock, and humans were susceptible to NPV, with pronounced permissiveness in swine and rodent cells. NPV infection of newborn mice caused rapid and fatal illness. Permissiveness for NPV replication in sand fly cells, but not mosquito cells, suggests a vector-specific adaptation. Specific neutralizing antibodies were found in 13.9% (26/187) of human serum samples taken at the site of isolation of NPV as well as a disparate site in northeastern Kenya, suggesting a wide distribution. We identify a novel human-infecting Arbovirus and highlight the importance of rural areas in tropical Africa for Arbovirus surveillance as well as extending Arbovirus surveillance to include hematophagous arthropods other than mosquitoes.

  • mosquito borne Arbovirus surveillance at selected sites in diverse ecological zones of kenya 2007 2012
    Virology Journal, 2013
    Co-Authors: Caroline Ochieng, Edith Chepkorir, Joel Lutomiah, Albina Makio, Hellen Koka, Santos Yalwala, James Mutisya, Lillian Musila, Samoel Khamadi
    Abstract:

    Background Increased frequency of Arbovirus outbreaks in East Africa necessitated the determination of distribution of risk by entomologic Arbovirus surveillance. A systematic vector surveillance programme spanning 5 years and covering 11 sites representing seven of the eight provinces in Kenya and located in diverse ecological zones was carried out.

  • mosquito borne Arbovirus surveillance at selected sites in diverse ecological zones of kenya 2007 2012
    Virology Journal, 2013
    Co-Authors: Caroline Ochieng, Edith Chepkorir, Joel Lutomiah, Albina Makio, Hellen Koka, Santos Yalwala, James Mutisya, Lillian Musila, Samoel Khamadi
    Abstract:

    Increased frequency of Arbovirus outbreaks in East Africa necessitated the determination of distribution of risk by entomologic Arbovirus surveillance. A systematic vector surveillance programme spanning 5 years and covering 11 sites representing seven of the eight provinces in Kenya and located in diverse ecological zones was carried out. Mosquitoes were sampled bi-annually during the wet seasons and screened for Arboviruses. Mosquitoes were identified to species, pooled by species, collection date and site and screened for Arboviruses by isolation in cell culture and/or RT-PCR screening and sequencing. Over 450,000 mosquitoes in 15,890 pools were screened with 83 viruses being detected/isolated that include members of the alphavirus, flavivirus and orthobunyavirus genera many of which are known to be of significant public health importance in the East African region. These include West Nile, Ndumu, Sindbis, Bunyamwera, Pongola and Usutu viruses detected from diverse sites. Ngari virus, which was associated with hemorrhagic fever in northern Kenya in 1997/98 was isolated from a pool of Anopheles funestus sampled from Tana-delta and from Aedes mcintoshi from Garissa. Insect only flaviviruses previously undescribed in Kenya were also isolated in the coastal site of Rabai. A flavivirus most closely related to the Chaoyang virus, a new virus recently identified in China and two isolates closely related to Quang Binh virus previously unreported in Kenya were also detected. Active transmission of Arboviruses of public health significance continues in various parts of the country with possible undetermined human impact. Arbovirus activity was highest in the pastoralist dominated semi-arid to arid zones sites of the country where 49% of the viruses were isolated suggesting a role of animals as amplifiers and indicating the need for improved Arbovirus disease diagnosis among pastoral communities.