The Experts below are selected from a list of 128181 Experts worldwide ranked by ideXlab platform
Scott C. Weaver - One of the best experts on this subject based on the ideXlab platform.
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RESEARCH Experimental Everglades Virus Infection of Cotton Rats (Sigmodon hispidus)
2013Co-Authors: Lark L. Coffey, Anne Sophie Carrara, Slobodan Paessler, Michelle L. Haynie, Robert D. Bradley, Robert B. Tesh, Scott C. WeaverAbstract:Everglades virus (EVEV), an alphavirus in the Venezuelan Equine encephalitis (VEE) serocomplex, circulates among rodents and vector mosquitoes and infects humans, causing a febrile disease sometimes accompanied by neurologic manifestations. EVEV circulates near metropolitan Miami, which indicates the potential for substantial human disease, should outbreaks arise. We characterized EVEV infection of cotton rats in South Florida, USA to validate their role in enzootic transmission. To evaluate whether the viremia induced in cotton rat populations regulates EVEV distribution, we also infected rats from a non–EVEV-endemic area. Viremia levels developed in rats from both localities that exceeded the threshold for infection of the vector. Most animals survived infection with no signs of illness, despite virus invasion of the brain and the development of mild encephalitis. Understanding the mechanisms by which EVEV-infected cotton rats resist clinical disease may be useful in developing VEE therapeutics for Equines and humans. Everglades virus (EVEV; Togaviridae: Alphavirus) circulates among rodents and vector mosquitoes in South Florida and can tangentially infect humans, causing a febrile disease with occasional neurologic signs. The most closely related Venezuelan Equine encephalitis (VEE) complex viruses, enzootic subtype ID strains, are the progenitors of subtype IAB and IC strains responsible for major epidemics and epizootics (1). This relationship raises the possibility of epidemic emergence in South Florida, involving mutations in the EVEV genome, with serious public health consequences for>2 million people in metropolita
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Vector competence of eastern and western forms of Psorophora columbiae (Diptera: Culicidae) mosquitoes for enzootic and epizootic Venezuelan Equine encephalitis virus.
The American journal of tropical medicine and hygiene, 2008Co-Authors: Abelardo C. Moncayo, Wenli Kang, Gregory C. Lanzaro, Arnoldo Orozco, Armando Ulloa, Juan I. Arredondo-jimenez, Scott C. WeaverAbstract:Venezuelan Equine encephalitis virus (VEEV) continues to circulate enzootically in Mexico with the potential to re-emerge and cause disease in Equines and humans in North America. We infected two geographically distinct mosquito populations of eastern Psorophora columbiae form columbiae (Chiapas, Mexico and Texas, United States) and one mosquito population of western Psorophora columbiae form toltecum (California, United States) with epizootic and enzootic IE VEEV and epizootic IAB VEEV. We detected no differences between epizootic and enzootic IE viruses in their ability to infect any of the mosquito populations analyzed, which suggested that neither species selects for epizootic IE viruses. Psorophora columbiae f. columbiae (Texas) were significantly less susceptible to infection by epizootic IE than Ps. columbiae f. columbiae (Mexico). Psorophora columbiae f. toltecum populations were more susceptible than Ps. columbiae f. columbiae populations to epizootic IE and IAB viruses.
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experimental everglades virus infection of cotton rats sigmodon hispidus
Emerging Infectious Diseases, 2004Co-Authors: Lark L. Coffey, Anne Sophie Carrara, Slobodan Paessler, Michelle L. Haynie, Robert D. Bradley, Robert B. Tesh, Scott C. WeaverAbstract:Everglades virus (EVEV), an alphavirus in the Venezuelan Equine encephalitis (VEE) serocomplex, circulates among rodents and vector mosquitoes and infects humans, causing a febrile disease sometimes accompanied by neurologic manifestations. EVEV circulates near metropolitan Miami, which indicates the potential for substantial human disease, should outbreaks arise. We characterized EVEV infection of cotton rats in South Florida, USA to validate their role in enzootic transmission. To evaluate whether the viremia induced in cotton rat populations regulates EVEV distribution, we also infected rats from a non–EVEV-endemic area. Viremia levels developed in rats from both localities that exceeded the threshold for infection of the vector. Most animals survived infection with no signs of illness, despite virus invasion of the brain and the development of mild encephalitis. Understanding the mechanisms by which EVEV-infected cotton rats resist clinical disease may be useful in developing VEE therapeutics for Equines and humans.
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generation and characterization of closely related epizootic and enzootic infectious cdna clones for studying interferon sensitivity and emergence mechanisms of venezuelan Equine encephalitis virus
Journal of Virology, 2004Co-Authors: Michael Anishchenko, Anne Sophie Carrara, Ivorlyne P Greene, Slobodan Paessler, Patricia V Aguilar, Scott C. WeaverAbstract:Venezuelan Equine encephalitis virus (VEEV) is a reemerging pathogen and a continuing threat to humans and Equines in the Americas. Identification of the genetic determinants that enable epizootic VEEV strains to arise and exploit Equines as amplification hosts to cause widespread human disease is pivotal to understanding VEE emergence. The sensitivity to murine alpha/beta interferon-mediated antiviral activity was previously correlated to the epizootic phenotype of several VEEV strains. Infectious cDNA clones were generated from an epizootic subtype IC VEEV strain (SH3) isolated during the 1992 Venezuelan outbreak and a closely related enzootic, sympatric subtype ID strain (ZPC738). These VEEV strains had low-cell-culture-passage histories and differed by only 12 amino acids in the nonstructural and structural proteins. Rescued viruses showed similar growth kinetics to their parent viruses in several cell lines, and murine infections resulted in comparable viremia and disease. Unlike what was found in other studies of epizootic and enzootic VEEV strains, the sensitivities to murine alpha/beta interferon did not differ appreciably between these epizootic versus enzootic strains, calling into question the reliability of interferon sensitivity as a marker of epizootic potential.
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venezuelan Equine encephalitis
Annual Review of Entomology, 2003Co-Authors: Scott C. Weaver, Roberto Barrera, Jorge Boshell, Cristina Ferro, Juan Carlos NavarroAbstract:Venezuelan Equine encephalitis virus (VEEV) remains a naturally emerging disease threat as well as a highly developed biological weapon. Recently, progress has been made in understanding the complex ecological and viral genetic mechanisms that coincide in time and space to generate outbreaks. Enzootic, Equine avirulent, serotype ID VEEV strains appear to alter their serotype to IAB or IC, and their vertebrate and mosquito host range, to mediate repeated VEE emergence via mutations in the E2 envelope glycoprotein that represent convergent evolution. Adaptation to Equines results in highly efficient amplification, which results in human disease. Although epizootic VEEV strains are opportunistic in their use of mosquito vectors, the most widespread outbreaks appear to involve specific adaptation to Ochlerotatus taeniorhynchus, the most common vector in many coastal areas. In contrast, enzootic VEEV strains are highly specialized and appear to utilize vectors exclusively in the Spissipes section of the Culex (Melanoconion) subgenus.
Slobodan Paessler - One of the best experts on this subject based on the ideXlab platform.
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Pathogenesis of Venezuelan Equine encephalitis.
Veterinary microbiology, 2013Co-Authors: Katherine G Taylor, Slobodan PaesslerAbstract:Equine encephalids have high mortality rates and represent a significant zoonotic public health threat. Of these the most pathogenic viruses to equids are the alphaviruses in the family Togaviridae. The focus of this review Venezualen Equine encephalitis virus (VEEV) has caused the most widespread and recent epidemic outbreaks of disease. Circulation in naturally occuring rodent-mosquito cycles, results in viral spread to both human and Equine populations. However, Equines develop a high titer viremia and can transmit the virus back to mosquito populations. As such, the early recognition and control of viral infection in Equine populations is strongly associated with prevention of epidemic spread of the virus and limiting of disease incidence in human populations. This review will address identification and pathogenesis of VEEV in equids vaccination and treatment options, and current research for drug and vaccine development.
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RESEARCH Experimental Everglades Virus Infection of Cotton Rats (Sigmodon hispidus)
2013Co-Authors: Lark L. Coffey, Anne Sophie Carrara, Slobodan Paessler, Michelle L. Haynie, Robert D. Bradley, Robert B. Tesh, Scott C. WeaverAbstract:Everglades virus (EVEV), an alphavirus in the Venezuelan Equine encephalitis (VEE) serocomplex, circulates among rodents and vector mosquitoes and infects humans, causing a febrile disease sometimes accompanied by neurologic manifestations. EVEV circulates near metropolitan Miami, which indicates the potential for substantial human disease, should outbreaks arise. We characterized EVEV infection of cotton rats in South Florida, USA to validate their role in enzootic transmission. To evaluate whether the viremia induced in cotton rat populations regulates EVEV distribution, we also infected rats from a non–EVEV-endemic area. Viremia levels developed in rats from both localities that exceeded the threshold for infection of the vector. Most animals survived infection with no signs of illness, despite virus invasion of the brain and the development of mild encephalitis. Understanding the mechanisms by which EVEV-infected cotton rats resist clinical disease may be useful in developing VEE therapeutics for Equines and humans. Everglades virus (EVEV; Togaviridae: Alphavirus) circulates among rodents and vector mosquitoes in South Florida and can tangentially infect humans, causing a febrile disease with occasional neurologic signs. The most closely related Venezuelan Equine encephalitis (VEE) complex viruses, enzootic subtype ID strains, are the progenitors of subtype IAB and IC strains responsible for major epidemics and epizootics (1). This relationship raises the possibility of epidemic emergence in South Florida, involving mutations in the EVEV genome, with serious public health consequences for>2 million people in metropolita
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experimental everglades virus infection of cotton rats sigmodon hispidus
Emerging Infectious Diseases, 2004Co-Authors: Lark L. Coffey, Anne Sophie Carrara, Slobodan Paessler, Michelle L. Haynie, Robert D. Bradley, Robert B. Tesh, Scott C. WeaverAbstract:Everglades virus (EVEV), an alphavirus in the Venezuelan Equine encephalitis (VEE) serocomplex, circulates among rodents and vector mosquitoes and infects humans, causing a febrile disease sometimes accompanied by neurologic manifestations. EVEV circulates near metropolitan Miami, which indicates the potential for substantial human disease, should outbreaks arise. We characterized EVEV infection of cotton rats in South Florida, USA to validate their role in enzootic transmission. To evaluate whether the viremia induced in cotton rat populations regulates EVEV distribution, we also infected rats from a non–EVEV-endemic area. Viremia levels developed in rats from both localities that exceeded the threshold for infection of the vector. Most animals survived infection with no signs of illness, despite virus invasion of the brain and the development of mild encephalitis. Understanding the mechanisms by which EVEV-infected cotton rats resist clinical disease may be useful in developing VEE therapeutics for Equines and humans.
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generation and characterization of closely related epizootic and enzootic infectious cdna clones for studying interferon sensitivity and emergence mechanisms of venezuelan Equine encephalitis virus
Journal of Virology, 2004Co-Authors: Michael Anishchenko, Anne Sophie Carrara, Ivorlyne P Greene, Slobodan Paessler, Patricia V Aguilar, Scott C. WeaverAbstract:Venezuelan Equine encephalitis virus (VEEV) is a reemerging pathogen and a continuing threat to humans and Equines in the Americas. Identification of the genetic determinants that enable epizootic VEEV strains to arise and exploit Equines as amplification hosts to cause widespread human disease is pivotal to understanding VEE emergence. The sensitivity to murine alpha/beta interferon-mediated antiviral activity was previously correlated to the epizootic phenotype of several VEEV strains. Infectious cDNA clones were generated from an epizootic subtype IC VEEV strain (SH3) isolated during the 1992 Venezuelan outbreak and a closely related enzootic, sympatric subtype ID strain (ZPC738). These VEEV strains had low-cell-culture-passage histories and differed by only 12 amino acids in the nonstructural and structural proteins. Rescued viruses showed similar growth kinetics to their parent viruses in several cell lines, and murine infections resulted in comparable viremia and disease. Unlike what was found in other studies of epizootic and enzootic VEEV strains, the sensitivities to murine alpha/beta interferon did not differ appreciably between these epizootic versus enzootic strains, calling into question the reliability of interferon sensitivity as a marker of epizootic potential.
Rosa Alba Salas - One of the best experts on this subject based on the ideXlab platform.
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Emergence of a new epidemic/epizootic Venezuelan Equine encephalitis virus in South America
Proceedings of the National Academy of Sciences of the United States of America, 1995Co-Authors: Rebeca Rico-hesse, Scott C. Weaver, Julieta De Siger, Gladys Medina, Rosa Alba SalasAbstract:One of the most important questions in arbovirology concerns the origin of epidemic Venezuelan Equine encephalitis (VEE) viruses; these viruses caused periodic, extensive epidemics/epizootics in the Americas from 1938-1973 (reaching the United States in 1971) but had recently been presumed extinct. We have documented the 1992 emergence of a new epidemic/epizootic VEE virus in Venezuela. Phylogenetic analysis of strains isolated during two outbreaks indicated that the new epidemic/epizootic virus(es) evolved recently from an enzootic VEE virus in northern South America. These results suggest continued emergence of epizootic VEE viruses; surveillance of enzootic viruses and routine vaccination of Equines should therefore be resumed.
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emergence of a new epidemic epizootic venezuelan Equine encephalitis virus in south america
Proceedings of the National Academy of Sciences of the United States of America, 1995Co-Authors: Rebeca Ricohesse, Scott C. Weaver, Julieta De Siger, Gladys Medina, Rosa Alba SalasAbstract:One of the most important questions in arbovirology concerns the origin of epidemic Venezuelan Equine encephalitis (VEE) viruses; these viruses caused periodic, extensive epidemics/epizootics in the Americas from 1938-1973 (reaching the United States in 1971) but had recently been presumed extinct. We have documented the 1992 emergence of a new epidemic/epizootic VEE virus in Venezuela. Phylogenetic analysis of strains isolated during two outbreaks indicated that the new epidemic/epizootic virus(es) evolved recently from an enzootic VEE virus in northern South America. These results suggest continued emergence of epizootic VEE viruses; surveillance of enzootic viruses and routine vaccination of Equines should therefore be resumed.
Ryan O’handley - One of the best experts on this subject based on the ideXlab platform.
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Systematic review of gastrointestinal nematodes of horses from Australia
Parasites & Vectors, 2019Co-Authors: Muhammad A. Saeed, Ian Beveridge, Ghazanfar Abbas, Anne Beasley, Jenni Bauquier, Edwina Wilkes, Caroline Jacobson, Kris J. Hughes, Charles El-hage, Ryan O’handleyAbstract:Background Equine gastrointestinal nematodes (GINs) have been the subject of intermittent studies in Australia over the past few decades. However, comprehensive information on the epidemiology of Equine GINs, the efficacy of available anthelmintic drugs and the prevalence of anthelmintic resistance (AR) in Australasia is lacking. Herein, we have systematically reviewed existing knowledge on the horse GINs recorded in Australia, and main aspects of their pathogeneses, epidemiology, diagnoses, treatment and control. Methods Six electronic databases were searched for publications on GINs of Australian horses that met our inclusion criteria for the systematic review. Subsets of publications were subjected to review epidemiology, diagnoses, pathogeneses, treatment and control of GINs of horses from Australia. Results A total of 51 articles published between 1950 to 2018 were included. The main GINs reported in Australian horses were cyathostomins (at least 28 species), Draschia megastoma , Habronema muscae , H. majus , Oxyuris equi , Parascaris equorum , Strongyloides westeri and Trichostrongylus axei across different climatic regions of Queensland, New South Wales, Victoria, and Western Australia. Nematodes are diagnosed based on the traditional McMaster egg counting technique, though molecular markers to characterise common GINs of Equines were characterised in 1990s. The use of anthelmintic drugs remains the most widely-used strategy for controlling Equine GIN parasites in Australia; however, the threshold of faecal egg count that should trigger treatment in horses, remains controversial. Furthermore, anthelmintic resistance within GIN population of horses is becoming a common problem in Australia. Conclusions Although GINs infecting Australian horses have been the subject of occasional studies over the past few decades, the effective control of GIN infections is hampered by a generalised lack of knowledge in various disciplines of Equine parasitology. Therefore, coordinated and focused research is required to fill our knowledge gaps in these areas to maximise Equine health and minimise economic losses associated with the parasitic infections in Australia.
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Systematic review of gastrointestinal nematodes of horses from Australia
Parasites & Vectors, 2019Co-Authors: Muhammad A. Saeed, Ian Beveridge, Ghazanfar Abbas, Anne Beasley, Jenni Bauquier, Edwina Wilkes, Caroline Jacobson, Kris J. Hughes, Charles El-hage, Ryan O’handleyAbstract:Background Equine gastrointestinal nematodes (GINs) have been the subject of intermittent studies in Australia over the past few decades. However, comprehensive information on the epidemiology of Equine GINs, the efficacy of available anthelmintic drugs and the prevalence of anthelmintic resistance (AR) in Australasia is lacking. Herein, we have systematically reviewed existing knowledge on the horse GINs recorded in Australia, and main aspects of their pathogeneses, epidemiology, diagnoses, treatment and control. Methods Six electronic databases were searched for publications on GINs of Australian horses that met our inclusion criteria for the systematic review. Subsets of publications were subjected to review epidemiology, diagnoses, pathogeneses, treatment and control of GINs of horses from Australia. Results A total of 51 articles published between 1950 to 2018 were included. The main GINs reported in Australian horses were cyathostomins (at least 28 species), Draschia megastoma , Habronema muscae , H. majus , Oxyuris equi , Parascaris equorum , Strongyloides westeri and Trichostrongylus axei across different climatic regions of Queensland, New South Wales, Victoria, and Western Australia. Nematodes are diagnosed based on the traditional McMaster egg counting technique, though molecular markers to characterise common GINs of Equines were characterised in 1990s. The use of anthelmintic drugs remains the most widely-used strategy for controlling Equine GIN parasites in Australia; however, the threshold of faecal egg count that should trigger treatment in horses, remains controversial. Furthermore, anthelmintic resistance within GIN population of horses is becoming a common problem in Australia. Conclusions Although GINs infecting Australian horses have been the subject of occasional studies over the past few decades, the effective control of GIN infections is hampered by a generalised lack of knowledge in various disciplines of Equine parasitology. Therefore, coordinated and focused research is required to fill our knowledge gaps in these areas to maximise Equine health and minimise economic losses associated with the parasitic infections in Australia.
Aymeric Hans - One of the best experts on this subject based on the ideXlab platform.
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Epidemiology and molecular detection of Equine herpesviruses in western Algeria in 2011
Veterinary Microbiology, 2017Co-Authors: Farouk Laabassi, Aymeric Hans, Erika Hue, Christine Fortier, Elodie Morilland, Loïc Legrand, Stéphane PronostAbstract:An episode of acute Equine respiratory infection was reported in western Algeria (Tiaret province) between February and March 2011, affecting a large population of horses. Nasal swabs (n=100) were taken from horses aged between 1 and 27 years, presenting with cough and mucopurulent nasal discharge. The prevalence of Equine respiratory virus infections was examined using quantitative polymerase chain reaction (qPCR). One, or more, of four Equine respiratory viruses were detected in the nasal swabs of 90 of 100 horses (90%) and the detection rate of Equine herpesvirus type 1 (EHV-1), Equine herpesvirus type 4 (EHV-4), Equine herpesvirus type 2 (EHV-2) and Equine herpesvirus type 5 (EHV-5) were 2%, 14%, 90% and 75%, respectively. Equine influenza virus and Equine arteritis virus were not detected in any samples. Among the 90 infected horses, 70 were coinfected with EHV-2 and EHV-5 and 14 others were co-infected with EHV-4, EHV-2 and EHV-5. The present study shows a positivity rate of 97.3% for EHV-5 in young horses aged
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Detection of West Nile Virus and other common Equine viruses in three locations from the Leeward Islands, West Indies
Acta Tropica, 2017Co-Authors: Pompei Bolfa, Isaac Jeon, Amanda Loftis, Teresa Leslie, Silvia Marchi, Fortune Sithole, Cécile Beck, Sylvie Lecollinet, Stephan Zientara, Aymeric HansAbstract:Equines in the West Indies are used for recreational purposes, tourism industry, racing and agriculture or can be found in feral populations. Little is known in the Caribbean basin about the prevalence of some major Equine infectious diseases, some with zoonotic potential, listed as reportable by the OIE. Our objective was to study the prevalence of antibodies for West Nile Virus (WNV), Equine Herpes Virus-1 and 4 (EHV-1 and EHV-4), Equine Influenza (EI), Equine Viral Arteritis (EVA) and Equine Infectious Anemia Virus (EIAV) using a retrospective serological convenience study. We used 180 Equine serum samples, 140 from horses and 40 from donkeys in St. Kitts, Nevis, and Sint Eustatius, collected between 2006 and 2015 that were tested with ELISA kits and virus neutralization (for WNV and EVA). Combining ELISA with virus neutralization testing, 25 (13.8%) Equine sera were WNV positive (a mixture of indigenous and imported Equines) and 3 sera (1.6%) showed doubtful results. For EHV-1, 41 Equines (23.7%), mean age 6.7 years, were seropositive. For EHV-4, 138 Equines were found seropositive (82.8%), mean age 6.3 years. For El, 49 Equines (27.2%), mean age 7.5 years, were seropositive on ELISA, some previously vaccinated horses. No antibodies against EAV were found on virus neutralization testing, although one animal (0.6%), was EAV positive on ELISA. All samples were EIAV negative. The seroprevalence for EHV-1 and EHV-4 is similar to other parts of the world. For the first time in the study location serologic evidence of antibodies against WNV and EI is reported. This was found in both indigenous and imported animals, highlighting the need for developing proper surveillance plans based on complementary methods of virus detection. Further studies will be needed to define the prevalence, rates of transmission, characterize local virus strains, and study their impact on these populations.
