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Marinho MDS, Ferreira GM, Grosche VR, Nicolau-Junior N, Campos TDL, Santos IA, Jardim ACG. Evolutionary Profile of Mayaro Virus in the Americas: An Update into Genome Variability. Viruses 2024; 16:809. [PMID: 38793690 PMCID: PMC11126029 DOI: 10.3390/v16050809] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2024] [Revised: 05/15/2024] [Accepted: 05/19/2024] [Indexed: 05/26/2024] Open
Abstract
The Mayaro virus (MAYV) is an arbovirus with emerging potential, though with a limited understanding of its epidemiology and evolution due to the lack of studies and surveillance. Here, we investigated 71 MAYV genome sequences from the Americas available at GenBank and characterized the phylogenetic relationship among virus strains. A phylogenetic analysis showed that sequences were grouped according to the genotypes L, D, and N. Genotype D sequences were closely related to sequences collected in adjacent years and from their respective countries, suggesting that isolates may have originated from circulating lineages. The coalescent analysis demonstrated similar results, indicating the continuous circulation of the virus between countries as well. An unidentified sequence from the USA was grouped with genotype D, suggesting the insertion of this genotype in the country. Furthermore, the recombination analysis detected homologous and three heterologous hybrids which presented an insertion into the nsP3 protein. Amino acid substitutions among sequences indicated selective pressure sites, suggesting viral adaptability. This also impacted the binding affinity between the E1-E2 protein complex and the Mxra8 receptor, associated with MAYV entry into human cells. These results provide information for a better understanding of genotypes circulating in the Americas.
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Affiliation(s)
- Mikaela dos Santos Marinho
- Institute of Biomedical Sciences, ICBIM, Federal University of Uberlândia, Avenida Amazonas, 4C- Room 216, Umuarama, Uberlândia 38405-319, MG, Brazil; (M.d.S.M.); (G.M.F.); (V.R.G.)
| | - Giulia Magalhães Ferreira
- Institute of Biomedical Sciences, ICBIM, Federal University of Uberlândia, Avenida Amazonas, 4C- Room 216, Umuarama, Uberlândia 38405-319, MG, Brazil; (M.d.S.M.); (G.M.F.); (V.R.G.)
| | - Victória Riquena Grosche
- Institute of Biomedical Sciences, ICBIM, Federal University of Uberlândia, Avenida Amazonas, 4C- Room 216, Umuarama, Uberlândia 38405-319, MG, Brazil; (M.d.S.M.); (G.M.F.); (V.R.G.)
- Institute of Biosciences, Humanities and Exact Sciences (Ibilce), São Paulo State University (Unesp), Campus São José do Rio Preto, São José do Rio Preto 15054-000, SP, Brazil
| | - Nilson Nicolau-Junior
- Institute of Biotechnology, Federal University of Uberlândia, Uberlândia 38405-319, MG, Brazil;
| | - Túlio de Lima Campos
- Aggeu Magalhães Institute (Fiocruz), Bioinformatics Core Facility, Recife 50740-465, PE, Brazil;
| | - Igor Andrade Santos
- Institute of Biomedical Sciences, ICBIM, Federal University of Uberlândia, Avenida Amazonas, 4C- Room 216, Umuarama, Uberlândia 38405-319, MG, Brazil; (M.d.S.M.); (G.M.F.); (V.R.G.)
| | - Ana Carolina Gomes Jardim
- Institute of Biomedical Sciences, ICBIM, Federal University of Uberlândia, Avenida Amazonas, 4C- Room 216, Umuarama, Uberlândia 38405-319, MG, Brazil; (M.d.S.M.); (G.M.F.); (V.R.G.)
- Institute of Biosciences, Humanities and Exact Sciences (Ibilce), São Paulo State University (Unesp), Campus São José do Rio Preto, São José do Rio Preto 15054-000, SP, Brazil
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Maloney BE, Carpio KL, Bilyeu AN, Saunders DRD, Park SL, Pohl AE, Ball NC, Raetz JL, Huang CY, Higgs S, Barrett ADT, Roman-Sosa G, Kenney JL, Vanlandingham DL, Huang YJS. Identification of the flavivirus conserved residues in the envelope protein hinge region for the rational design of a candidate West Nile live-attenuated vaccine. NPJ Vaccines 2023; 8:172. [PMID: 37932282 PMCID: PMC10628263 DOI: 10.1038/s41541-023-00765-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2023] [Accepted: 10/18/2023] [Indexed: 11/08/2023] Open
Abstract
The flavivirus envelope protein is a class II fusion protein that drives flavivirus-cell membrane fusion. The membrane fusion process is triggered by the conformational change of the E protein from dimer in the virion to trimer, which involves the rearrangement of three domains, EDI, EDII, and EDIII. The movement between EDI and EDII initiates the formation of the E protein trimer. The EDI-EDII hinge region utilizes four motifs to exert the hinge effect at the interdomain region and is crucial for the membrane fusion activity of the E protein. Using West Nile virus (WNV) NY99 strain derived from an infectious clone, we investigated the role of eight flavivirus-conserved hydrophobic residues in the EDI-EDII hinge region in the conformational change of E protein from dimer to trimer and viral entry. Single mutations of the E-A54, E-I130, E-I135, E-I196, and E-Y201 residues affected infectivity. Importantly, the E-A54I and E-Y201P mutations fully attenuated the mouse neuroinvasive phenotype of WNV. The results suggest that multiple flavivirus-conserved hydrophobic residues in the EDI-EDII hinge region play a critical role in the structure-function of the E protein and some contribute to the virulence phenotype of flaviviruses as demonstrated by the attenuation of the mouse neuroinvasive phenotype of WNV. Thus, as a proof of concept, residues in the EDI-EDII hinge region are proposed targets to engineer attenuating mutations for inclusion in the rational design of candidate live-attenuated flavivirus vaccines.
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Affiliation(s)
- Bailey E Maloney
- Department of Diagnostic Medicine/Pathobiology, College of Veterinary Medicine, Kansas State University, Manhattan, KS, 66506, USA
- Biosecurity Research Institute, Kansas State University, Manhattan, KS, 66506, USA
| | - Kassandra L Carpio
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, TX, 77555, USA
- Sealy Institute for Vaccine Sciences, University of Texas Medical Branch, Galveston, TX, 77555, USA
| | - Ashley N Bilyeu
- Department of Diagnostic Medicine/Pathobiology, College of Veterinary Medicine, Kansas State University, Manhattan, KS, 66506, USA
- Biosecurity Research Institute, Kansas State University, Manhattan, KS, 66506, USA
| | - Danielle R D Saunders
- Department of Diagnostic Medicine/Pathobiology, College of Veterinary Medicine, Kansas State University, Manhattan, KS, 66506, USA
- Biosecurity Research Institute, Kansas State University, Manhattan, KS, 66506, USA
- Department of Biology, Dean of Faculty, United States Air Force Academy, Colorado Springs, CO, 80840, USA
| | - So Lee Park
- Department of Diagnostic Medicine/Pathobiology, College of Veterinary Medicine, Kansas State University, Manhattan, KS, 66506, USA
- Biosecurity Research Institute, Kansas State University, Manhattan, KS, 66506, USA
| | - Adrienne E Pohl
- Department of Diagnostic Medicine/Pathobiology, College of Veterinary Medicine, Kansas State University, Manhattan, KS, 66506, USA
- Biosecurity Research Institute, Kansas State University, Manhattan, KS, 66506, USA
| | - Natalia Costa Ball
- Department of Diagnostic Medicine/Pathobiology, College of Veterinary Medicine, Kansas State University, Manhattan, KS, 66506, USA
- Biosecurity Research Institute, Kansas State University, Manhattan, KS, 66506, USA
| | - Janae L Raetz
- Division of Vector-borne Diseases, Centers for Disease Control and Prevention, Fort Collins, CO, 80521, USA
| | - Claire Y Huang
- Division of Vector-borne Diseases, Centers for Disease Control and Prevention, Fort Collins, CO, 80521, USA
| | - Stephen Higgs
- Department of Diagnostic Medicine/Pathobiology, College of Veterinary Medicine, Kansas State University, Manhattan, KS, 66506, USA
- Biosecurity Research Institute, Kansas State University, Manhattan, KS, 66506, USA
| | - Alan D T Barrett
- Sealy Institute for Vaccine Sciences, University of Texas Medical Branch, Galveston, TX, 77555, USA
- Department of Pathology, University of Texas Medical Branch, Galveston, TX, 77555, USA
| | - Gleyder Roman-Sosa
- Department of Diagnostic Medicine/Pathobiology, College of Veterinary Medicine, Kansas State University, Manhattan, KS, 66506, USA
- Institute of Virology, University of Veterinary Medicine Hanover, Foundation, Buentewg 17, 30559, Hanover, Germany
| | - Joanie L Kenney
- Division of Vector-borne Diseases, Centers for Disease Control and Prevention, Fort Collins, CO, 80521, USA
| | - Dana L Vanlandingham
- Department of Diagnostic Medicine/Pathobiology, College of Veterinary Medicine, Kansas State University, Manhattan, KS, 66506, USA
- Biosecurity Research Institute, Kansas State University, Manhattan, KS, 66506, USA
| | - Yan-Jang S Huang
- Department of Diagnostic Medicine/Pathobiology, College of Veterinary Medicine, Kansas State University, Manhattan, KS, 66506, USA.
- Biosecurity Research Institute, Kansas State University, Manhattan, KS, 66506, USA.
- Department of Microbiology and Immunology and SUNY Center for Vector-Borne Diseases, Institute of Global Health and Translation Science, Upstate Medical University, Syracuse, NY, 13210, USA.
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van Zyl GU. New Technological Developments in Identification and Monitoring of New and Emerging Infections. ENCYCLOPEDIA OF INFECTION AND IMMUNITY 2022. [PMCID: PMC8291697 DOI: 10.1016/b978-0-12-818731-9.00094-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Snyder RE, Feiszli T, Foss L, Messenger S, Fang Y, Barker CM, Reisen WK, Vugia DJ, Padgett KA, Kramer VL. West Nile virus in California, 2003-2018: A persistent threat. PLoS Negl Trop Dis 2020; 14:e0008841. [PMID: 33206634 PMCID: PMC7710070 DOI: 10.1371/journal.pntd.0008841] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2020] [Revised: 12/02/2020] [Accepted: 09/24/2020] [Indexed: 02/06/2023] Open
Abstract
The California Arbovirus Surveillance Program was initiated over 50 years ago to track endemic encephalitides and was enhanced in 2000 to include West Nile virus (WNV) infections in humans, mosquitoes, sentinel chickens, dead birds and horses. This comprehensive statewide program is a function of strong partnerships among the California Department of Public Health (CDPH), the University of California, and local vector control and public health agencies. This manuscript summarizes WNV surveillance data in California since WNV was first detected in 2003 in southern California. From 2003 through 2018, 6,909 human cases of WNV disease, inclusive of 326 deaths, were reported to CDPH, as well as 730 asymptomatic WNV infections identified during screening of blood and organ donors. Of these, 4,073 (59.0%) were reported as West Nile neuroinvasive disease. California's WNV disease burden comprised 15% of all cases that were reported to the U.S. Centers for Disease Control and Prevention during this time, more than any other state. Additionally, 1,299 equine WNV cases were identified, along with detections of WNV in 23,322 dead birds, 31,695 mosquito pools, and 7,340 sentinel chickens. Annual enzootic detection of WNV typically preceded detection in humans and prompted enhanced intervention to reduce the risk of WNV transmission. Peak WNV activity occurred from July through October in the Central Valley and southern California. Less than five percent of WNV activity occurred in other regions of the state or outside of this time. WNV continues to be a major threat to public and wild avian health in California, particularly in southern California and the Central Valley during summer and early fall months. Local and state public health partners must continue statewide human and mosquito surveillance and facilitate effective mosquito control and bite prevention measures.
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Affiliation(s)
- Robert E. Snyder
- California Department of Public Health, Vector-Borne Disease Section, Richmond and Sacramento, California, United States of America
| | - Tina Feiszli
- California Department of Public Health, Vector-Borne Disease Section, Richmond and Sacramento, California, United States of America
| | - Leslie Foss
- California Department of Public Health, Vector-Borne Disease Section, Richmond and Sacramento, California, United States of America
| | - Sharon Messenger
- California Department of Public Health, Division of Communicable Disease Control, Richmond, California, United States of America
| | - Ying Fang
- Department of Pathology, Microbiology & Immunology, School of Veterinary Medicine, University of California, Davis, California, United States of America
| | - Christopher M. Barker
- Department of Pathology, Microbiology & Immunology, School of Veterinary Medicine, University of California, Davis, California, United States of America
| | - William K. Reisen
- Department of Pathology, Microbiology & Immunology, School of Veterinary Medicine, University of California, Davis, California, United States of America
| | - Duc J. Vugia
- California Department of Public Health, Division of Communicable Disease Control, Richmond, California, United States of America
| | - Kerry A. Padgett
- California Department of Public Health, Vector-Borne Disease Section, Richmond and Sacramento, California, United States of America
| | - Vicki L. Kramer
- California Department of Public Health, Vector-Borne Disease Section, Richmond and Sacramento, California, United States of America
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Duggal NK, Langwig KE, Ebel GD, Brault AC. On the Fly: Interactions Between Birds, Mosquitoes, and Environment That Have Molded West Nile Virus Genomic Structure Over Two Decades. JOURNAL OF MEDICAL ENTOMOLOGY 2019; 56:1467-1474. [PMID: 31549720 PMCID: PMC7182917 DOI: 10.1093/jme/tjz112] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/13/2019] [Indexed: 05/15/2023]
Abstract
West Nile virus (WNV) was first identified in North America almost 20 yr ago. In that time, WNV has crossed the continent and established enzootic transmission cycles, resulting in intermittent outbreaks of human disease that have largely been linked with climatic variables and waning avian seroprevalence. During the transcontinental dissemination of WNV, the original genotype has been displaced by two principal extant genotypes which contain an envelope mutation that has been associated with enhanced vector competence by Culex pipiens L. (Diptera: Culicidae) and Culex tarsalis Coquillett vectors. Analyses of retrospective avian host competence data generated using the founding NY99 genotype strain have demonstrated a steady reduction in viremias of house sparrows over time. Reciprocally, the current genotype strains WN02 and SW03 have demonstrated an inverse correlation between house sparrow viremia magnitude and the time since isolation. These data collectively indicate that WNV has evolved for increased avian viremia while house sparrows have evolved resistance to the virus such that the relative host competence has remained constant. Intrahost analyses of WNV evolution demonstrate that selection pressures are avian species-specific and purifying selection is greater in individual birds compared with individual mosquitoes, suggesting that the avian adaptive and/or innate immune response may impose a selection pressure on WNV. Phylogenomic, experimental evolutionary systems, and models that link viral evolution with climate, host, and vector competence studies will be needed to identify the relative effect of different selective and stochastic mechanisms on viral phenotypes and the capacity of newly evolved WNV genotypes for transmission in continuously changing landscapes.
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Affiliation(s)
- Nisha K Duggal
- Department of Biomedical Sciences and Pathobiology, Virginia Polytechnic Institute and State University, Blacksburg, VA
| | - Kate E Langwig
- Department of Biological Sciences, Virginia Polytechnic Institute and State University, Blacksburg, VA
| | - Gregory D Ebel
- Department of Microbiology, Immunology, and Pathology, Colorado State University, Fort Collins, CO
| | - Aaron C Brault
- Division of Vector-borne Diseases, Centers for Disease Control and Prevention, Fort Collins, CO
- Corresponding author, e-mail:
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Hadfield J, Brito AF, Swetnam DM, Vogels CBF, Tokarz RE, Andersen KG, Smith RC, Bedford T, Grubaugh ND. Twenty years of West Nile virus spread and evolution in the Americas visualized by Nextstrain. PLoS Pathog 2019; 15:e1008042. [PMID: 31671157 PMCID: PMC6822705 DOI: 10.1371/journal.ppat.1008042] [Citation(s) in RCA: 69] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
It has been 20 years since West Nile virus first emerged in the Americas, and since then, little progress has been made to control outbreaks caused by this virus. After its first detection in New York in 1999, West Nile virus quickly spread across the continent, causing an epidemic of human disease and massive bird die-offs. Now the virus has become endemic to the United States, where an estimated 7 million human infections have occurred, making it the leading mosquito-borne virus infection and the most common cause of viral encephalitis in the country. To bring new attention to one of the most important mosquito-borne viruses in the Americas, we provide an interactive review using Nextstrain: a visualization tool for real-time tracking of pathogen evolution (nextstrain.org/WNV/NA). Nextstrain utilizes a growing database of more than 2,000 West Nile virus genomes and harnesses the power of phylogenetics for students, educators, public health workers, and researchers to visualize key aspects of virus spread and evolution. Using Nextstrain, we use virus genomics to investigate the emergence of West Nile virus in the U S, followed by its rapid spread, evolution in a new environment, establishment of endemic transmission, and subsequent international spread. For each figure, we include a link to Nextstrain to allow the readers to directly interact with and explore the underlying data in new ways. We also provide a brief online narrative that parallels this review to further explain the data and highlight key epidemiological and evolutionary features (nextstrain.org/narratives/twenty-years-of-WNV). Mirroring the dynamic nature of outbreaks, the Nextstrain links provided within this paper are constantly updated as new West Nile virus genomes are shared publicly, helping to stay current with the research. Overall, our review showcases how genomics can track West Nile virus spread and evolution, as well as potentially uncover novel targeted control measures to help alleviate its public health burden.
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Affiliation(s)
- James Hadfield
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America
| | - Anderson F. Brito
- Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, Connecticut, United States of America
| | - Daniele M. Swetnam
- Department of Pathology, Microbiology and Immunology, University of California, Davis, Davis, California, United States of America
| | - Chantal B. F. Vogels
- Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, Connecticut, United States of America
| | - Ryan E. Tokarz
- Department of Entomology, Iowa State University, Ames, Iowa, United States of America
| | - Kristian G. Andersen
- Department of Immunology and Microbiology, Scripps Research, La Jolla, California, United States of America
- Scripps Research Translational Institute, La Jolla, California, United States of America
| | - Ryan C. Smith
- Department of Entomology, Iowa State University, Ames, Iowa, United States of America
| | - Trevor Bedford
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America
| | - Nathan D. Grubaugh
- Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, Connecticut, United States of America
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Therrien C, Fournier É, Ludwig A, Ménard J, Charest H, Martineau C. Phylogenetic analysis of West Nile virus in Quebec, Canada, 2004-2016: Co-circulation of distinct variants harbouring conserved amino acid motifs in North America. Virology 2019; 537:65-73. [PMID: 31465892 DOI: 10.1016/j.virol.2019.08.019] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2019] [Revised: 08/16/2019] [Accepted: 08/19/2019] [Indexed: 11/18/2022]
Abstract
West Nile virus (WNV) was introduced for the first time in the western hemisphere in 1999 in New York City. In 2002, a phenotype-modifying mutation (Env-V159A) defined the first North American genotype WN02. So far, three genotypes has been described in North America but little is known about WNV evolution in Canada. We report the phylogenetic characterization of twenty-six WNV genomes isolated from mosquitoes in the province of Quebec. WNV strains found in Quebec are phylogenetically related to American strains collected in northern and southern regions. We also noted the presence of two robust monophyletic groups of isolates characterized by distinct conserved amino acid motifs. These emerging genotypes were detected for several years in different ecosystems. These results highlight the need for the maintenance of a nationwide surveillance to follow the dispersion of emergent WNV genotypes.
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Affiliation(s)
- Christian Therrien
- Laboratoire de santé publique du Québec, Institut national de santé publique du Québec. 20045 Chemin Sainte-Marie, Saint-Anne-de-Bellevue, H9X 3Y3, QC, Canada.
| | - Éric Fournier
- Laboratoire de santé publique du Québec, Institut national de santé publique du Québec. 20045 Chemin Sainte-Marie, Saint-Anne-de-Bellevue, H9X 3Y3, QC, Canada
| | - Antoinette Ludwig
- Laboratoire National de microbiologie, Agence de santé publique du Canada, 3200 Sicotte, Saint-Hyacinthe, QC, J2S 2M2, Canada
| | - Joel Ménard
- Laboratoire de santé publique du Québec, Institut national de santé publique du Québec. 20045 Chemin Sainte-Marie, Saint-Anne-de-Bellevue, H9X 3Y3, QC, Canada
| | - Hugues Charest
- Laboratoire de santé publique du Québec, Institut national de santé publique du Québec. 20045 Chemin Sainte-Marie, Saint-Anne-de-Bellevue, H9X 3Y3, QC, Canada
| | - Christine Martineau
- Laboratoire de santé publique du Québec, Institut national de santé publique du Québec. 20045 Chemin Sainte-Marie, Saint-Anne-de-Bellevue, H9X 3Y3, QC, Canada
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Abstract
West Nile virus (WNV) emerged in the Americas with its introduction in 1999 and now is considered endemic across the continent. In 2002, WNV was detected in Mexico, where its occurrence and mortality are considerably lower compared with the US. However, continuous national surveillance programs in Mexico are nonexistent. Birds are considered the primary hosts and primary geographic dispersers of this pathogen. A total of 200 cloacal and tracheal samples from wild migratory or resident birds were retrospectively analyzed using reverse transcription PCR to detect WNV from birds collected in Mexico from 2008 to 2009. The overall prevalence was 8% (16/200), and positive samples were from Oaxaca, Chiapas, and Tamaulipas in Ruby-throated Hummingbird ( Archilochus colubris), Double-crested Cormorant ( Phalacrocorax auritus), Ring-billed Gull ( Larus delawarensis), and Mourning Dove ( Zenaida macroura). Analysis of the partial sequence of the envelope gene from one of the samples from Oaxaca provided evidence that the virus belonged to the WN99 genotype. Taken together, these results demonstrated that WNV circulated in wild birds from northern and southern Mexico during the 2008-09 season, providing further information about the presence of WNV in Mexico.
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Abstract
Although long recognized as a human pathogen, West Nile virus (WNV) emerged as a significant public health problem following its introduction and spread across North America. Subsequent years have seen a greater understanding of all aspects of this viral infection. The North American epidemic resulted in a further understanding of the virology, pathogenesis, clinical features, and epidemiology of WNV infection. Approximately 80% of human WNV infections are asymptomatic. Most symptomatic people experience an acute systemic febrile illness; less than 1% of infected people develop neuroinvasive disease, which typically manifests as meningitis, encephalitis, or anterior myelitis resulting in acute flaccid paralysis. Older age is associated with more severe illness and higher mortality; other risk factors for poor outcome have been challenging to identify. In addition to natural infection through mosquito bites, transfusion- and organ transplant-associated infections have occurred. Since there is no definitive treatment for WNV infection, protection from mosquito bites and other preventative measures are critical. WNV has reached an endemic pattern in North America, but the future epidemiologic pattern is uncertain.
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Kain MP, Bolker BM. Can existing data on West Nile virus infection in birds and mosquitos explain strain replacement? Ecosphere 2017. [DOI: 10.1002/ecs2.1684] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Affiliation(s)
- Morgan P. Kain
- Department of Biology; McMaster University; 1280 Main Street West Hamilton Ontario L8S 4K1 Canada
| | - Benjamin M. Bolker
- Department of Biology; McMaster University; 1280 Main Street West Hamilton Ontario L8S 4K1 Canada
- Department of Mathematics and Statistics; McMaster University; 1280 Main Street West Hamilton Ontario L8S 4L8 Canada
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11
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Dynamics of West Nile virus evolution in mosquito vectors. Curr Opin Virol 2016; 21:132-138. [PMID: 27788400 DOI: 10.1016/j.coviro.2016.09.007] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2016] [Revised: 09/09/2016] [Accepted: 09/12/2016] [Indexed: 01/24/2023]
Abstract
West Nile virus remains the most common cause of arboviral encephalitis in North America. Since it was introduced, it has undergone adaptive genetic change as it spread throughout the continent. The WNV transmission cycle is relatively tractable in the laboratory. Thus the virus serves as a convenient model system for studying the population biology of mosquito-borne flaviviruses as they undergo transmission to and from mosquitoes and vertebrates. This review summarizes the current knowledge regarding the population dynamics of this virus within mosquito vectors.
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Plante JA, Torres M, Huang CYH, Beasley DWC. Plasticity of a critical antigenic determinant in the West Nile virus NY99 envelope protein domain III. Virology 2016; 496:97-105. [PMID: 27284640 DOI: 10.1016/j.virol.2016.05.024] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2016] [Revised: 05/27/2016] [Accepted: 05/28/2016] [Indexed: 01/23/2023]
Abstract
West Nile virus (WNV) is a mosquito-borne flavivirus that causes febrile illness, encephalitis, and occasionally death in humans. The envelope protein is the main component of the WNV virion surface, and domain III of the envelope protein (EIII) is both a putative receptor binding domain and a target of highly specific, potently neutralizing antibodies. Envelope E-332 (E-332) is known to have naturally occurring variation and to be a key determinant of neutralization for anti-EIII antibodies. A panel of viruses containing all possible amino acid substitutions at E-332 was constructed. E-332 was found to be highly tolerant of mutation, and almost all of these changes had large impacts on antigenicity of EIII but only limited effects on growth or virulence phenotypes.
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Affiliation(s)
- Jessica A Plante
- Department of Pathology, University of Texas Medical Branch, Galveston, TX 77555, USA; Sealy Center for Vaccine Development, University of Texas Medical Branch, Galveston, TX 77555, USA.
| | - Maricela Torres
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, TX 77555, USA
| | - Claire Y-H Huang
- Arbovirus Diseases Branch, Division of Vector-Borne Diseases, Centers for Disease Control and Prevention, Fort Collins, CO 80521, USA
| | - David W C Beasley
- Sealy Center for Vaccine Development, University of Texas Medical Branch, Galveston, TX 77555, USA; Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, TX 77555, USA; Institute for Human Infections and Immunity, University of Texas Medical Branch, Galveston, TX 77555, USA.
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13
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Genetic Variability of West Nile Virus in U.S. Blood Donors from the 2012 Epidemic Season. PLoS Negl Trop Dis 2016; 10:e0004717. [PMID: 27182734 PMCID: PMC4868353 DOI: 10.1371/journal.pntd.0004717] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2015] [Accepted: 04/27/2016] [Indexed: 12/26/2022] Open
Abstract
West Nile virus (WNV) is an arbovirus maintained in nature in a bird-mosquito enzootic cycle which can also infect other vertebrates including humans. WNV is now endemic in the United States (U.S.), causing yearly outbreaks that have resulted in an estimated total of 4-5 million human infections. Over 41,700 cases of West Nile disease, including 18,810 neuroinvasive cases and 1,765 deaths, were reported to the CDC between 1999 and 2014. In 2012, the second largest West Nile outbreak in the U.S. was reported, which caused 5,674 cases and 286 deaths. WNV continues to evolve, and three major WNV lineage I genotypes (NY99, WN02, and SW/WN03) have been described in the U.S. since introduction of the virus in 1999. We report here the WNV sequences obtained from 19 human samples acquired during the 2012 U.S. outbreak and our examination of the evolutionary dynamics in WNV isolates sequenced from 1999-2012. Maximum-likelihood and Bayesian methods were used to perform the phylogenetic analyses. Selection pressure analyses were performed with the HyPhy package using the Datamonkey web-server. Using different codon-based and branch-site selection models, we detected a number of codons subjected to positive pressure in WNV genes. Thirteen of the 19 completely sequenced isolates from 10 U.S. states were genetically similar, sharing up to 55 nucleotide mutations and 4 amino acid substitutions when compared with the prototype isolate WN-NY99. Overall, these analyses showed that following a brief contraction in 2008-2009, WNV genetic divergence in the U.S. continued to increase in 2012, and that closely related variants were found across a broad geographic range of the U.S., coincident with the second-largest WNV outbreak in U.S.
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Caraballo EV, Hunsperger E, Martínez I. Characterization of Puerto Rican West Nile Virus isolates in mice. Virol J 2015; 12:137. [PMID: 26357867 PMCID: PMC4566862 DOI: 10.1186/s12985-015-0363-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2014] [Accepted: 08/18/2015] [Indexed: 02/01/2023] Open
Abstract
BACKGROUND West Nile virus (WNV) is a neurotropic arbovirus that was first isolated in 1937 in the West Nile District of Uganda. The virus emerged in New York in 1999 and is now endemic in North America (2007). The first virus isolates from Puerto Rico were obtained in 2007 from a chicken (PR20wh) and a mosquito pool (PR423). Our study further characterized these viral isolates using in vitro plaque morphology assays and in vivo using a Balb/c mice pathogenesis model. METHODS AND RESULTS In the in vitro experiments, PR WNV isolates produced significantly smaller plaques in Vero cells compared to the New York 1999 strain (NY99). For the in vivo experiments, PR WNV isolates were propagated in mammalian (Vero) and insect (C6/36) cell lines and then inoculated in Balb/c mice. When WNV was propagated in Vero cells, we observed a trend towards significance in the survival rate with PR20wh compared to NY99 (log rank, p = 0.092). Regardless of whether the viral isolates were propagated in Vero or C6/36 cells, we found a significantly greater survival in mice infected with PR20wh strain, when compared to NY99 (log rank, p = 0.04), while no statistical difference was detected between PR423 and NY99 (p = 0.84). The average survival time (AST) in mice was significantly lower in C6/36-derived PR423 when compared to C6/36-derived NY99 (t-test, p = 0.013), and Vero-derived PR423 (t-test, p < 0.001). Eight days post infection in mice the viral load in brain tissue for Vero-derived PR423 was significantly higher when compared to NY99 and PR20wh. CONCLUSIONS These results suggest that the PR WNV isolate, PR20wh, is a less pathogenic strain in mice than NY99. Moreover, we found that PR423 is a pathogenic isolate that causes faster mortality than NY99, when propagated in C6/36.
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Affiliation(s)
- Elba V Caraballo
- Department of Microbiology and Medical Zoology, University of Puerto Rico, Room A-355 UPR-Medical Sciences Campus, PO Box 365067, San Juan, 00936-5067, Puerto Rico.
| | - Elizabeth Hunsperger
- Centers for Disease Control, Division of Vector Borne Diseases, Dengue Branch San Juan, San Juan, Puerto Rico.
| | - Idalí Martínez
- Department of Microbiology and Medical Zoology, University of Puerto Rico, Room A-355 UPR-Medical Sciences Campus, PO Box 365067, San Juan, 00936-5067, Puerto Rico.
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López RH, Soto SU, Gallego-Gómez JC. Evolutionary relationships of West Nile virus detected in mosquitoes from a migratory bird zone of Colombian Caribbean. Virol J 2015; 12:80. [PMID: 25989901 PMCID: PMC4445300 DOI: 10.1186/s12985-015-0310-8] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2015] [Accepted: 05/13/2015] [Indexed: 11/10/2022] Open
Abstract
Background West Nile virus (WNV) is a member of the genus Flavivirus, and it is transmitted between Culex sp. mosquitoes and avian hosts. Equids and humans are commonly infected with WNV as dead-end hosts, and the signs and symptoms of infection range from mild illness to neurologic symptoms as encephalitis, meningitis and sometimes death. Previous phylogenetic studies have classified WNV into six genetically distinct lineages and provided valuable insight on WNV dispersal patterns within the Americas and its emergence in different geographic areas. In this study, we isolated, sequenced and genetically characterized the NS5 and envelope genes for two WNV strains detected from Northern of Colombia. Herein we describe the evolutionary relationships with representative WNV-strains isolated in a variety of epidemic outbreaks and countries, to define the phylogeographic origin and possible implications in the epidemiology of this emergent virus in Colombia. Findings Fragments of the NS5 and Envelope genes were amplified with RT-PCR and sequenced to obtain 1186-nt and 1504-nt portions, respectively. Our sequences were aligned with 46 sequences from WNV-strains collected in the U.S., Mexico and Argentina for phylogenetic reconstruction using Bayesian methods. Sequence analyses identified unique non-synonymous substitutions in the envelope gene of the WNV strains we detected, and our sequences clustered together with those from the attenuated Texas – 2002 genotype. Conclusions A new strain closely related to attenuated strains collected in Texas during 2002 was identified from Colombia by phylogenetic analysis. This finding may explain the absence of human/equine cases of WNV-encephalitis or severe disease in Colombia and possibly other regions of South America. Follow-up studies are needed in ecosystems used by migratory birds areas and virological/entomological surveillance.
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Affiliation(s)
- Richard Hoyos López
- Molecular and Translational Medicine Group, Medical Research Institute, Faculty of Medicina, Universidad de Antioquia, Medellín, Colombia. .,Molecular Systematics Research Group, Biosciences School - Sciences Faculty, Universidad Nacional de Colombia, Medellín, Colombia.
| | - Sandra Uribe Soto
- Molecular Systematics Research Group, Biosciences School - Sciences Faculty, Universidad Nacional de Colombia, Medellín, Colombia.
| | - Juan Carlos Gallego-Gómez
- Molecular and Translational Medicine Group, Medical Research Institute, Faculty of Medicina, Universidad de Antioquia, Medellín, Colombia.
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Brault AC, Fang Y, Reisen WK. Multiplex qRT-PCR for the Detection of Western Equine Encephalomyelitis, St. Louis Encephalitis, and West Nile Viral RNA in Mosquito Pools (Diptera: Culicidae). JOURNAL OF MEDICAL ENTOMOLOGY 2015; 52:491-9. [PMID: 26334826 PMCID: PMC4581483 DOI: 10.1093/jme/tjv021] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/21/2014] [Accepted: 01/26/2015] [Indexed: 05/15/2023]
Abstract
Following the introduction of West Nile virus into California during the summer of 2003, public health and vector control programs expanded surveillance efforts and were in need of diagnostics capable of rapid, sensitive, and specific detection of arbovirus infections of mosquitoes to inform decision support for intervention. Development of a multiplex TaqMan or real-time semiquantitative reverse transcription polymerase chain reaction (RT-PCR) assay in which three virus specific primer-probe sets were used in the same reaction is described herein for the detection of western equine encephalomyelitis, St. Louis encephalitis and West Nile viral RNA. Laboratory validation and field data from 10 transmission seasons are reported. The comparative sensitivity and specificity of this multiplex assay to singleplex RT-PCR as well as an antigen detection (rapid analyte measurement platform) and standard plaque assays indicate this assay to be rapid and useful in providing mosquito infection data to estimate outbreak risk.
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Affiliation(s)
- Aaron C Brault
- Center for Vectorborne Diseases and Department of Pathology, Microbiology and Immunology, School of Veterinary Medicine, University of California, Davis, CA 95616. Division of Vector-Borne Diseases, Centers for Diseases Control and Prevention, Fort Collins, CO 80512
| | - Ying Fang
- Center for Vectorborne Diseases and Department of Pathology, Microbiology and Immunology, School of Veterinary Medicine, University of California, Davis, CA 95616
| | - William K Reisen
- Center for Vectorborne Diseases and Department of Pathology, Microbiology and Immunology, School of Veterinary Medicine, University of California, Davis, CA 95616.
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Huang YJS, Higgs S, Horne KM, Vanlandingham DL. Flavivirus-mosquito interactions. Viruses 2014; 6:4703-30. [PMID: 25421894 PMCID: PMC4246245 DOI: 10.3390/v6114703] [Citation(s) in RCA: 104] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2014] [Revised: 11/17/2014] [Accepted: 11/20/2014] [Indexed: 12/20/2022] Open
Abstract
The Flavivirus genus is in the family Flaviviridae and is comprised of more than 70 viruses. These viruses have a broad geographic range, circulating on every continent except Antarctica. Mosquito-borne flaviviruses, such as yellow fever virus, dengue virus serotypes 1-4, Japanese encephalitis virus, and West Nile virus are responsible for significant human morbidity and mortality in affected regions. This review focuses on what is known about flavivirus-mosquito interactions and presents key data collected from the field and laboratory-based molecular and ultrastructural evaluations.
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Affiliation(s)
- Yan-Jang S Huang
- Department of Diagnostic Medicine and Pathobiology, College of Veterinary Medicine, Kansas State University, Manhattan, KS 66506, USA.
| | - Stephen Higgs
- Department of Diagnostic Medicine and Pathobiology, College of Veterinary Medicine, Kansas State University, Manhattan, KS 66506, USA.
| | - Kate McElroy Horne
- Biosecurity Research Institute, Kansas State University, Manhattan, KS 66506, USA.
| | - Dana L Vanlandingham
- Department of Diagnostic Medicine and Pathobiology, College of Veterinary Medicine, Kansas State University, Manhattan, KS 66506, USA.
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Plante JA, Burkhalter KL, Mann BR, Godsey MS, Mutebi JP, Beasley DWC. Co-circulation of West Nile virus variants, Arizona, USA, 2010. Emerg Infect Dis 2014; 20:272-5. [PMID: 24447818 PMCID: PMC3901498 DOI: 10.3201/eid2002.131008] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Molecular analysis of West Nile virus (WNV) isolates obtained during a 2010 outbreak in Maricopa County, Arizona, USA, demonstrated co-circulation of 3 distinct genetic variants, including strains with novel envelope protein mutations. These results highlight the continuing evolution of WNV in North America and the current complexity of WNV dispersal and transmission.
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Evolutionary dynamics of West Nile virus in Georgia, 2001-2011. Virus Genes 2014; 49:132-6. [PMID: 24691819 DOI: 10.1007/s11262-014-1061-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2013] [Accepted: 03/10/2014] [Indexed: 10/25/2022]
Abstract
From 1999-2001, West Nile virus (WNV) spread throughout the eastern United States (US) and was first detected in Georgia in 2001. To date, the virus has been detected in over 2,500 dead wild bird and mosquito samples from across Georgia. We sequenced the premembrane (preM) and envelope gene (E) (2004 bp) from 111 isolates collected from 2001 to 2011. To assess viral gene flow from other geographic regions in the US, we combined our data with WNV sequences available at the National Center for Biotechnology Information (NCBI) and performed phylogenetic analysis. We found evidence that WNV isolates detected in Chatham County Georgia most likely originated from the Northeastern United States. These results highlight the growing importance of adequate genetic surveillance for monitoring and controlling viruses of public health concern.
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Kolekar P, Hake N, Kale M, Kulkarni-Kale U. WNV Typer: a server for genotyping of West Nile viruses using an alignment-free method based on a return time distribution. J Virol Methods 2014; 198:41-55. [PMID: 24388930 DOI: 10.1016/j.jviromet.2013.12.012] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2013] [Revised: 11/27/2013] [Accepted: 12/17/2013] [Indexed: 01/20/2023]
Abstract
West Nile virus (WNV), genus Flavivirus, family Flaviviridae, is a major cause of viral encephalitis with broad host range and global spread. The virus has undergone a series of evolutionary changes with emergence of various genotypic lineages that are known to differ in type and severity of the diseases caused. Currently, genotyping is carried out using molecular phylogeny of complete coding sequences and genotype is assigned based on proximity to reference genotypes in tree topology. Efficient epidemiological surveillance of WNVs demands development of objective criteria for typing. An alignment-free approach based on return time distribution (RTD) of k-mers has been validated for genotyping of WNVs. The RTDs of complete genome sequences at k=7 were found to be optimum for classification of the known lineages of WNVs as well as for genotyping. It provides time and computationally efficient alternative for genome based annotation of WNV lineages. The development of a WNV Typer server based on RTD is described (http://bioinfo.net.in/wnv/homepage.html). Both the method and the server have 100% sensitivity and specificity.
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Affiliation(s)
| | - Nilesh Hake
- Bioinformatics Centre, University of Pune, Pune 411007, India
| | - Mohan Kale
- Department of Statistics, University of Pune, Pune 411007, India.
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Marka A, Diamantidis A, Papa A, Valiakos G, Chaintoutis SC, Doukas D, Tserkezou P, Giannakopoulos A, Papaspyropoulos K, Patsoula E, Badieritakis E, Baka A, Tseroni M, Pervanidou D, Papadopoulos NT, Koliopoulos G, Tontis D, Dovas CI, Billinis C, Tsakris A, Kremastinou J, Hadjichristodoulou C. West Nile virus state of the art report of MALWEST Project. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2013; 10:6534-610. [PMID: 24317379 PMCID: PMC3881129 DOI: 10.3390/ijerph10126534] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/30/2013] [Revised: 11/11/2013] [Accepted: 11/12/2013] [Indexed: 11/16/2022]
Abstract
During the last three years Greece is experiencing the emergence of West Nile virus (WNV) epidemics. Within this framework, an integrated surveillance and control programme (MALWEST project) with thirteen associate partners was launched aiming to investigate the disease and suggest appropriate interventions. One out of seven work packages of the project is dedicated to the State of the Art report for WNV. Three expert working groups on humans, animals and mosquitoes were established. Medical databases (PubMed, Scopus) were searched together with websites: e.g., WHO, CDC, ECDC. In total, 1,092 relevant articles were initially identified and 258 of them were finally included as references regarding the current knowledge about WNV, along with 36 additional sources (conference papers, reports, book chapters). The review is divided in three sections according to the fields of interest: (1) WNV in humans (epidemiology, molecular characteristics, transmission, diagnosis, treatment, prevention, surveillance); (2) WNV in animals (epidemiological and transmission characteristics concerning birds, horses, reptiles and other animal species) and (3) WNV in mosquitoes (control, surveillance). Finally, some examples of integrated surveillance programmes are presented. The introduction and establishment of the disease in Greece and other European countries further emphasizes the need for thorough research and broadening of our knowledge on this viral pathogen.
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Affiliation(s)
- Andriani Marka
- Department of Microbiology, Faculty of Medicine, University of Athens, Athens 11527, Greece; E-mail:
| | - Alexandros Diamantidis
- Laboratory of Entomology and Agricultural Zoology, School of Agricultural Sciences, University of Thessaly, Volos 38446, Greece; E-mails: (A.D.); (N.T.P.)
| | - Anna Papa
- National Reference Center for Arboviruses, Department of Microbiology, School of Medicine, Aristotle University of Thessaloniki, Thessaloniki 54124, Greece; E-mail:
| | - George Valiakos
- Laboratory of Microbiology and Parasitology, Faculty of Veterinary Medicine, University of Thessaly, Karditsa 43100, Greece; E-mails: (G.V); (A.G.); (K.P.); (C.B.)
| | - Serafeim C. Chaintoutis
- Laboratory of Microbiology and Infectious Diseases, School of Veterinary Medicine, Faculty of Health Sciences, Aristotle University of Thessaloniki, Thessaloniki 54124, Greece; E-mails: (S.C.C.); (C.I.D.)
| | - Dimitrios Doukas
- Laboratory of Pathology, Faculty of Veterinary Medicine, University of Thessaly, Karditsa 43100, Greece; E-mails: (D.D.); (D.T.)
| | - Persefoni Tserkezou
- Department of Microbiology, Faculty of Medicine, University of Athens, Athens 11527, Greece; E-mail:
| | - Alexios Giannakopoulos
- Laboratory of Microbiology and Parasitology, Faculty of Veterinary Medicine, University of Thessaly, Karditsa 43100, Greece; E-mails: (G.V); (A.G.); (K.P.); (C.B.)
| | - Konstantinos Papaspyropoulos
- Laboratory of Microbiology and Parasitology, Faculty of Veterinary Medicine, University of Thessaly, Karditsa 43100, Greece; E-mails: (G.V); (A.G.); (K.P.); (C.B.)
| | - Eleni Patsoula
- Department of Parasitology, Entomology and Tropical Diseases, National School of Public Health, Athens 11521, Greece; E-mail:
| | - Evangelos Badieritakis
- Laboratory of Biological Control of Pesticides, Benaki Phytopathological Institute, Athens 14561, Greece; E-mails: (E.B.); (G.K.)
| | - Agoritsa Baka
- Hellenic Centre for Disease Control and Prevention (KEELPNO), Athens 15123, Greece; E-mails: (A.B.); (M.T.); (D.P.); (J.K.)
| | - Maria Tseroni
- Hellenic Centre for Disease Control and Prevention (KEELPNO), Athens 15123, Greece; E-mails: (A.B.); (M.T.); (D.P.); (J.K.)
| | - Danai Pervanidou
- Hellenic Centre for Disease Control and Prevention (KEELPNO), Athens 15123, Greece; E-mails: (A.B.); (M.T.); (D.P.); (J.K.)
| | - Nikos T. Papadopoulos
- Laboratory of Entomology and Agricultural Zoology, School of Agricultural Sciences, University of Thessaly, Volos 38446, Greece; E-mails: (A.D.); (N.T.P.)
| | - George Koliopoulos
- Laboratory of Biological Control of Pesticides, Benaki Phytopathological Institute, Athens 14561, Greece; E-mails: (E.B.); (G.K.)
| | - Dimitrios Tontis
- Laboratory of Pathology, Faculty of Veterinary Medicine, University of Thessaly, Karditsa 43100, Greece; E-mails: (D.D.); (D.T.)
| | - Chrysostomos I. Dovas
- Laboratory of Microbiology and Infectious Diseases, School of Veterinary Medicine, Faculty of Health Sciences, Aristotle University of Thessaloniki, Thessaloniki 54124, Greece; E-mails: (S.C.C.); (C.I.D.)
| | - Charalambos Billinis
- Laboratory of Microbiology and Parasitology, Faculty of Veterinary Medicine, University of Thessaly, Karditsa 43100, Greece; E-mails: (G.V); (A.G.); (K.P.); (C.B.)
| | - Athanassios Tsakris
- Author to whom correspondence should be addressed; E-Mail: ; Tel.: +30-2410-565-007; Fax: +30-2410-565-051
| | - Jenny Kremastinou
- Hellenic Centre for Disease Control and Prevention (KEELPNO), Athens 15123, Greece; E-mails: (A.B.); (M.T.); (D.P.); (J.K.)
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Molecular epidemiology and evolution of West Nile virus in North America. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2013; 10:5111-29. [PMID: 24135819 PMCID: PMC3823310 DOI: 10.3390/ijerph10105111] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/05/2013] [Revised: 10/05/2013] [Accepted: 10/08/2013] [Indexed: 12/17/2022]
Abstract
West Nile virus (WNV) was introduced to New York in 1999 and rapidly spread throughout North America and into parts of Central and South America. Displacement of the original New York (NY99) genotype by the North America/West Nile 2002 (NA/WN02) genotype occurred in 2002 with subsequent identification of a novel genotype in 2003 in isolates collected from the southwestern Unites States region (SW/WN03 genotype). Both genotypes co-circulate to date. Subsequent WNV surveillance studies have confirmed additional genotypes in the United States that have become extinct due to lack of a selective advantage or stochastic effect; however, the dynamic emergence, displacement, and extinction of multiple WNV genotypes in the US from 1999–2012 indicates the continued evolution of WNV in North America.
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Genetic analysis of West Nile virus isolates from an outbreak in Idaho, United States, 2006-2007. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2013; 10:4486-506. [PMID: 24065039 PMCID: PMC3799518 DOI: 10.3390/ijerph10094486] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/09/2013] [Revised: 09/12/2013] [Accepted: 09/16/2013] [Indexed: 12/26/2022]
Abstract
West Nile virus (WNV) appeared in the U.S. in 1999 and has since become endemic, with yearly summer epidemics causing tens of thousands of cases of serious disease over the past 14 years. Analysis of WNV strains isolated during the 2006–2007 epidemic seasons demonstrates that a new genetic variant had emerged coincidentally with an intense outbreak in Idaho during 2006. The isolates belonging to the new variant carry a 13 nt deletion, termed ID-Δ13, located at the variable region of the 3′UTR, and are genetically related. The analysis of deletions and insertions in the 3′UTR of two major lineages of WNV revealed the presence of conserved repeats and two indel motifs in the variable region of the 3′UTR. One human and two bird isolates from the Idaho 2006–2007 outbreaks were sequenced using Illumina technology and within-host variability was analyzed. Continued monitoring of new genetic variants is important for public health as WNV continues to evolve.
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Abstract
The introduction, dispersal and establishment of West Nile virus in North America were reviewed, focusing on factors that may have enhanced receptivity and enabled the invasion process. The overwintering persistence of this tropical virus within temperate latitudes was unexpected, but was key in the transition from invasion to endemic establishment. The cascade of temporal events allowing sporadic amplification to outbreak levels was discussed within a future perspective.
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Añez G, Grinev A, Chancey C, Ball C, Akolkar N, Land KJ, Winkelman V, Stramer SL, Kramer LD, Rios M. Evolutionary dynamics of West Nile virus in the United States, 1999-2011: phylogeny, selection pressure and evolutionary time-scale analysis. PLoS Negl Trop Dis 2013; 7:e2245. [PMID: 23738027 PMCID: PMC3667762 DOI: 10.1371/journal.pntd.0002245] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2012] [Accepted: 04/17/2013] [Indexed: 01/28/2023] Open
Abstract
West Nile virus (WNV), an arbovirus maintained in a bird-mosquito enzootic cycle, can infect other vertebrates including humans. WNV was first reported in the US in 1999 where, to date, three genotypes belonging to WNV lineage I have been described (NY99, WN02, SW/WN03). We report here the WNV sequences obtained from two birds, one mosquito, and 29 selected human samples acquired during the US epidemics from 2006–2011 and our examination of the evolutionary dynamics in the open-reading frame of WNV isolates reported from 1999–2011. Maximum-likelihood and Bayesian methods were used to perform the phylogenetic analyses and selection pressure analyses were conducted with the HyPhy package. Phylogenetic analysis identified human WNV isolates within the main WNV genotypes that have circulated in the US. Within genotype SW/WN03, we have identified a cluster with strains derived from blood donors and birds from Idaho and North Dakota collected during 2006–2007, termed here MW/WN06. Using different codon-based and branch-site selection models, we detected a number of codons subjected to positive pressure in WNV genes. The mean nucleotide substitution rate for WNV isolates obtained from humans was calculated to be 5.06×10−4 substitutions/site/year (s/s/y). The Bayesian skyline plot shows that after a period of high genetic variability following the introduction of WNV into the US, the WNV population appears to have reached genetic stability. The establishment of WNV in the US represents a unique opportunity to understand how an arbovirus adapts and evolves in a naïve environment. We describe a novel, well-supported cluster of WNV formed by strains collected from humans and birds from Idaho and North Dakota. Adequate genetic surveillance is essential to public health since new mutants could potentially affect viral pathogenesis, decrease performance of diagnostic assays, and negatively impact the efficacy of vaccines and the development of specific therapies. West Nile Virus (WNV) is a mosquito-borne virus of African origin that is widespread around the world. The WNV life-cycle involves mosquitoes and birds, but humans and other animals can be infected, although they are not considered to be important players in the transmission cycle. Clinically, most WNV infections are unapparent, but the virus can disseminate to the central nervous system causing a potentially fatal neurological disease, especially in susceptible populations including elderly and immunocompromised individuals. West Nile virus can also be transmitted by organ transplant and by transfusion of blood and blood components. Like other arboviruses, WNV has the extraordinary capacity of growing in the different microenvironments represented by the invertebrate vector and the vertebrate hosts. From an evolutionary standpoint, the arrival of WNV in the US in 1999 represents a unique opportunity to explore the processes involved in the adaptation and dissemination of an arbovirus in a naïve environment. From the study of WNV sequences, we can not only learn about the evolutionary mechanisms that govern arboviruses, but also update diagnostic tests that rely on the detection of the viral genome upon the occurrence of mutations and study the existence of genetic markers that may be responsible for increases in clinical cases and their severity.
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Affiliation(s)
- Germán Añez
- Laboratory of Emerging Pathogens, DETTD/OBRR/CBER, US Food and Drug Administration, Bethesda, Maryland, United States of America
- * E-mail: (GA); (AG); (MR)
| | - Andriyan Grinev
- Laboratory of Emerging Pathogens, DETTD/OBRR/CBER, US Food and Drug Administration, Bethesda, Maryland, United States of America
- * E-mail: (GA); (AG); (MR)
| | - Caren Chancey
- Laboratory of Emerging Pathogens, DETTD/OBRR/CBER, US Food and Drug Administration, Bethesda, Maryland, United States of America
| | - Christopher Ball
- Idaho Bureau of Laboratories, Boise, Idaho, United States of America
| | - Namita Akolkar
- Laboratory of Emerging Pathogens, DETTD/OBRR/CBER, US Food and Drug Administration, Bethesda, Maryland, United States of America
| | - Kevin J. Land
- Bonfils Blood Center, Denver, Colorado, United States of America
| | - Valerie Winkelman
- Creative Testing Solutions, Tempe, Arizona, United States of America
| | - Susan L. Stramer
- American Red Cross, Gaithersburg, Maryland, United States of America
| | - Laura D. Kramer
- New York State Department of Health, Albany, New York, United States of America, and School of Public Health, State University of New York at Albany, Albany, New York, United States of America
| | - Maria Rios
- Laboratory of Emerging Pathogens, DETTD/OBRR/CBER, US Food and Drug Administration, Bethesda, Maryland, United States of America
- * E-mail: (GA); (AG); (MR)
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Kesavaraju B, Farajollahi A, Lampman RL, Hutchinson M, Krasavin NM, Graves SE, Dickson SL. Evaluation of a rapid analyte measurement platform for West Nile virus detection based on United States mosquito control programs. Am J Trop Med Hyg 2012; 87:359-63. [PMID: 22855771 DOI: 10.4269/ajtmh.2012.11-0662] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
The rapid analyte measurement platform (RAMP) system is an immunoassay test for West Nile virus (WNV) detection. Although reverse transcriptase-polymerase chain reaction (RT-PCR) methodology has been regarded as the gold standard for confirming WNV presence, usage of RAMP testing kits has increased in the past years. We collected RAMP test result data that were subsequently confirmed with RT-PCR methodology from mosquito control agencies to evaluate the efficacy of the RAMP testing. Results indicate that there are a high number of false positives (RAMP positive, RT-PCR negative) with RAMP testing. Correlation between RAMP unit values and RT-PCR cycle threshold values were varied depending on the primer/probe being compared. Comparison of RT-PCR results (on the same samples) between laboratories also indicates variation among the procedures and their potential to influence the RAMP testing efficacies. We discuss the potential issues and solutions that could prevent the high rate of false positives.
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McMullen AR, Albayrak H, May FJ, Davis CT, Beasley DWC, Barrett ADT. Molecular evolution of lineage 2 West Nile virus. J Gen Virol 2012; 94:318-325. [PMID: 23136360 DOI: 10.1099/vir.0.046888-0] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Since the 1990s West Nile virus (WNV) has become an increasingly important public health problem and the cause of outbreaks of neurological disease. Genetic analyses have identified multiple lineages with many studies focusing on lineage 1 due to its emergence in New York in 1999 and its neuroinvasive phenotype. Until recently, viruses in lineage 2 were not thought to be of public health importance due to few outbreaks of disease being associated with viruses in this lineage. However, recent epidemics of lineage 2 in Europe (Greece and Italy) and Russia have shown the increasing importance of this lineage. There are very few genetic studies examining isolates belonging to lineage 2. We have sequenced the full-length genomes of four older lineage 2 WNV isolates, compared them to 12 previously published genomic sequences and examined the evolution of this lineage. Our studies show that this lineage has evolved over the past 300-400 years and appears to correlate with a change from mouse attenuated to virulent phenotype based on previous studies by our group. This evolution mirrors that which is seen in lineage 1 isolates, which have also evolved to a virulent phenotype over the same period of time.
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Affiliation(s)
- Allison R McMullen
- Department of Pathology, Center for Biodefense and Emerging Infectious Diseases, and Sealy Center for Vaccine Development, University of Texas Medical Branch, Galveston, TX 77555-0609, USA
| | - Harun Albayrak
- Department of Virology, Faculty of Veterinary Medicine, Ondokuz Mayis University, Samsun, 55139, Turkey.,Department of Pathology, Center for Biodefense and Emerging Infectious Diseases, and Sealy Center for Vaccine Development, University of Texas Medical Branch, Galveston, TX 77555-0609, USA
| | - Fiona J May
- Department of Pathology, Center for Biodefense and Emerging Infectious Diseases, and Sealy Center for Vaccine Development, University of Texas Medical Branch, Galveston, TX 77555-0609, USA
| | - C Todd Davis
- Department of Pathology, Center for Biodefense and Emerging Infectious Diseases, and Sealy Center for Vaccine Development, University of Texas Medical Branch, Galveston, TX 77555-0609, USA
| | - David W C Beasley
- Department of Pathology, Center for Biodefense and Emerging Infectious Diseases, and Sealy Center for Vaccine Development, University of Texas Medical Branch, Galveston, TX 77555-0609, USA
| | - Alan D T Barrett
- Department of Pathology, Center for Biodefense and Emerging Infectious Diseases, and Sealy Center for Vaccine Development, University of Texas Medical Branch, Galveston, TX 77555-0609, USA
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Martín-Acebes MA, Saiz JC. West Nile virus: A re-emerging pathogen revisited. World J Virol 2012; 1:51-70. [PMID: 24175211 PMCID: PMC3782267 DOI: 10.5501/wjv.v1.i2.51] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/19/2011] [Revised: 02/16/2012] [Accepted: 03/05/2012] [Indexed: 02/05/2023] Open
Abstract
West Nile virus (WNV), a flavivirus of the Flaviviridae family, is maintained in nature in an enzootic transmission cycle between avian hosts and ornithophilic mosquito vectors, although the virus occasionally infects other vertebrates. WNV causes sporadic disease outbreaks in horses and humans, which may result in febrile illness, meningitis, encephalitis and flaccid paralysis. Until recently, its medical and veterinary health concern was relatively low; however, the number, frequency and severity of outbreaks with neurological consequences in humans and horses have lately increased in Europe and the Mediterranean basin. Since its introduction in the Americas, the virus spread across the continent with worrisome consequences in bird mortality and a considerable number of outbreaks among humans and horses, which have resulted in the largest epidemics of neuroinvasive WNV disease ever documented. Surprisingly, its incidence in human and animal health is very different in Central and South America, and the reasons for it are not yet understood. Even though great advances have been obtained lately regarding WNV infection, and although efficient equine vaccines are available, no specific treatments or vaccines for human use are on the market. This review updates the most recent investigations in different aspects of WNV life cycle: molecular virology, transmission dynamics, host range, clinical presentations, epidemiology, ecology, diagnosis, control, and prevention, and highlights some aspects that certainly require further research.
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Affiliation(s)
- Miguel A Martín-Acebes
- Miguel A Martín-Acebes, Juan-Carlos Saiz, Department of Biotechnology, Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria, 28040 Madrid, Spain
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Anderson JF, Main AJ, Cheng G, Ferrandino FJ, Fikrig E. Horizontal and vertical transmission of West Nile virus genotype NY99 by Culex salinarius and genotypes NY99 and WN02 by Culex tarsalis. Am J Trop Med Hyg 2012; 86:134-9. [PMID: 22232464 DOI: 10.4269/ajtmh.2012.11-0473] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
Culex tarsalis is a superior horizontal and vertical vector of West Nile virus (WNV) compared with Culex salinarius. Culex salinarius transmitted WNV genotype NY99 (CT 2741-99 strain) horizontally to suckling mice at significantly lower rates than Cx. tarsalis on Days 8, 9, 10, and 12 post-infection, and Cx. salinarius transmitted WNV genotype NY99 to offspring at a lower vertical transmission infection rate than Cx. tarsalis. Culex tarsalis transmitted WNV genotypes NY99 and WN02 (CT S0084-08 strain) with equal efficiency. Daily percent horizontal transmission of genotype NY99 by Cx. tarsalis-infected per os and by intra-thoracic infection was not significantly different from daily transmission of genotype WN02 from Days 5-23 and Days 2-9 post-infection, respectively. Our findings do not support the previously published hypothesis that genotype NY99 was replaced in the New World by WN02 because of a shorter extrinsic incubation of WN02.
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Affiliation(s)
- John F Anderson
- Department of Entomology and Center for Vector Biology and Zoonotic Diseases, The Connecticut Agricultural Experiment Station, New Haven, Connecticut, USA.
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31
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Pesko KN, Ebel GD. West Nile virus population genetics and evolution. INFECTION GENETICS AND EVOLUTION 2011; 12:181-90. [PMID: 22226703 DOI: 10.1016/j.meegid.2011.11.014] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/17/2011] [Revised: 11/29/2011] [Accepted: 11/30/2011] [Indexed: 12/18/2022]
Abstract
West Nile virus (WNV) (Flaviviridae: Flavivirus) is transmitted from mosquitoes to birds, but can cause fatal encephalitis in infected humans. Since its introduction into North America in New York in 1999, it has spread throughout the western hemisphere. Multiple outbreaks have also occurred in Europe over the last 20 years. This review highlights recent efforts to understand how host pressures impact viral population genetics, genotypic and phenotypic changes which have occurred in the WNV genome as it adapts to this novel environment, and molecular epidemiology of WNV worldwide. Future research directions are also discussed.
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Affiliation(s)
- Kendra N Pesko
- Department of Pathology, University of New Mexico School of Medicine, 1 University of New Mexico, Albuquerque, NM 87131, USA
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Brackney DE, Pesko KN, Brown IK, Deardorff ER, Kawatachi J, Ebel GD. West Nile virus genetic diversity is maintained during transmission by Culex pipiens quinquefasciatus mosquitoes. PLoS One 2011; 6:e24466. [PMID: 21935412 PMCID: PMC3171416 DOI: 10.1371/journal.pone.0024466] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2011] [Accepted: 08/10/2011] [Indexed: 11/18/2022] Open
Abstract
Due to error-prone replication, RNA viruses exist within hosts as a heterogeneous population of non-identical, but related viral variants. These populations may undergo bottlenecks during transmission that stochastically reduce variability leading to fitness declines. Such bottlenecks have been documented for several single-host RNA viruses, but their role in the population biology of obligate two-host viruses such as arthropod-borne viruses (arboviruses) in vivo is unclear, but of central importance in understanding arbovirus persistence and emergence. Therefore, we tracked the composition of West Nile virus (WNV; Flaviviridae, Flavivirus) populations during infection of the vector mosquito, Culex pipiens quinquefasciatus to determine whether WNV populations undergo bottlenecks during transmission by this host. Quantitative, qualitative and phylogenetic analyses of WNV sequences in mosquito midguts, hemolymph and saliva failed to document reductions in genetic diversity during mosquito infection. Further, migration analysis of individual viral variants revealed that while there was some evidence of compartmentalization, anatomical barriers do not impose genetic bottlenecks on WNV populations. Together, these data suggest that the complexity of WNV populations are not significantly diminished during the extrinsic incubation period of mosquitoes.
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Affiliation(s)
- Doug E. Brackney
- Department of Pathology, University of New Mexico School of Medicine, Albuquerque, New Mexico, United States of America
| | - Kendra N. Pesko
- Department of Pathology, University of New Mexico School of Medicine, Albuquerque, New Mexico, United States of America
| | - Ivy K. Brown
- Department of Pathology, University of New Mexico School of Medicine, Albuquerque, New Mexico, United States of America
| | - Eleanor R. Deardorff
- Department of Pathology, University of New Mexico School of Medicine, Albuquerque, New Mexico, United States of America
| | - Jon Kawatachi
- Department of Pathology, University of New Mexico School of Medicine, Albuquerque, New Mexico, United States of America
| | - Gregory D. Ebel
- Department of Pathology, University of New Mexico School of Medicine, Albuquerque, New Mexico, United States of America
- * E-mail:
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McMullen AR, May FJ, Li L, Guzman H, Bueno R, Dennett JA, Tesh RB, Barrett ADT. Evolution of new genotype of West Nile virus in North America. Emerg Infect Dis 2011; 17:785-93. [PMID: 21529385 PMCID: PMC3321787 DOI: 10.3201/eid1705.101707] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Previous studies of North American isolates of West Nile virus (WNV) during 1999–2005 suggested that the virus had reached genetic homeostasis in North America. However, genomic sequencing of WNV isolates from Harris County, Texas, during 2002–2009 suggests that this is not the case. Three new genetic groups have been identified in Texas since 2005. Spread of the southwestern US genotype (SW/WN03) from the Arizona/Colorado/northern Mexico region to California, Illinois, New Mexico, New York, North Dakota, and the Texas Gulf Coast demonstrates continued evolution of WNV. Thus, WNV continues to evolve in North America, as demonstrated by selection of this new genotype. Continued surveillance of the virus is essential as it continues to evolve in the New World.
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Abstract
Zoonotic West Nile virus (WNV) circulates in natural transmission cycles involving certain mosquitoes and birds, horses, humans, and a range of other vertebrates are incidental hosts. Clinical infections in humans can range in severity from uncomplicated WNV fever to fatal meningoencephalitis. Since its introduction to the Western Hemisphere in 1999, WNV had spread across North America, Central and South America and the Caribbean, although the vast majority of severe human cases have occurred in the United States of America (USA) and Canada. By 2002-2003, the WNV outbreaks have involved thousands of patients causing severe neurologic disease (meningoencephalitis and poliomyelitis-like syndrome) and hundreds of associated fatalities in USA. The purpose of this review is to present recent information on the epidemiology and pathogenicity of WNV since its emergence in North America.
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Phylogeography of West Nile virus: from the cradle of evolution in Africa to Eurasia, Australia, and the Americas. J Virol 2010; 85:2964-74. [PMID: 21159871 DOI: 10.1128/jvi.01963-10] [Citation(s) in RCA: 184] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
West Nile virus (WNV) is the most widely distributed of the encephalitic flaviviruses and is a major cause of encephalitis, with isolates obtained from all continents, apart from Antarctica. Subsequent to its divergence from the other members of the Japanese encephalitis virus complex, presumably in Africa, WNV has diverged into individual lineages that mostly correspond with geographic distribution. Here we elucidate the phylogeography and evolutionary history of isolates from lineage 1 of WNV. Interestingly, there are many examples of the same amino acid having evolved independently on multiple occasions. In Africa, WNV exists in an endemic cycle, whereas it is epidemic in Europe, being reintroduced regularly from Africa either directly (in western Europe) or via the Middle East (in eastern Europe). Significantly, introduction into other geographic areas has occurred on one occasion only in each region, leading to subsequent establishment and expansion of the virus in these areas. Only one endemic genotype each is present in India and Australia, suggesting that WNV was successfully introduced into these locations once only. Each introduction occurred many centuries ago, probably due to trade and exploration during the 19th century. Likewise, in the Americas, WNV was successfully introduced in 1999 and subsequently became endemic across most temperate regions of North America (NA). In contrast to previous suggestions, an isolate from the epidemic in Israel in 1998 was not the direct progenitor of the NA epidemic; rather, both epidemics originated from the same (unknown) location.
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Pesko KN, Torres-Perez F, Hjelle BL, Ebel GD. Molecular epidemiology of Powassan virus in North America. J Gen Virol 2010; 91:2698-705. [PMID: 20631087 PMCID: PMC3052558 DOI: 10.1099/vir.0.024232-0] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Powassan virus (POW) is a tick-borne flavivirus distributed in Canada, the northern USA and the Primorsky region of Russia. POW is the only tick-borne flavivirus endemic to the western hemisphere, where it is transmitted mainly between Ixodes cookei and groundhogs (Marmota monax). Deer tick virus (DTV), a genotype of POW that has been frequently isolated from deer ticks (Ixodes scapularis), appears to be maintained in an enzootic cycle between these ticks and white-footed mice (Peromyscus leucopus). DTV has been isolated from ticks in several regions of North America, including the upper Midwest and the eastern seaboard. The incidence of human disease due to POW is apparently increasing. Previous analysis of tick-borne flaviviruses endemic to North America have been limited to relatively short genome fragments. We therefore assessed the evolutionary dynamics of POW using newly generated complete and partial genome sequences. Maximum-likelihood and Bayesian phylogenetic inferences showed two well-supported, reciprocally monophyletic lineages corresponding to POW and DTV. Bayesian skyline plots based on year-of-sampling data indicated no significant population size change for either virus lineage. Statistical model-based selection analyses showed evidence of purifying selection in both lineages. Positive selection was detected in NS-5 sequences for both lineages and envelope sequences for POW. Our findings confirm that POW and DTV sequences are relatively stable over time, which suggests strong evolutionary constraint, and support field observations that suggest that tick-borne flavivirus populations are extremely stable in enzootic foci.
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Affiliation(s)
- Kendra N Pesko
- Department of Pathology, University of New Mexico School of Medicine, Albuquerque, NM, USA
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37
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May FJ, Li L, Davis CT, Galbraith SE, Barrett ADT. Multiple pathways to the attenuation of West Nile virus in south-east Texas in 2003. Virology 2010; 405:8-14. [PMID: 20580395 DOI: 10.1016/j.virol.2010.04.022] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2010] [Revised: 03/23/2010] [Accepted: 04/22/2010] [Indexed: 11/15/2022]
Abstract
West Nile virus (WNV) was first detected in Texas in 2002. During 2003, several isolates exhibiting significant attenuation of mouse neuroinvasiveness, and in some cases a small plaque and temperature sensitive phenotype when compared to other North American WNV isolates, were obtained from birds and mosquitoes in South-East Texas. To determine the attenuation markers of WNV, we have sequenced the genomes of three attenuated isolates and four temporally related virulent isolates and compared the amino acid substitutions in a total of 101 isolates, including three previously published genomes of attenuated strains, to identify mutations that are potentially involved in attenuation. Surprisingly, the attenuated strains fall into three separate "groups", suggesting that the attenuated phenotype evolved on three separate occasions in 2003. None of the groups share the same nucleotide changes or amino acid substitutions, and there are few mutations that can be clearly defined alone as being associated with attenuation.
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Affiliation(s)
- Fiona J May
- Department of Pathology, Center for Biodefense and Emerging Infectious Diseases, Institute for Human Infections and Immunity, and Sealy Center for Vaccine Development, University of Texas Medical Branch, Galveston, TX 77555-0436, USA
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38
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Christofferson RC, Roy AF, Mores CN. Factors associated with mosquito pool positivity and the characterization of the West Nile viruses found within Louisiana during 2007. Virol J 2010; 7:139. [PMID: 20579348 PMCID: PMC2903561 DOI: 10.1186/1743-422x-7-139] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2010] [Accepted: 06/25/2010] [Indexed: 11/10/2022] Open
Abstract
Background West Nile virus (WNV) is an arbovirus of public health importance in the genus Flavivirus, a group of positive sense RNA viruses. The NS3 gene has a high level of substitutions and is phylogenetically informative. Likewise, substitutions in the envelope region have been postulated to enable viruses to subvert immune responses. Analysis of these genes among isolates from positive mosquitoes collected in Louisiana illustrates the variation present in the regions and provides improved insight to a phylogenetic model. Employing a GIS eco-regionalization method, we hypothesized that WNV pool positivity was correlated with regional environmental characteristics. Further, we postulated that the phylogenetic delineations would be associated with variations in regional environmental conditions. Results Type of regional land cover was a significant effect (p < 0.0001) in the positive pool prediction, indicating that there is an ecological component driving WNV activity. Additionally, month of collection was significant (p < 0.0001); and thus there is a temporal component that contributes to the probability of getting a positive mosquito pool. All virus isolates are of the WNV 2002 lineage. There appears to be some diversity within both forested and wetland areas; and the possibility of a distinct clade in the wetland samples. Conclusions The phylogenetic analysis shows that there has been no reversion in Louisiana from the 2002 lineage which replaced the originally introduced strain. Our pool positivity model serves as a basis for future testing, and could direct mosquito control and surveillance efforts. Understanding how land cover and regional ecology effects mosquito pool positivity will greatly help focus mosquito abatement efforts. This would especially help in areas where abatement programs are limited due to either funding or man power. Moreover, understanding how regional environments drive phylogenetic variation will lead to a greater understanding of the interactions between ecology and disease prevalence.
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Affiliation(s)
- Rebecca C Christofferson
- Department of Pathobiological Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge, Louisiana, USA
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Brackney DE, Brown IK, Nofchissey RA, Fitzpatrick KA, Ebel GD. Homogeneity of Powassan virus populations in naturally infected Ixodes scapularis. Virology 2010; 402:366-71. [PMID: 20434750 DOI: 10.1016/j.virol.2010.03.035] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2009] [Revised: 12/02/2009] [Accepted: 03/23/2010] [Indexed: 12/22/2022]
Abstract
Powassan virus (POWV, Flaviviridae: Flavivirus) is the sole North American member of the tick-borne encephalitis complex and consists of two distinct lineages that are maintained in ecologically discrete enzootic transmission cycles. The underlying genetic mechanisms that lead to niche partitioning in arboviruses are poorly understood. Therefore, intra- and interhost genetic diversity was analyzed to determine if POWV exists as a quasispecies in nature and quantify selective pressures within and between hosts. In contrast to previous reports for West Nile virus (WNV), significant intrahost genetic diversity was not observed. However, pN (0.238) and d(N)/d(S) ratios (0.092) for interhost diversity were similar to those of WNV. Combined, these data suggest that purifying selection and/or population bottlenecks constrain quasispecies diversity within ticks. These same selective and stochastic mechanisms appear to drive minor sequence changes between ticks. Moreover, Powassan virus populations seem not to be structured as quasispecies in naturally infected adult deer ticks.
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Affiliation(s)
- Doug E Brackney
- University of New Mexico School of Medicine, Department of Pathology, Albuquerque, New Mexico, USA
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40
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Girard YA, Mayhew GF, Fuchs JF, Li H, Schneider BS, McGee CE, Rocheleau TA, Helmy H, Christensen BM, Higgs S, Bartholomay LC. Transcriptome changes in Culex quinquefasciatus (Diptera: Culicidae) salivary glands during West Nile virus infection. JOURNAL OF MEDICAL ENTOMOLOGY 2010; 47:421-435. [PMID: 20496590 DOI: 10.1603/me09249] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Persistent West Nile virus (WNV) infection in the mosquito Culex quinquefasciatus Say (Diptera: Culicidae) is associated with pathological changes in the salivary glands, including apoptotic cell death and a corresponding reduction in virus transmission over time. The vector host response to WNV infection and the molecular basis of WNV pathogenesis in Cx. quinquefasciatus was investigated using oligonucleotide microarrays designed to detect differences in the salivary gland transcriptome between WNV-infected mosquitoes and uninfected controls. Transcripts with increased abundance in infected salivary glands included those related to immunity, transcription, protein transport and degradation, amino acid and nucleotide metabolism, signal transduction, and cellular detoxification. Microarray-based analysis detected a decrease in transcript levels of a Culex inhibitor of apoptosis gene (IAP-1) and a decrease in abundance of 11 transcripts encoding salivary gland proteins. Transcript levels for an endonuclease, a proline-rich mucin, and several D7 protein family members also decreased. Transcripts with the greatest change in abundance during infection had either no similarity to sequences found in GenBank, VectorBase, and FlyBase, or were similar to sequences with uncharacterized protein products. These transcripts represent exciting targets for future analysis. Results from this study suggest that WNV infection influences transcriptional changes in an invertebrate host target tissue that may confer an advantage to the replicating virus, induce a host defense response, and alter the composition of vector saliva. The ramifications of these changes are discussed in terms of mosquito vector competence and WNV pathogenesis.
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Affiliation(s)
- Yvette A Girard
- Department of Pathology, University of Texas Medical Branch, 301 University Blvd., Galveston, TX 77555-0609, USA
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Drake JM. Evolutionary relationships among human-isolated and wildlife-isolated West Nile viruses. INFECTION, GENETICS AND EVOLUTION : JOURNAL OF MOLECULAR EPIDEMIOLOGY AND EVOLUTIONARY GENETICS IN INFECTIOUS DISEASES 2009; 9:1392-1393. [PMID: 19660578 DOI: 10.1016/j.meegid.2009.07.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/10/2009] [Revised: 07/23/2009] [Accepted: 07/27/2009] [Indexed: 05/28/2023]
Abstract
The evolutionary relationships among pathogen lineages in multi-host systems are often the only observable signature of unobserved ecological and epidemiological processes. The evolution of viruses infecting humans, particularly, is of interest because of the public health importance of understanding the relationship of virus exposure to disease risk. Here I report results of two analyses of the evolutionary relationships among West Nile viruses in North America. These analyses suggest that (1) assortative mixing occurs between virus groups and human vs. non-human hosts and (2) human-derived isolates are related to each other. The ecological processes generating these viruses and the epidemiological consequences of West Nile virus host preference are unknown.
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Affiliation(s)
- John M Drake
- Odum School of Ecology, University of Georgia, Athens, GA 30602-2202, USA.
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42
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Sultana H, Foellmer HG, Neelakanta G, Oliphant T, Engle M, Ledizet M, Krishnan MN, Bonafé N, Anthony KG, Marasco WA, Kaplan P, Montgomery RR, Diamond MS, Koski RA, Fikrig E. Fusion loop peptide of the West Nile virus envelope protein is essential for pathogenesis and is recognized by a therapeutic cross-reactive human monoclonal antibody. THE JOURNAL OF IMMUNOLOGY 2009; 183:650-60. [PMID: 19535627 DOI: 10.4049/jimmunol.0900093] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
West Nile virus is an emerging pathogen that can cause fatal neurological disease. A recombinant human mAb, mAb11, has been described as a candidate for the prevention and treatment of West Nile disease. Using a yeast surface display epitope mapping assay and neutralization escape mutant, we show that mAb11 recognizes the fusion loop, at the distal end of domain II of the West Nile virus envelope protein. Ab mAb11 cross-reacts with all four dengue viruses and provides protection against dengue (serotypes 2 and 4) viruses. In contrast to the parental West Nile virus, a neutralization escape variant failed to cause lethal encephalitis (at higher infectious doses) or induce the inflammatory responses associated with blood-brain barrier permeability in mice, suggesting an important role for the fusion loop in viral pathogenesis. Our data demonstrate that an intact West Nile virus fusion loop is critical for virulence, and that human mAb11 targeting this region is efficacious against West Nile virus infection. These experiments define the molecular determinant on the envelope protein recognized by mAb11 and demonstrate the importance of this region in causing West Nile encephalitis.
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Affiliation(s)
- Hameeda Sultana
- Department of Internal Medicine, Yale University School of Medicine, New Haven, CT 06520, USA
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Brault AC. Changing patterns of West Nile virus transmission: altered vector competence and host susceptibility. Vet Res 2009; 40:43. [PMID: 19406093 PMCID: PMC2695027 DOI: 10.1051/vetres/2009026] [Citation(s) in RCA: 79] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2009] [Accepted: 04/29/2009] [Indexed: 12/11/2022] Open
Abstract
West Nile virus (WNV) is a flavivirus (Flaviviridae) transmitted between Culex spp. mosquitoes and avian hosts. The virus has dramatically expanded its geographic range in the past ten years. Increases in global commerce, climate change, ecological factors and the emergence of novel viral genotypes likely play significant roles in the emergence of this virus; however, the exact mechanism and relative importance of each is uncertain. Previously WNV was primarily associated with febrile illness of children in endemic areas, but it was identified as a cause of neurological disease in humans in 1994. This modulation in disease presentation could be the result of the emergence of a more virulent genotype as well as the progression of the virus into areas in which the age structure of immunologically naïve individuals makes them more susceptible to severe neurological disease. Since its introduction to North America in 1999, a novel WNV genotype has been identified that has been demonstrated to disseminate more rapidly and with greater efficiency at elevated temperatures than the originally introduced strain, indicating the potential importance of temperature as a selective criteria for the emergence of WNV genotypes with increased vectorial capacity. Even prior to the North American introduction, a mutation associated with increased replication in avian hosts, identified to be under adaptive evolutionary pressure, has been identified, indicating that adaptation for increased replication within vertebrate hosts could play a role in increased transmission efficiency. Although stable in its evolutionary structure, WNV has demonstrated the capacity for rapidly adapting to both vertebrate hosts and invertebrate vectors and will likely continue to exploit novel ecological niches as it adapts to novel transmission foci.
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Affiliation(s)
- Aaron C Brault
- Department of Pathology, Microbiology and Immunology, School of Veterinary Medicine, University of California, Davis, CA 95616, USA.
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44
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Gould EA, Higgs S. Impact of climate change and other factors on emerging arbovirus diseases. Trans R Soc Trop Med Hyg 2009; 103:109-21. [PMID: 18799177 PMCID: PMC2915563 DOI: 10.1016/j.trstmh.2008.07.025] [Citation(s) in RCA: 284] [Impact Index Per Article: 18.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2008] [Revised: 07/28/2008] [Accepted: 07/29/2008] [Indexed: 11/18/2022] Open
Abstract
While some skeptics remain unconvinced that global climate change is a reality, there is no doubt that during the past 50 years or so, patterns of emerging arbovirus diseases have changed significantly. Can this be attributed to climate change? Climate is a major factor in determining: (1) the geographic and temporal distribution of arthropods; (2) characteristics of arthropod life cycles; (3) dispersal patterns of associated arboviruses; (4) the evolution of arboviruses; and (5) the efficiency with which they are transmitted from arthropods to vertebrate hosts. Thus, under the influence of increasing temperatures and rainfall through warming of the oceans, and alteration of the natural cycles that stabilise climate, one is inevitably drawn to the conclusion that arboviruses will continue to emerge in new regions. For example, we cannot ignore the unexpected but successful establishment of chikungunya fever in northern Italy, the sudden appearance of West Nile virus in North America, the increasing frequency of Rift Valley fever epidemics in the Arabian Peninsula, and very recently, the emergence of Bluetongue virus in northern Europe. In this brief review we ask the question, are these diseases emerging because of climate change or do other factors play an equal or even more important role in their emergence?
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Affiliation(s)
- E A Gould
- Unité des Virus Emergents, Faculté de Médecine Timone, 13385 Marseille, Cedex 05, France.
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Grinev A, Daniel S, Stramer S, Rossmann S, Caglioti S, Rios M. Genetic variability of West Nile virus in US blood donors, 2002-2005. Emerg Infect Dis 2008; 14:436-44. [PMID: 18325259 PMCID: PMC2570840 DOI: 10.3201/eid1403.070463] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
This virus is diverging from precursor isolates as its geographic distribution expands. West Nile virus (WNV) was detected in the United States in 1999, has reoccurred every summer since, and has become endemic. Transfusion transmission was documented in 2002, and screening of blood donations for WNV began in 2003. We investigated genetic variation of WNV in human isolates obtained from specimens collected from 30 infected blood donors who tested positive for WNV RNA during 2002–2005. Complete genomic sequences of 8 isolates and structural gene sequences from 22 additional isolates were analyzed. We found some genetic diversity in isolates from different geographic regions and genetic divergence from reported sequences from epidemics in 1999–2001. Nucleotide divergence of structural genes showed a small increase from 2002 (0.18%) to 2005 (0.37%), suggesting absence of strong selective pressure and limited genetic evolution of WNV during that period. Nevertheless, WNV has continued to diverge from precursor isolates as geographic distribution of the virus has expanded.
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46
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Development of multiplex PCR-ligase detection reaction assay for detection of West Nile virus. J Clin Microbiol 2008; 46:2269-79. [PMID: 18495862 DOI: 10.1128/jcm.02335-07] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
We have developed a novel multiplex reverse transcription-PCR ligase detection reaction (RT-PCR/LDR) assay for the detection of West Nile virus (WNV) in both clinical and mosquito pool samples. The method relies on the amplification of three different genomic regions, one in the coding sequence of nonstructural protein NS2a and two in nonstructural protein NS5, to minimize the risk of detection failure due to genetic variation. The sensitivity of the PCR is complemented by the high specificity of the LDR step, and the detection of the LDR products can be achieved with capillary electrophoresis (CE) or a universal DNA microarray. We evaluated the limit of detection by both one-step and two-step multiplex RT-PCR/LDR/CE approaches, which reached, respectively, 0.005 and 0.017 PFU. The assay demonstrated 99% sensitivity when mosquito pool samples were tested and 100% sensitivity with clinical samples when the one-step approach was used. The broad strain coverage was confirmed by testing 34 WNV isolates belonging to lineages 1 and 2, and the high specificity of the assay was determined by testing other flaviviruses, as well as negative mosquito pool and clinical samples. In summary, the multiplex RT-PCR/LDR assay could represent a valuable complement to WNV serological diagnosis, especially in early symptomatic patients. In addition, the multiplexing capacity of the technique, which can be coupled to universal DNA microarray detection, makes it an amenable tool to develop a more comprehensive assay for viral pathogens.
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47
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Kramer LD, Styer LM, Ebel GD. A global perspective on the epidemiology of West Nile virus. ANNUAL REVIEW OF ENTOMOLOGY 2008; 53:61-81. [PMID: 17645411 DOI: 10.1146/annurev.ento.53.103106.093258] [Citation(s) in RCA: 342] [Impact Index Per Article: 21.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
West Nile virus (WNV) (Flavivirus: Flaviviridae) is the most widespread arbovirus in the world. A significant range expansion occurred beginning in 1999 when the virus was introduced into New York City. This review highlights recent research into WNV epizootiology and epidemiology, including recent advances in understanding of the host-virus interaction at the molecular, organismal, and ecological levels. Vector control strategies, vaccines, and antivirals, which now must be considered on a global scale, are also discussed.
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Affiliation(s)
- Laura D Kramer
- The Arbovirus Laboratories, Wadsworth Center, New York State Department of Health, Slingerlands, NY 12159, USA.
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Schneider BS, McGee CE, Jordan JM, Stevenson HL, Soong L, Higgs S. Prior exposure to uninfected mosquitoes enhances mortality in naturally-transmitted West Nile virus infection. PLoS One 2007; 2:e1171. [PMID: 18000543 PMCID: PMC2048662 DOI: 10.1371/journal.pone.0001171] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2007] [Accepted: 10/20/2007] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND The global emergence of West Nile virus (WNV) has highlighted the importance of mosquito-borne viruses. These are inoculated in vector saliva into the vertebrate skin and circulatory system. Arthropod-borne (arbo)viruses such as WNV are transmitted to vertebrates as an infectious mosquito probes the skin for blood, depositing the virus and saliva into the skin and circulation. Growing evidence has demonstrated that arthropod, and recently mosquito, saliva can have a profound effect on pathogen transmission efficiency, pathogenesis, and disease course. A potentially important aspect of natural infections that has been ignored is that in nature vertebrates are typically exposed to the feeding of uninfected mosquitoes prior to the mosquito that transmits WNV. The possibility that pre-exposure to mosquito saliva might modulate WNV infection was explored. PRINCIPAL FINDINGS Here we report that sensitization to mosquito saliva exacerbates viral infection. Prior exposure of mice to mosquito feeding resulted in increased mortality following WNV infection. This aggravated disease course was associated with enhanced early viral replication, increased interleukin-10 expression, and elevated influx of WNV-susceptible cell types to the inoculation site. This exacerbated disease course was mimicked by passive transfer of mosquito-sensitized serum. SIGNIFICANCE This is the first report that sensitization to arthropod saliva can exacerbate arthropod-borne infection, contrary to previous studies with parasite and bacteria infections. This research suggests that in addition to the seroreactivity of the host to virus, it is important to take into account the immune response to vector feeding.
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Affiliation(s)
- Bradley S. Schneider
- Department of Pathology, Center for Biodefense and Emerging Infectious Diseases, University of Texas Medical Branch, Galveston, Texas, United States of America
- Pasteur Institute, Paris, France
| | - Charles E. McGee
- Department of Pathology, Center for Biodefense and Emerging Infectious Diseases, University of Texas Medical Branch, Galveston, Texas, United States of America
| | - Jeffrey M. Jordan
- Department of Pathology, Center for Biodefense and Emerging Infectious Diseases, University of Texas Medical Branch, Galveston, Texas, United States of America
| | - Heather L. Stevenson
- Department of Pathology, Center for Biodefense and Emerging Infectious Diseases, University of Texas Medical Branch, Galveston, Texas, United States of America
| | - Lynn Soong
- Department of Pathology, Center for Biodefense and Emerging Infectious Diseases, University of Texas Medical Branch, Galveston, Texas, United States of America
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, Texas, United States of America
| | - Stephen Higgs
- Department of Pathology, Center for Biodefense and Emerging Infectious Diseases, University of Texas Medical Branch, Galveston, Texas, United States of America
- * To whom correspondence should be addressed. E-mail:
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Davis CT, Li L, May FJ, Bueno R, Dennett JA, Bala AA, Guzman H, Elizondo-Quiroga D, Tesh RB, Barrett AD. Genetic stasis of dominant West Nile virus genotype, Houston, Texas. Emerg Infect Dis 2007; 13:601-4. [PMID: 17553276 PMCID: PMC2725985 DOI: 10.3201/eid1304.061473] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
The accumulation and fixation of mutations in West Nile virus (WNV) led to the emergence of a dominant genotype throughout North America. Subsequent analysis of 44 isolates, including 19 new sequences, from Houston, Texas, suggests that WNV has reached relative genetic stasis at the local level in recent years.
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Affiliation(s)
- C. Todd Davis
- University of Texas Medical Branch, Galveston, Texas, USA
- Current affiliation: Centers for Disease Control and Prevention, Atlanta, Georgia, USA
| | - Li Li
- University of Texas Medical Branch, Galveston, Texas, USA
| | - Fiona J. May
- University of Texas Medical Branch, Galveston, Texas, USA
| | - Rudy Bueno
- Harris County Public Health and Environmental Services, Houston, Texas, USA
| | - James A. Dennett
- Harris County Public Health and Environmental Services, Houston, Texas, USA
| | - Adil A. Bala
- Harris County Public Health and Environmental Services, Houston, Texas, USA
| | - Hilda Guzman
- University of Texas Medical Branch, Galveston, Texas, USA
| | | | - Robert B. Tesh
- University of Texas Medical Branch, Galveston, Texas, USA
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Jia Y, Moudy RM, Dupuis AP, Ngo KA, Maffei JG, Jerzak GVS, Franke MA, Kauffman EB, Kramer LD. Characterization of a small plaque variant of West Nile virus isolated in New York in 2000. Virology 2007; 367:339-47. [PMID: 17617432 PMCID: PMC2190729 DOI: 10.1016/j.virol.2007.06.008] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2007] [Revised: 04/07/2007] [Accepted: 06/07/2007] [Indexed: 11/29/2022]
Abstract
A small-plaque variant (SP) of West Nile virus (WNV) was isolated in Vero cell culture from kidney tissue of an American crow collected in New York in 2000. The in vitro growth of the SP and parental (WT) strains was characterized in mammalian (Vero), avian (DF-1 and PDE), and mosquito (C6/36) cells. The SP variant replicated less efficiently than did the WT in Vero cells. In avian cells, SP growth was severely restricted at high temperatures, suggesting that the variant is temperature sensitive. In mosquito cells, growth of SP and WT was similar, but in vivo in Culex pipiens (L.) there were substantial differences. Relative to WT, SP exhibited reduced replication following intrathoracic inoculation and lower infection, dissemination, and transmission rates following oral infection. Analysis of the full length sequence of the SP variant identified sequence differences which led to only two amino acid substitutions relative to WT, prM P54S and NS2A V61A.
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Affiliation(s)
- Yongqing Jia
- The Arbovirus Laboratories, Wadsworth Center, New York State Department of Health, Slingerlands, New York 12159
| | - Robin M. Moudy
- The Arbovirus Laboratories, Wadsworth Center, New York State Department of Health, Slingerlands, New York 12159
| | - Alan P. Dupuis
- The Arbovirus Laboratories, Wadsworth Center, New York State Department of Health, Slingerlands, New York 12159
| | - Kiet A. Ngo
- The Arbovirus Laboratories, Wadsworth Center, New York State Department of Health, Slingerlands, New York 12159
| | - Joseph G. Maffei
- The Arbovirus Laboratories, Wadsworth Center, New York State Department of Health, Slingerlands, New York 12159
| | - Greta V. S. Jerzak
- The Arbovirus Laboratories, Wadsworth Center, New York State Department of Health, Slingerlands, New York 12159
| | - Mary A. Franke
- The Arbovirus Laboratories, Wadsworth Center, New York State Department of Health, Slingerlands, New York 12159
| | - Elizabeth B. Kauffman
- The Arbovirus Laboratories, Wadsworth Center, New York State Department of Health, Slingerlands, New York 12159
| | - Laura D. Kramer
- The Arbovirus Laboratories, Wadsworth Center, New York State Department of Health, Slingerlands, New York 12159
- Department of Biomedical Sciences, School of Public Health, State University of New York at Albany, Albany, New York 12201
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