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Salivary gland extract from the deer tick, Ixodes scapularis, facilitates neuroinvasion by Powassan virus in BALB/c mice. Sci Rep 2021; 11:20873. [PMID: 34686683 PMCID: PMC8536725 DOI: 10.1038/s41598-021-00021-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2021] [Accepted: 09/28/2021] [Indexed: 12/30/2022] Open
Abstract
Powassan virus (POWV) is a neuroinvasive flavivirus transmitted to mammals by the bite of ixodid ticks. In this study, we sought to investigate the impact of tick salivary gland extract (SGE) on POWV neuroinvasion. BALB/c mice were footpad inoculated with either a high dose or a low dose of POWV, with and without Ixodes scapularis salivary gland extract. Brain and spinal cord were extracted daily, and immunohistochemical techniques were used for temporal tracking of POWV antigen. The temporal pattern of POWV staining showed a caudal to rostral spread of POWV in the brains of mice from both high dose infection groups. For the high dose infection groups, the presence of tick SGE did not influence the spread of POWV in the brain. Mice infected with the low dose of virus alone did not present POWV staining in the brain; however, in the presence of SGE, low dose infected mice presented scattered foci of POWV-infected cells throughout the brain. This study shows that tick SGE facilitates POWV neuroinvasion when mice are infected with the lower dose of POWV. We also found two patterns of central nervous system invasion that were directly influenced by the dose of POWV administered.
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2
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Park SL, Huang YJS, Lyons AC, Ayers VB, Hettenbach SM, McVey DS, Noronha LE, Burton KR, Hsu WW, Higgs S, Vanlandingham DL. Mosquito Saliva Modulates Japanese Encephalitis Virus Infection in Domestic Pigs. FRONTIERS IN VIROLOGY 2021. [DOI: 10.3389/fviro.2021.724016] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Japanese encephalitis virus (JEV) is a mosquito-borne flavivirus that is the leading cause of pediatric viral encephalitis in Asia. Japanese encephalitis virus is transmitted by Culex species mosquitoes that also vector several zoonotic flaviviruses. Despite the knowledge that mosquito saliva contains molecules that may alter flavivirus pathogenesis, whether or not the deposition of viruses by infected mosquitoes has an impact on the kinetics and severity of JEV infection has not been thoroughly examined, especially in mammalian species involved in the enzootic transmission. Most JEV pathogenesis models were established using needle inoculation. Mouse models for West Nile (WNV) and dengue (DENV) viruses have shown that mosquito saliva can potentiate flavivirus infections and exacerbate disease symptoms. In this study, we determined the impact of mosquito salivary components on the pathogenesis of JEV in pigs, a species directly involved in its transmission cycle as an amplifying host. Interestingly, co-injection of JEV and salivary gland extract (SGE) collected from Culex quinquefasciatus produced milder febrile illness and shortened duration of nasal shedding but had no demonstrable impact on viremia and neuroinvasion. Our findings highlight that mosquito salivary components can differentially modulate the outcomes of flavivirus infections in amplifying hosts and in mouse models.
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3
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Beranek MD, Quaglia AI, Peralta GC, Flores FS, Stein M, Diaz LA, Almirón WR, Contigiani MS. Culex interfor and Culex saltanensis (Diptera: Culicidae) are susceptible and competent to transmit St. Louis encephalitis virus (Flavivirus: Flaviviridae) in central Argentina. Trans R Soc Trop Med Hyg 2021; 114:725-729. [PMID: 32722771 DOI: 10.1093/trstmh/traa058] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2020] [Revised: 05/23/2020] [Accepted: 07/03/2020] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND St. Louis encephalitis virus (SLEV) is endemic and autochthonous on the American continent. Culex pipiens quinquefasciatus is a vector of SLEV; however, Culex interfor and Culex saltanensis have also been found to be naturally infected with SLEV. The aim of this study was to determine the vector competence of C. interfor and C. saltanensis for SLEV from Argentina compared with C. p. quinquefasciatus. METHODS Female of the Culex species were orally infected by feeding on viraemic chicks that had been inoculated with SLEV. Abdomens, legs and saliva blood-fed mosquitoes were analysed by viral plaque assay. RESULTS Mosquitoes were susceptible to orally acquired infection, dissemination and transmission of SLEV in the saliva. CONCLUSIONS Our results demonstrate that C. saltanensis and C. interfor are susceptible to SLEV and competent for its transmission.
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Affiliation(s)
- Mauricio D Beranek
- Área Entomología, Instituto de Medicina Regional, CONICET, Universidad Nacional del Nordeste, Resistencia, Chaco, Argentina.,Laboratorio de Arbovirus y Arenavirus, Instituto de Virología "Dr J. M. Vanella", CONICET, Facultad de Medicina, Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Agustín I Quaglia
- Laboratorio de Arbovirus y Arenavirus, Instituto de Virología "Dr J. M. Vanella", CONICET, Facultad de Medicina, Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Giovana C Peralta
- Instituto de Diversidad y Ecología Animal, CONICET, Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Fernando S Flores
- Laboratorio de Arbovirus y Arenavirus, Instituto de Virología "Dr J. M. Vanella", CONICET, Facultad de Medicina, Universidad Nacional de Córdoba, Córdoba, Argentina.,Laboratorio de Ecología de Enfermedades, Instituto de Ciencias Veterinarias del Litoral (ICiVet-Litoral), Universidad Nacional del Litoral, CONICET, Esperanza, Santa Fe, Argentina
| | - Marina Stein
- Área Entomología, Instituto de Medicina Regional, CONICET, Universidad Nacional del Nordeste, Resistencia, Chaco, Argentina
| | - Luis A Diaz
- Laboratorio de Arbovirus y Arenavirus, Instituto de Virología "Dr J. M. Vanella", CONICET, Facultad de Medicina, Universidad Nacional de Córdoba, Córdoba, Argentina.,Instituto de Investigaciones Biológicas y Tecnológicas, CONICET, Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Walter R Almirón
- Instituto de Investigaciones Biológicas y Tecnológicas, CONICET, Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Marta S Contigiani
- Laboratorio de Arbovirus y Arenavirus, Instituto de Virología "Dr J. M. Vanella", CONICET, Facultad de Medicina, Universidad Nacional de Córdoba, Córdoba, Argentina
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4
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Besson B, Basset J, Gatellier S, Chabrolles H, Chaze T, Hourdel V, Matondo M, Pardigon N, Choumet V. Comparison of a human neuronal model proteome upon Japanese encephalitis or West Nile Virus infection and potential role of mosquito saliva in neuropathogenesis. PLoS One 2020; 15:e0232585. [PMID: 32374750 PMCID: PMC7202638 DOI: 10.1371/journal.pone.0232585] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2019] [Accepted: 04/18/2020] [Indexed: 12/31/2022] Open
Abstract
Neurotropic flavivirus Japanese encephalitis virus (JEV) and West Nile virus (WNV) are amongst the leading causes of encephalitis. Using label-free quantitative proteomics, we identified proteins differentially expressed upon JEV (gp-3, RP9) or WNV (IS98) infection of human neuroblastoma cells. Data are available via ProteomeXchange with identifier PXD016805. Both viruses were associated with the up-regulation of immune response (IFIT1/3/5, ISG15, OAS, STAT1, IRF9) and the down-regulation of SSBP2 and PAM, involved in gene expression and in neuropeptide amidation respectively. Proteins associated to membranes, involved in extracellular matrix organization and collagen metabolism represented major clusters down-regulated by JEV and WNV. Moreover, transcription regulation and mRNA processing clusters were also heavily regulated by both viruses. The proteome of neuroblastoma cells infected by JEV or WNV was significantly modulated in the presence of mosquito saliva, but distinct patterns were associated to each virus. Mosquito saliva favored modulation of proteins associated with gene regulation in JEV infected neuroblastoma cells while modulation of proteins associated with protein maturation, signal transduction and ion transporters was found in WNV infected neuroblastoma cells.
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Affiliation(s)
- Benoit Besson
- Institut Pasteur, Environment and Infectious Risks Unit, Arbovirus Group, Paris, France
| | - Justine Basset
- Institut Pasteur, Environment and Infectious Risks Unit, Arbovirus Group, Paris, France
| | - Sandrine Gatellier
- Institut Pasteur, Environment and Infectious Risks Unit, Arbovirus Group, Paris, France
| | - Hélène Chabrolles
- Institut Pasteur, Environment and Infectious Risks Unit, Arbovirus Group, Paris, France
| | - Thibault Chaze
- Institut Pasteur, Plateforme Protéomique, Unité de Spectrométrie de Masse pour la Biologie (MSBio), Centre de Ressources et Recherches Technologiques (C2RT), USR CNRS, Paris, France
| | - Véronique Hourdel
- Institut Pasteur, Environment and Infectious Risks Unit, Arbovirus Group, Paris, France
- Institut Pasteur, Plateforme Protéomique, Unité de Spectrométrie de Masse pour la Biologie (MSBio), Centre de Ressources et Recherches Technologiques (C2RT), USR CNRS, Paris, France
| | - Mariette Matondo
- Institut Pasteur, Plateforme Protéomique, Unité de Spectrométrie de Masse pour la Biologie (MSBio), Centre de Ressources et Recherches Technologiques (C2RT), USR CNRS, Paris, France
| | - Nathalie Pardigon
- Institut Pasteur, Environment and Infectious Risks Unit, Arbovirus Group, Paris, France
| | - Valérie Choumet
- Institut Pasteur, Environment and Infectious Risks Unit, Arbovirus Group, Paris, France
- * E-mail:
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5
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Nemeth NM, Bosco-Lauth AM, Williams LM, Bowen RA, Brown JD. West Nile Virus Infection in Ruffed Grouse ( Bonasa umbellus): Experimental Infection and Protective Effects of Vaccination. Vet Pathol 2017; 54:901-911. [PMID: 28675106 DOI: 10.1177/0300985817717770] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Ruffed grouse ( Bonasa umbellus) population numbers in Pennsylvania dramatically declined during the early 2000s and have subsequently remained depressed throughout much of the state. While this decline has been temporally associated with the presence of West Nile virus (WNV), lack of information on the WNV susceptibility of this popular game bird species has limited the ability to interpret the potential impacts of WNV. To address this knowledge gap, virologic, immunologic, pathologic, and clinical responses as well as protective effects of vaccination following experimental WNV inoculation in ruffed grouse were assessed. Four of 10 (40%) naive, WNV-inoculated grouse succumbed to infection within 8 days and had moderate mean peak viremia titers (107.0 plaque-forming units [PFU]/ml serum); severe necrotizing myocarditis with widespread, corresponding immunohistochemical labeling; and minimal encephalitis. Grouse that survived to the prescribed end point of 14 days postinoculation (6/10; 60%) had slightly lower mean peak viremia titers (106.8 PFU/ml serum), moderate myocardial lesions, and more widespread brain lesions with rare corresponding immunohistochemical labeling. Vaccinated, WNV-inoculated birds ( n = 5) had lower mean peak viremia titers (103.6 PFU/ml serum) and minimal lesions, and sham-inoculated, in-contact control birds ( n = 3) had no evidence of infection. All surviving, inoculated birds seroconverted, and WNV-specific antibodies were detectable in serum and Nobuto filter paper strip-eluted blood samples. These data suggest that WNV could serve as an additional population pressure on ruffed grouse in regions where transmission levels are high and WNV competent, ornithophilic vectors exist.
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Affiliation(s)
- Nicole M Nemeth
- 1 Department of Pathobiology, Ontario Veterinary College, University of Guelph, Guelph, Ontario, Canada.,2 Canadian Wildlife Health Cooperative, University of Guelph, Guelph, Ontario, Canada
| | - Angela M Bosco-Lauth
- 3 Department of Biomedical Sciences, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO, USA
| | - Lisa M Williams
- 4 Bureau of Wildlife Management, Pennsylvania Game Commission, Harrisburg, PA, USA
| | - Richard A Bowen
- 3 Department of Biomedical Sciences, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO, USA
| | - Justin D Brown
- 5 Pennsylvania Game Commission, Animal Diagnostic Laboratory, Pennsylvania State University, University Park, PA, USA
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Léger P, Lozach PY. Bunyaviruses: from transmission by arthropods to virus entry into the mammalian host first-target cells. Future Virol 2015. [DOI: 10.2217/fvl.15.52] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The Bunyaviridae constitute a large family of animal RNA viruses distributed worldwide, most members of which are transmitted to vertebrate hosts by arthropods and can cause severe pathologies in humans and livestock. With an increasing number of outbreaks, arthropod-borne bunyaviruses (arbo-bunyaviruses) present a global threat to public health and agricultural productivity. Yet transmission, tropism, receptors and cell entry remain poorly characterized. The focus of this review is on the initial infection of mammalian hosts by arbo-bunyaviruses from cellular and molecular perspectives, with particular attention to the human host. We address current knowledge and advances regarding the identity of the first-target cells and the subsequent processes of entry and penetration into the cytosol. Aspects of the vector-to-host switch that influence the early steps of cell infection in mammalian skin, where incoming particles are introduced by infected arthropods, are also highlighted and discussed.
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Affiliation(s)
- Psylvia Léger
- CellNetworks – Cluster of Excellence & Department of Infectious Diseases, Virology, University Hospital Heidelberg, D-69120 Heidelberg, Germany
| | - Pierre-Yves Lozach
- CellNetworks – Cluster of Excellence & Department of Infectious Diseases, Virology, University Hospital Heidelberg, D-69120 Heidelberg, Germany
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7
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Abstract
Many arboviral diseases are uncontrolled, and the viruses that cause them are globally emerging or reemerging pathogens that produce significant disease throughout the world. The increased spread and prevalence of disease are occurring during a period of substantial scientific growth in the vector-borne disease research community. This growth has been supported by advances in genomics and proteomics, and by the ability to genetically alter disease vectors. For the first time, researchers are elucidating the molecular details of vector host-seeking behavior, the susceptibility of disease vectors to arboviruses, the immunological control of infection in disease vectors, and the determinants that facilitate transmission of arboviruses from a vector to a host. These discoveries are facilitating the development of novel strategies to combat arboviral disease, including the release of transgenic mosquitoes harboring dominant lethal genes, the introduction of arbovirus-blocking microbes into mosquito populations, and the development of acquisition- and transmission-blocking therapeutics. Understanding the role of the vector in arbovirus transmission has provided critical practical and theoretical tools to control arboviral disease.
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Affiliation(s)
- Michael J Conway
- Foundational Sciences, Central Michigan University College of Medicine, Mt. Pleasant, Michigan 48859
| | - Tonya M Colpitts
- Department of Tropical Medicine, Tulane University School of Public Health and Tropical Medicine, New Orleans, Louisiana 70112
| | - Erol Fikrig
- Department of Internal Medicine, Infectious Diseases Section, Yale University School of Medicine, New Haven, Connecticut 06520; .,Howard Hughes Medical Institute, Chevy Chase, Maryland 20815
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8
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Pages N, Bréard E, Urien C, Talavera S, Viarouge C, Lorca-Oro C, Jouneau L, Charley B, Zientara S, Bensaid A, Solanes D, Pujols J, Schwartz-Cornil I. Culicoides midge bites modulate the host response and impact on bluetongue virus infection in sheep. PLoS One 2014; 9:e83683. [PMID: 24421899 PMCID: PMC3885445 DOI: 10.1371/journal.pone.0083683] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2013] [Accepted: 11/06/2013] [Indexed: 12/04/2022] Open
Abstract
Many haematophagous insects produce factors that help their blood meal and coincidently favor pathogen transmission. However nothing is known about the ability of Culicoides midges to interfere with the infectivity of the viruses they transmit. Among these, Bluetongue Virus (BTV) induces a hemorrhagic fever- type disease and its recent emergence in Europe had a major economical impact. We observed that needle inoculation of BTV8 in the site of uninfected C. nubeculosus feeding reduced viraemia and clinical disease intensity compared to plain needle inoculation. The sheep that developed the highest local inflammatory reaction had the lowest viral load, suggesting that the inflammatory response to midge bites may participate in the individual sensitivity to BTV viraemia development. Conversely compared to needle inoculation, inoculation of BTV8 by infected C. nubeculosus bites promoted viraemia and clinical symptom expression, in association with delayed IFN- induced gene expression and retarded neutralizing antibody responses. The effects of uninfected and infected midge bites on BTV viraemia and on the host response indicate that BTV transmission by infected midges is the most reliable experimental method to study the physio-pathological events relevant to a natural infection and to pertinent vaccine evaluation in the target species. It also leads the way to identify the promoting viral infectivity factors of infected Culicoides in order to possibly develop new control strategies against BTV and other Culicoides transmitted viruses.
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Affiliation(s)
- Nonito Pages
- Centre de Recerca en Sanitat Animal CReSA, Universitat Autònoma de Barcelona – Institut de Recerca i Tecnologia Agroalimentaries, Bellaterra, Spain
| | - Emmanuel Bréard
- Virologie, Unité Mixte de Recherche UMR1161, Agence Nationale de Sécurité Sanitaire de l'Alimentation, de l'Environnement et du Travail – Institut National de la Recherche Agronomique – Ecole Nationale Vétérinaire d'Alfort, Maisons-Alfort, France
| | - Céline Urien
- Virologie et Immunologie Moléculaires, Unité de Recherche UR892, Institut National de la Recherche Agronomique, Jouy-en-Josas, France
| | - Sandra Talavera
- Centre de Recerca en Sanitat Animal CReSA, Universitat Autònoma de Barcelona – Institut de Recerca i Tecnologia Agroalimentaries, Bellaterra, Spain
| | - Cyril Viarouge
- Virologie, Unité Mixte de Recherche UMR1161, Agence Nationale de Sécurité Sanitaire de l'Alimentation, de l'Environnement et du Travail – Institut National de la Recherche Agronomique – Ecole Nationale Vétérinaire d'Alfort, Maisons-Alfort, France
| | - Cristina Lorca-Oro
- Centre de Recerca en Sanitat Animal CReSA, Universitat Autònoma de Barcelona – Institut de Recerca i Tecnologia Agroalimentaries, Bellaterra, Spain
| | - Luc Jouneau
- Virologie et Immunologie Moléculaires, Unité de Recherche UR892, Institut National de la Recherche Agronomique, Jouy-en-Josas, France
| | - Bernard Charley
- Virologie et Immunologie Moléculaires, Unité de Recherche UR892, Institut National de la Recherche Agronomique, Jouy-en-Josas, France
| | - Stéphan Zientara
- Virologie, Unité Mixte de Recherche UMR1161, Agence Nationale de Sécurité Sanitaire de l'Alimentation, de l'Environnement et du Travail – Institut National de la Recherche Agronomique – Ecole Nationale Vétérinaire d'Alfort, Maisons-Alfort, France
| | - Albert Bensaid
- Centre de Recerca en Sanitat Animal CReSA, Universitat Autònoma de Barcelona – Institut de Recerca i Tecnologia Agroalimentaries, Bellaterra, Spain
| | - David Solanes
- Centre de Recerca en Sanitat Animal CReSA, Universitat Autònoma de Barcelona – Institut de Recerca i Tecnologia Agroalimentaries, Bellaterra, Spain
| | - Joan Pujols
- Centre de Recerca en Sanitat Animal CReSA, Universitat Autònoma de Barcelona – Institut de Recerca i Tecnologia Agroalimentaries, Bellaterra, Spain
| | - Isabelle Schwartz-Cornil
- Virologie et Immunologie Moléculaires, Unité de Recherche UR892, Institut National de la Recherche Agronomique, Jouy-en-Josas, France
- * E-mail:
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9
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Prow NA, Tan CSE, Wang W, Hobson-Peters J, Kidd L, Barton A, Wright J, Hall RA, Bielefeldt-Ohmann H. Natural exposure of horses to mosquito-borne flaviviruses in south-east Queensland, Australia. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2013; 10:4432-43. [PMID: 24048209 PMCID: PMC3799510 DOI: 10.3390/ijerph10094432] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 08/05/2013] [Revised: 09/09/2013] [Accepted: 09/10/2013] [Indexed: 11/16/2022]
Abstract
In 2011 an unprecedented epidemic of equine encephalitis occurred in south-eastern (SE) Australia following heavy rainfall and severe flooding in the preceding 2–4 months. Less than 6% of the documented cases occurred in Queensland, prompting the question of pre-existing immunity in Queensland horses. A small-scale serological survey was conducted on horses residing in one of the severely flood-affected areas of SE-Queensland. Using a flavivirus-specific blocking-ELISA we found that 63% (39/62) of horses older than 3 years were positive for flavivirus antibodies, and of these 18% (7/38) had neutralizing antibodies to Murray Valley encephalitis virus (MVEV), Kunjin virus (WNVKUN) and/or Alfuy virus (ALFV). The remainder had serum-neutralizing antibodies to viruses in the Kokobera virus (KOKV) complex or antibodies to unknown/untested flaviviruses. Amongst eight yearlings one presented with clinical MVEV-encephalomyelitis, while another, clinically normal, had MVEV-neutralizing antibodies. The remaining six yearlings were flavivirus antibody negative. Of 19 foals born between August and November 2011 all were flavivirus antibody negative in January 2012. This suggests that horses in the area acquire over time active immunity to a range of flaviviruses. Nevertheless, the relatively infrequent seropositivity to MVEV, WNVKUN and ALFV (15%) suggests that factors other than pre-existing immunity may have contributed to the low incidence of arboviral disease in SE-Queensland horses during the 2011 epidemic.
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Affiliation(s)
- Natalie A. Prow
- Australian Infectious Diseases Research Centre, University of Queensland, St. Lucia, QLD 4078, Australia; E-Mails: (N.A.P.); (C.S.E.T.); (J.H.-P.); (R.A.H.)
- School of Biochemistry & Molecular Biosciences, University of Queensland, Brisbane, QLD 4072, Australia
| | - Cindy S. E. Tan
- Australian Infectious Diseases Research Centre, University of Queensland, St. Lucia, QLD 4078, Australia; E-Mails: (N.A.P.); (C.S.E.T.); (J.H.-P.); (R.A.H.)
- School of Biochemistry & Molecular Biosciences, University of Queensland, Brisbane, QLD 4072, Australia
| | - Wenqi Wang
- School of Veterinary Science, University of Queensland, Gatton, QLD 4343, Australia; E-Mails: (W.W.); (L.K.); (A.B.); (J.W.)
| | - Jody Hobson-Peters
- Australian Infectious Diseases Research Centre, University of Queensland, St. Lucia, QLD 4078, Australia; E-Mails: (N.A.P.); (C.S.E.T.); (J.H.-P.); (R.A.H.)
- School of Biochemistry & Molecular Biosciences, University of Queensland, Brisbane, QLD 4072, Australia
| | - Lisa Kidd
- School of Veterinary Science, University of Queensland, Gatton, QLD 4343, Australia; E-Mails: (W.W.); (L.K.); (A.B.); (J.W.)
| | - Anita Barton
- School of Veterinary Science, University of Queensland, Gatton, QLD 4343, Australia; E-Mails: (W.W.); (L.K.); (A.B.); (J.W.)
| | - John Wright
- School of Veterinary Science, University of Queensland, Gatton, QLD 4343, Australia; E-Mails: (W.W.); (L.K.); (A.B.); (J.W.)
| | - Roy A. Hall
- Australian Infectious Diseases Research Centre, University of Queensland, St. Lucia, QLD 4078, Australia; E-Mails: (N.A.P.); (C.S.E.T.); (J.H.-P.); (R.A.H.)
- School of Biochemistry & Molecular Biosciences, University of Queensland, Brisbane, QLD 4072, Australia
| | - Helle Bielefeldt-Ohmann
- Australian Infectious Diseases Research Centre, University of Queensland, St. Lucia, QLD 4078, Australia; E-Mails: (N.A.P.); (C.S.E.T.); (J.H.-P.); (R.A.H.)
- School of Veterinary Science, University of Queensland, Gatton, QLD 4343, Australia; E-Mails: (W.W.); (L.K.); (A.B.); (J.W.)
- Author to whom correspondence should be addressed; E-Mail: ; Tel.: +61-7-5460-1854; Fax: +61-7-5460-1922
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Nemeth N, Bosco-Lauth A, Oesterle P, Kohler D, Bowen R. North American birds as potential amplifying hosts of Japanese encephalitis virus. Am J Trop Med Hyg 2012; 87:760-7. [PMID: 22927494 DOI: 10.4269/ajtmh.2012.12-0141] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
Japanese encephalitis virus (JEV) is an emerging arbovirus, and inter-continental spread is an impending threat. The virus is maintained in a transmission cycle between mosquito vectors and vertebrate hosts, including birds. We detected variation in interspecies responses among North American birds to infection with strains of two different JEV genotypes (I and III). Several native North American passerine species and ring-billed gulls had the highest average peak viremia titers after inoculation with a Vietnamese (genotype I) JEV strain. Oral JEV shedding was minimal and cloacal shedding was rarely detected. The majority of birds, both viremic (72 of 74; 97.3%) and non-viremic (31 of 37; 83.8%), seroconverted by 14 days post-inoculation and West Nile virus-immune individuals had cross-protection against JEV viremia. Reservoir competence and serologic data for a variety of avian taxa are important for development of JEV surveillance and control strategies and will aid in understanding transmission ecology in the event of JEV expansion to North America.
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Affiliation(s)
- Nicole Nemeth
- Departments of Biomedical Sciences and Microbiology, Immunology, and Pathology, Colorado State University, Fort Collins, CO, USA.
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11
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Abstract
Huge emphasis has been placed on the role of the adaptive immune system in dengue pathogenesis. Yet there is increasing evidence for the importance of the innate immune system in regulating dengue infection and possibly influencing the disease. This review focuses on the interplay between the innate immune system and dengue and highlights the role of soluble immunological mediators. Type I and type II interferons of the innate immune system demonstrate non-overlapping roles in dengue infection. Furthermore, while some IFN responses to dengue are protective, others may exert disease-related effects on the host. But aside from interferons, a number of cytokines have also been implicated in dengue pathogenesis. Our expanding knowledge of cytokines indicates that these soluble mediators act upon a complicated network of events to provoke the disease. This cytokine storm is generally attributed to massive T cell activation as an outcome of secondary infection. However, there is reason to believe that innate immune response-derived cytokines also have contributory effects, especially in the context of severe cases of primary dengue infection. Another less popular but interesting perspective on dengue pathogenesis is the effect of mosquito feeding on host immune responses and viral infection. Various studies have shown that soluble factors from vector saliva have the capacity to alter immune reactions and thereby influence pathogen transmission and establishment. Hence, modulation of the innate immune system at various levels of infection is a critical component of dengue disease. In the absence of an approved drug or vaccine for dengue, soluble mediators of the innate immune system could be a strategic foothold for developing anti-viral therapeutics and improving clinical management.
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Affiliation(s)
- Lyre Anni Espada-Murao
- Department of Virology, Institute of Tropical Medicine, GCOE Programme, Nagasaki University, Sakamoto machi 1-12-4, Nagasaki 852-8523, Japan
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12
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Hahn DC, Reisen WK. Heightened Exposure to Parasites Favors the Evolution of Immunity in Brood Parasitic Cowbirds. Evol Biol 2011. [DOI: 10.1007/s11692-011-9112-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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13
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Abstract
West Nile virus (WNV) is transmitted to vertebrate hosts primarily by infected Culex mosquitoes. Transmission of arboviruses by the bite of infected mosquitoes can potentiate infection in hosts compared to viral infection by needle inoculation. Here we examined the effect of mosquito transmission on WNV infection and systematically investigated multiple factors that differ between mosquito infection and needle inoculation of WNV. We found that mice infected with WNV through the bite of a single infected Culex tarsalis mosquito exhibited 5- to 10-fold-higher viremia and tissue titers at 24 and 48 h postinoculation and faster neuroinvasion than mice given a median mosquito-inoculated dose of WNV (10(5) PFU) by needle. Mosquito-induced enhancement was not due to differences in inoculation location, because additional intravenous inoculation of WNV did not enhance viremia or tissue titers. Inoculation of WNV into a location where uninfected mosquitoes had fed resulted in enhanced viremia and tissue titers in mice similar to those in mice infected by a single infected mosquito bite, suggesting that differences in where virus is deposited in the skin and in the virus particle itself were not responsible for the enhanced early infection in mosquito-infected mice. In addition, inoculation of mice with WNV mixed with salivary gland extract (SGE) led to higher viremia, demonstrating that mosquito saliva is the major cause of mosquito-induced enhancement. Enhanced viremia was not observed when SGE was inoculated at a distal site, suggesting that SGE enhances WNV replication by exerting a local effect. Furthermore, enhancement of WNV infection still occurred in mice with antibodies against mosquito saliva. In conclusion, saliva from C. tarsalis is responsible for enhancement of early WNV infection in vertebrate hosts.
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Schneider BS, Higgs S. The enhancement of arbovirus transmission and disease by mosquito saliva is associated with modulation of the host immune response. Trans R Soc Trop Med Hyg 2008; 102:400-8. [PMID: 18342898 DOI: 10.1016/j.trstmh.2008.01.024] [Citation(s) in RCA: 171] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2007] [Revised: 01/29/2008] [Accepted: 01/31/2008] [Indexed: 01/23/2023] Open
Abstract
Arthropod-borne (arbo-) viruses have emerged as a major human health concern. Viruses transmitted by mosquitoes are the cause of the most serious and widespread arbovirus diseases worldwide and are ubiquitous in both feral and urban settings. Arboviruses, including dengue and West Nile virus, are injected into vertebrates within mosquito saliva during mosquito feeding. Mosquito saliva contains anti-haemostatic, anti-inflammatory and immunomodulatory molecules that facilitate the acquisition of a blood meal. Collectively, studies investigating the effects of mosquito saliva on the vertebrate immune response suggest that at high concentrations salivary proteins are immmunosuppressive, whereas lower concentrations modulate the immune response; specifically, T(H)1 and antiviral cytokines are downregulated, while T(H)2 cytokines are unaffected or amplified. As a consequence, mosquito saliva can impair the antiviral immune response, thus affecting viral infectiousness and host survival. Mounting evidence suggests that this is a mechanism whereby arbovirus pathogenicity is enhanced. In a range of disease models, including various hosts, mosquito species and arthropod-borne viruses, mosquito saliva and/or feeding is associated with a potentiation of virus infection. Compared with arbovirus infection initiated in the absence of the mosquito or its saliva, infection via mosquito saliva leads to an increase in virus transmission, host susceptibility, viraemia, disease progression and mortality.
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Affiliation(s)
- Bradley S Schneider
- Institut Pasteur, Département de Parasitologie, Unités de Réponses Précoces aux Parasites et Immunopathologie, 25 Rue du Docteur Roux, 75724 Paris Cedex 15, France.
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15
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Abstract
PURPOSE OF REVIEW West Nile virus emerged recently in North America as a serious human and animal pathogen. This review summarizes the use of experimental infections with West Nile virus in diverse vertebrate species that have been used to answer fundamental questions about the host response, pathogenesis of West Nile virus infection and virus evolution. RECENT FINDINGS West Nile virus has an extremely broad vertebrate host range. Infection of common species of birds has defined those with high vs. low potential to serve as amplifying hosts for the virus. In general, mammals (primates, horses, companion animals) are dead-end hosts for West Nile virus, although some circumstances (i.e. immunosuppression) may allow individuals to become capable of transmitting the virus to mosquitoes. Some mammals (rodents, rabbits, squirrels) and reptiles (alligators) have been found to develop a viremia of sufficient magnitude to predict at least low competence for infecting feeding mosquitoes. Finally, experimental infection of rodents, horses and primates with West Nile virus has been integral to developing and evaluating the efficacy of West Nile virus vaccines. SUMMARY Experimental infection with West Nile virus has assisted in delineating those hosts important and not important to the transmission cycle, in understanding how the virus induces disease in susceptible hosts, and in validating the efficacy of vaccines used for control of disease.
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Affiliation(s)
- Richard A Bowen
- Department of Biomedical Sciences, Colorado State University, Fort Collins, Colorado 80523, USA.
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16
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Reisen WK, Martinez VM, Fang Y, Garcia S, Ashtari S, Wheeler SS, Carroll BD. Role of California (Callipepla californica) and Gambel's (Callipepla gambelii) quail in the ecology of mosquito-borne encephalitis viruses in California, USA. Vector Borne Zoonotic Dis 2007; 6:248-60. [PMID: 16989564 DOI: 10.1089/vbz.2006.6.248] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Gambel's and California quail were infected repeatedly whenever western equine encephalomyelitis virus (WEEV), St. Louis encephalitis virus (SLEV), and (WNV) West Nile virus were active during summer in California. The timing of virus appearance and quail infection coincided well with the appearance of chicks in nature, leading us to hypothesize that large coveys containing these non-immune birds could be important in focal virus amplification in rural settings. However, experimental infection studies with chicks, juveniles, and adults of both quail species using sympatric strains of WEEV, SLEV, and WNV indicated that only immature birds were competent hosts for WEEV, producing viremias sufficiently elevated to efficiently infect Culex tarsalis mosquitoes. Quail were less competent hosts for WNV and were incompetent for SLEV. Large populations of quail that frequently are infected with SLEV or WNV, but produce low to moderate viremias, may serve as dead end hosts for these viruses. Due to their abundance and repeated infection, these birds may attenuate virus amplification in rural areas of California and possibly could be one reason why WNV epidemics seem to occur more frequently in urban and periurban than in rural landscapes.
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Affiliation(s)
- William K Reisen
- Center for Vectorborne Diseases, Department of Pathology, Microbiology and Immunology, School of Veterinary Medicine, University of California, Davis, California 95616, USA.
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17
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Reisen WK, Fang Y. Does feeding on infected mosquitoes (Diptera: Culicidae) enhance the role of song sparrows in the transmission of arboviruses in California? JOURNAL OF MEDICAL ENTOMOLOGY 2007; 44:316-9. [PMID: 17427703 DOI: 10.1603/0022-2585(2007)44[316:dfoimd]2.0.co;2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
Song sparrows, Melopiza melodia, inoculated subcutaneously with either western equine encephalomyelitis virus (family Togaviridae, genus Alphavirus, WEEV) or West Nile virus (family Flaviviridae, genus Flavivirus, WNV) developed elevated viremias, and they were considered to be competent experimental hosts for both viruses. However, birds that ingested from three to 20 mosquitoes containing comparable amounts of either WEEV or WNV failed to become infected, indicating limited oral susceptibility. Comparatively few field-collected birds had antibodies against either WEEV or WNV, indicating that this species was infrequently bitten by infectious mosquitoes in nature and probably was of limited importance in viral amplification.
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Affiliation(s)
- William K Reisen
- Center for Vectorborne Diseases and Department of Pathology, Microbiology, and Immunology, School of Veterinary Medicine, University of California, Davis, CA 95616, USA.
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18
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Smith DR, Aguilar PV, Coffey LL, Gromowski GD, Wang E, Weaver SC. Venezuelan equine encephalitis virus transmission and effect on pathogenesis. Emerg Infect Dis 2006; 12:1190-6. [PMID: 16965696 PMCID: PMC3291203 DOI: 10.3201/eid1708.050841] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Quantifying the dose of an arbovirus transmitted by mosquitoes is essential for designing pathogenesis studies simulating natural infection of vertebrates. Titration of saliva collected in vitro from infected mosquitoes may not accurately estimate titers transmitted during blood feeding, and infection by needle injection may affect vertebrate pathogenesis. We compared the amount of Venezuelan equine encephalitis virus collected from the saliva of Aedes taeniorhynchus to the amount injected into a mouse during blood feeding. Less virus was transmitted by mosquitoes in vivo (geometric mean 11 PFU) than was found for comparable times of salivation in vitro (mean saliva titer 74 PFU). We also observed slightly lower early and late viremia titers in mice that were needle injected with 8 PFU, which represents the low end of the in vivo transmission range. No differences in survival were detected, regardless of the dose or infection route.
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Affiliation(s)
- Darci R. Smith
- University of Texas Medical Branch, Galveston, Texas, USA
| | | | - Lark L. Coffey
- University of Texas Medical Branch, Galveston, Texas, USA
| | | | - Eryu Wang
- University of Texas Medical Branch, Galveston, Texas, USA
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19
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Smith DR, Aguilar PV, Coffey LL, Gromowski GD, Wang E, Weaver SC. Venezuelan equine encephalitis virus transmission and effect on pathogenesis. Emerg Infect Dis 2006; 12. [PMID: 16965696 PMCID: PMC3291203 DOI: 10.3201/eid1208.050841] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Quantifying the dose of an arbovirus transmitted by mosquitoes is essential for designing pathogenesis studies simulating natural infection of vertebrates. Titration of saliva collected in vitro from infected mosquitoes may not accurately estimate titers transmitted during blood feeding, and infection by needle injection may affect vertebrate pathogenesis. We compared the amount of Venezuelan equine encephalitis virus collected from the saliva of Aedes taeniorhynchus to the amount injected into a mouse during blood feeding. Less virus was transmitted by mosquitoes in vivo (geometric mean 11 PFU) than was found for comparable times of salivation in vitro (mean saliva titer 74 PFU). We also observed slightly lower early and late viremia titers in mice that were needle injected with 8 PFU, which represents the low end of the in vivo transmission range. No differences in survival were detected, regardless of the dose or infection route.
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Affiliation(s)
- Darci R. Smith
- University of Texas Medical Branch, Galveston, Texas, USA
| | | | - Lark L. Coffey
- University of Texas Medical Branch, Galveston, Texas, USA
| | | | - Eryu Wang
- University of Texas Medical Branch, Galveston, Texas, USA
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20
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Schneider BS, Soong L, Girard YA, Campbell G, Mason P, Higgs S. Potentiation of West Nile encephalitis by mosquito feeding. Viral Immunol 2006; 19:74-82. [PMID: 16553552 DOI: 10.1089/vim.2006.19.74] [Citation(s) in RCA: 104] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Mosquitoes infect human beings with arboviruses while taking a blood meal, inoculating virus with their saliva. Mosquito saliva contains compounds that counter host hemostatic, inflammatory, and immune responses. Modulation of these crucial defensive responses may facilitate virus infection. Using a murine model we explored the potential for mosquitoes to impact the course of West Nile virus (WNV) disease by determining whether differences in pathogenesis occurred in the presence or absence of mosquito saliva. Mice inoculated intradermally with 10(4) pfu of WNV subsequent to the feeding of mosquitoes developed more progressive infection, higher viremia, and accelerated neuroinvasion than the mice inoculated with WNV alone. At a lower dose of WNV (10(2) pfu), mice fed upon by mosquitoes had a lower survival rate. This study suggests that mosquito feeding and factors in mosquito saliva can potentiate WNV infection, and offers a possible mechanism for this effect via accelerated infection of the brain.
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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 77555-0609, USA
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21
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Mahmood F, Chiles RE, Fang Y, Green EN, Reisen WK. Effects of time after infection, mosquito genotype, and infectious viral dose on the dynamics of Culex tarsalis vector competence for western equine encephalomyelitis virus. JOURNAL OF THE AMERICAN MOSQUITO CONTROL ASSOCIATION 2006; 22:272-81. [PMID: 17019773 DOI: 10.2987/8756-971x(2006)22[272:eotaim]2.0.co;2] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
The vector competence of Culex tarsalis Coquillett for the BFS 1703 strain of western equine encephalomyelitis virus (WEEV) changed significantly as a function of time after infection, mosquito genotype, and infectious virus dose. After ingesting a high virus dose (5 log10 plaque-forming units [PFU]/0.1 ml), female of the susceptible high virus producer (HVP) strain rapidly amplified the virus, developed a disseminated infection, and efficiently transmitted WEEV by 4 days postinfection (dpi). The quantity of virus expectorated peaked at 4 dpi (mean 3.4 log10 PFU), and the percentage of females transmitting per os peaked at 7 dpi (80%); both measures of transmission subsequently decreased to low levels throughout the remainder of infected life. HVP females imbibing a low virus dose (3 log10 PFU/0.1 ml) were infected less frequently and took longer to amplify virus to levels recorded for the high virus dose group and did not transmit virus efficiently, thereby indicating midgut infection and escape barriers were dose and time dependent. These data emphasized the importance of elevated avian viremias in Cx. tarsalis vector competence. Females from the WEEV-resistant (WR) strain and two wild-type strains from Kern and Riverside counties were significantly less susceptible to infection at both high and low doses than was the HVP strain. Overall, females with a high virus titer more frequently had a disseminated infection, but there did not seem to be a distinct threshold demarcating this relationship. In marked contrast, all infected females transmitting virus had body titers >4.3 log10 PFU, and most had titers >4.8 log10 PFU. These data indicated that not all females with a disseminated infection transmitted virus because of the presence of one or more salivary gland barriers.
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Affiliation(s)
- Farida Mahmood
- Arbovirus Laboratory, Center for Vectorborne Diseases, Department of Pathology, Microbiology, and Immunology, School of Veterinary Medicine, University of California, Old Davis Road, Davis, CA 95616, USA
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22
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Colton L, Biggerstaff BJ, Johnson A, Nasci RS. Quantification of West Nile virus in vector mosquito saliva. JOURNAL OF THE AMERICAN MOSQUITO CONTROL ASSOCIATION 2005; 21:49-53. [PMID: 15825761 DOI: 10.2987/8756-971x(2005)21[49:qownvi]2.0.co;2] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Saliva was collected from 4 species of mosquitoes intrathoracically inoculated with West Nile virus (WNV). The amount of infectious virus in the saliva was quantified by plaque assay and the number of WNV genomic equivalents (GE) was measured by reverse transcriptase-polymerase chain reaction. Ochlerotatus triseriatus had the greatest mean amount of infectious virus per saliva collection, followed by Aedes albopictus, Culex pipiens, and Cx. quinquefasciatus. The mean GE/saliva collection was also greatest in Oc. triseriatus, followed by Cx. quinquefasciatus, Cx. pipiens, and Ae. albopictus. The variance of log GE/saliva collection for Ae. albopictus was significantly lower than the variance for the other 3 species. This study provides a basis for comparing this component of vector competence and for determining the amounts of virus inoculated into vertebrates in experimental host competence studies.
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Affiliation(s)
- Leah Colton
- Centers for Disease Control and Prevention, Division of Vector-Borne Infectious Diseases, PO Box 2087, Fort Collins, CO 80522, USA
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23
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Reisen WK, Chiles R, Martinez V, Fang Y, Green E, Clark S. Effect of dose on house finch infection with western equine encephalomyelitis and St. Louis encephalitis viruses. JOURNAL OF MEDICAL ENTOMOLOGY 2004; 41:978-981. [PMID: 15535631 DOI: 10.1603/0022-2585-41.5.978] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
House finches, Carpodacus mexicanus, were experimentally infected with high and standard doses of western equine encephalomyelitis virus (WEEV) or St. Louis encephalitis virus (SLEV) to determine whether high doses would produce an elevated viremia response and a high frequency of chronic infections. Finches inoculated with approximately100,000 plaque forming units (PFU) of WEEV or SLEV produced viremia and antibody responses similar to those in finches inoculated with approximately 100 PFU of WEEV or 1000 PFU of SLEV, the approximate quantities of virus expectorated by blood-feeding Culex tarsalis Coquillett. Infected finches were held through winter and then necropsied. Only one finch inoculated with the high dose of SLEV developed a chronic infection. Our data indicated that elevated infectious doses of virus may not increase the viremia level or the frequency of chronic infection in house finches.
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Affiliation(s)
- William K Reisen
- Center for Vectorborne Diseases, School of Veterinary Medicine, University of California, Davis, CA 95616, USA
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24
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Mahmood F, Chiles RE, Fang Y, Barker CM, Reisen WK. Role of nestling mourning doves and house finches as amplifying hosts of St. Louis encephalitis virus. JOURNAL OF MEDICAL ENTOMOLOGY 2004; 41:965-972. [PMID: 15535629 DOI: 10.1603/0022-2585-41.5.965] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Nestling mourning doves and house finches produced elevated viremias after inoculation with 2-3 log10 plaque-forming units (PFU) of St Louis encephalitis (SLE) virus and infected 67 and 70% of Culex tarsalis Coquillett that engorged upon them, respectively. Mosquito infection rates as well as the quantity of virus produced after extrinsic incubation increased as a function of the quantity of virus ingested and peaked during days 3-5 postinoculation in mourning doves and days 2-4 in house finches. Only female Cx. tarsalis with body titers > or = 4.6 log10 PFU were capable of transmitting virus. Overall, 38% of females infected by feeding on mourning doves and 22% feeding on house finches were capable of transmission. The quantity of virus expectorated was variable, ranging from 0.8 to 3.4 log10 PFU and was greatest during periods when avian viremias were elevated. Our data indicated that nestling mourning doves and house finches were competent hosts for SLE virus and that the quantity of virus ingested from a viremic avian host varies during the course of the infection and determines transmission rates by the mosquito vector.
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Affiliation(s)
- Farida Mahmood
- Center for Vectorborne Diseases, School of Veterinary Medicine, Old Davis Road, University of California, Davis, California 95616, USA
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25
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Reisen WK, Chiles RE, Martinez VM, Fang Y, Green EN. Encephalitis virus persistence in California birds: experimental infections in mourning doves (Zenaidura macroura). JOURNAL OF MEDICAL ENTOMOLOGY 2004; 41:462-466. [PMID: 15185951 DOI: 10.1603/0022-2585-41.3.462] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
After-hatching and hatching year, mourning doves were infected by inoculation with either western equine encephalomyelitis (WEE) or St. Louis encephalitis (SLE) viruses; some birds in each group also were treated with the immunosuppressant cyclophosphamide before and during infection. Cyclophosphamide treatment significantly increased the WEE viremia but did not alterthe antibody response. In contrast, cyclophosphamide-treated and -untreated doves did not develop a detectable SLE viremia but became antibody positive. Antibody peaked at 10 wk after inoculation for both viruses and remained detectable in most birds throughout the 26-wk study. When treated with cyclophosphamide the following spring, birds did not relapse and develop a detectable viremia. Previously infected birds were protected when challenged with conspecific virus (i.e., none produced a detectable viremia), but there was no anamnestic antibody response to reinfection. In agreement with our failure to detect relapses, all birds were negative for viral RNA when sera, spleen, lung, and kidney tissues were tested by reverse transcriptase-polymerase chain reaction after necropsy. Our results indicated that adult mourning doves were an incompetent host for SLE virus and probably do not serve as a suitable overwintering or dispersal host for either WEE and SLE viruses.
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Affiliation(s)
- William K Reisen
- Center for Vectorborne Diseases, School of Veterinary Medicine, Davis, University of California, CA 95616, USA.
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26
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Reisen WK, Chiles RE, Martinez VM, Fang Y, Green EN. Experimental infection of California birds with western equine encephalomyelitis and St. Louis encephalitis viruses. JOURNAL OF MEDICAL ENTOMOLOGY 2003; 40:968-982. [PMID: 14765678 DOI: 10.1603/0022-2585-40.6.968] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
A total of 27 bird species from the San Joaquin and Coachella valleys of California were inoculated subcutaneously with sympatric strains of western equine encephalomyelitis (WEE) and St. Louis encephalitis (SLE) viruses. Overall, 133 of 164 birds inoculated with WEE virus developed a viremia detected by plaque assay; significantly greater than 72 of 163 birds inoculated with SLE virus. Host competence was calculated as the average number of days that each avian species had a viremia > or = 2 log10 plaque-forming units per 0.1 ml, the threshold for infecting susceptible Culex tarsalis Coquillett, the primary vector of these viruses in California. Eleven of 20 species inoculated with WEE virus had a value > or = 1 and were considered to be competent hosts, whereas only six of 22 species inoculated with SLE virus had a value > or = 1. Overall, 133 of 164 birds inoculated with WEE virus and 105 of 163 inoculated with SLE virus produced antibody detectable by enzyme immunoassay and/or plaque reduction neutralization test. Six birds infected with WEE virus (one house finch, three mourning doves, one Brewer's sparrow, and one white-crowned sparrow) and nine birds infected with SLE virus (two house finches, three white-crowned sparrows, one song sparrow, two Western scrub-jays, and one orange crowned warbler) contained viral RNA detected by reverse transcription-polymerase chain reaction at necropsy > 6 wk postinoculation; infectious WEE and SLE viruses were only recovered from three mourning doves and an orange-crowned warbler, respectively, after blind passage in mosquito cells. Our study indicated that birds with elevated field antibody prevalence rates may not be the most competent hosts for encephalitis viruses and that relatively few birds developed chronic infections that could be important in virus persistence and dispersal.
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Affiliation(s)
- W K Reisen
- Center for Vectorborne Diseases, School of Veterinary Medicine, University of California, Old Davis Road, Davis, CA 95616, USA.
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27
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Reisen WK, Chiles RE, Green EN, Fang Y, Mahmood F. Previous infection protects house finches from re-infection with St. Louis encephalitis virus. JOURNAL OF MEDICAL ENTOMOLOGY 2003; 40:300-305. [PMID: 12943108 DOI: 10.1603/0022-2585-40.3.300] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Antibody titers against St. Louis encephalitis virus (SLE) measured by a plaque reduction neutralization test (PRNT) decreased rapidly in house finches (Capodacus mexicanus) after initial infection, whereas antibodies measured by enzyme immunoassay (EIA) remained detectable in all birds for the length of the experiment, indicating long-term persistence and greater assay sensitivity of the EIA. After 52 wk, birds were challenged by subcutaneous inoculation with the same strain of SLE virus. Virus was not detected for 1-4 d postchallenge in blood samples tested by plaque assay and RT-PCR or by xenodiagnosis in Culex tarsalis fed concurrently and then held for 11 d at 26 degrees C. Virus was detected by all three methods in control birds infected concurrently for the first time. Challenge with SLE produced a rapid and marked ananmestic rise in both neutralizing and EIA antibody titers that exceeded the primary response in the same birds or in concurrently inoculated control birds. At necropsy 4 wk postchallenge, 3 of 7 challenged and 1 of 2 positive control birds were chronically infected, with viral RNA detected by RT-PCR in brain, spleen, lung, and/or kidney tissues. Our results indicated that persistence of protective antibody prevents reinfection during the following season and may prevent the recrudescence of infectious virus in chronically infected birds.
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Affiliation(s)
- W K Reisen
- Arbovirus Research Unit, Center for Vector borne Diseases, School of Veterinary Medicine, University of California, Davis 95616, USA.
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28
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Reisen WK, Chiles RE, Green EN, Fang Y, Mahmood F, Martinez VM, Laver T. Effects of immunosuppression on encephalitis virus infection in the house finch, Carpodacus mexicanus. JOURNAL OF MEDICAL ENTOMOLOGY 2003; 40:206-214. [PMID: 12693850 DOI: 10.1603/0022-2585-40.2.206] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Immunosuppression of house finches was attempted by blood feeding Culex tarsalis Coquillett mosquitoes or by injecting birds with the corticosteroid dexamethasone or the immunosuppressant drug cyclophosphamide before and after inoculation with western equine encephalomyelitis or St. Louis encephalitis viruses. Mosquito bites (8-37 females blood feeding on each bird over a 3-d period) did not enhance the viremia response or increase the frequency of chronic infection. In contrast, dexamethasone and cyclophosphamide enhanced the amplitude and duration of the viremia response, but had no consistent effect on the antibody responses as measured by enzyme immunoassay or plaque reduction neutralization assay. Elevated viremias were followed by increases in the frequency of chronic infections with St. Louis encephalitis, but not western equine encephalomyelitis. Immunosuppression may provide a useful tool to study the chronic infection process of flaviviruses in vertebrates.
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Affiliation(s)
- William K Reisen
- Arbovirus Research Unit, Center for Vector-borne Disease Research, School of Veterinary Medicine, University of California, Davis, CA 95616, USA.
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Abstract
By combining molecular-biological techniques with our increased understanding of the effect of gene sequence modification on viral function, yellow fever 17D, a positive-strand RNA virus vaccine, has been manipulated to induce a protective immune response against viruses of the same family (e.g. Japanese encephalitis and dengue viruses). Triggered by the emergence of West Nile virus infections in the New World afflicting humans, horses and birds, the success of this recombinant technology has prompted the rapid development of a live-virus attenuated candidate vaccine against West Nile virus.
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Affiliation(s)
- J Arroyo
- Acambis Inc. 38 Sidney Street, Cambridge, MA 02319, USA.
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30
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Reisen WK, Kramer LD, Chiles RE, Green EG, Martinez VM. Encephalitis virus persistence in California birds: preliminary studies with house finches. JOURNAL OF MEDICAL ENTOMOLOGY 2001; 38:393-399. [PMID: 11372964 DOI: 10.1603/0022-2585-38.3.393] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Field-collected house finches of mixed sex and age were infected experimentally with either western equine encephalomyelitis (WEE) or St. Louis encephalitis (SLE) viruses during the summer or fall of 1998 and maintained over the winter under ambient conditions. To detect natural relapse during the spring, 32 birds were bled weekly from February through June 1999, and then necropsied 1 yr after infection to detect chronic infections using a reverse transcription polymerase chain reaction (RT-PCR). After 10 mo, 13/14 surviving birds previously infected with WEE were antibody positive by enzyme immunoassay (EIA), and 11/14 had plaque reduction neutralization test (PRNT) antibody titers >1:20, whereas only of 8/13 birds previously infected with SLE were positive by EIA and all had PRNT titers <1:20. When necropsied, 1/14 and 1/13 birds had WEE and SLE RT-PCR positive lung or spleen tissue, respectively; blood, brain, and liver tissues were negative as were all previous blood samples. All tissues from these birds including weekly blood samples tested negative for infectious virus by plaque assay on Vero cell culture. To determine if persistent antibody was protective, birds infected initially with WEE or SLE in November 1998 were challenged 6 mo later with homologous virus. WEE antibody persisted well (5/6 birds remained PRNT positive before challenge) and remained protective, because 0/6 birds were viremic after challenge. In contrast, SLE antibody decayed rapidly (0/6 birds remained PRNT positive before challenge) and was not protective, because 3/6 birds developed an ephemeral viremia on day 1 after infection (mean titer, 10(2.73) plaque forming units/0.1 ml). When necropsied 7 wk after challenge, 1/110 birds infected with WEE and 1/10 birds infected with SLE exhibited an RT-PCR positive spleen, despite the fact that both birds had PRNT antibody titers >1:40 at this time. To determine if immunosuppression would cause a chronic infection to relapse, eight birds initially infected with either WEE or SLE were treated with cyclophosphamide and then tested repeatedly for viremia; all samples were negative for virus by plaque assay. Collectively, our results indicated that a low percentage of birds experimentally infected with WEE or SLE developed chronic infections in the spleen or lung that could be detected by RT-PCR, but not by plaque assay. Birds did not appear to relapse naturally or after immunosuppression. The rapid decay of SLE, but not WEE, antibody may allow the relapse of chronic infections of SLE, but not WEE, to produce viremias sufficiently elevated to infect mosquitoes.
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Affiliation(s)
- W K Reisen
- Arbovirus Research Unit, Center for Vector-borne Disease Research, School of Veterinary Medicine, University of California, Davis 95616, USA
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Reisen WK, Lundstrom JO, Scott TW, Eldridge BF, Chiles RE, Cusack R, Martinez VM, Lothrop HD, Gutierrez D, Wright SE, Boyce K, Hill BR. Patterns of avian seroprevalence to western equine encephalomyelitis and Saint Louis encephalitis viruses in California, USA. JOURNAL OF MEDICAL ENTOMOLOGY 2000; 37:507-527. [PMID: 10916291 DOI: 10.1603/0022-2585-37.4.507] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Temporal and spatial changes in the enzootic activity of western equine encephalomyelitis (WEE) and St. Louis encephalitis (SLE) viruses were monitored at representative wetland study sites in the Coachella, San Joaquin, and Sacramento valleys of California from 1996 to 1998 using three methods: (1) virus isolation from pools of 50 host-seeking Culex tarsalis Coquillett females, (2) seroconversions in flocks of 10 sentinel chickens, and (3) seroprevalence in wild birds collected by mist nets and grain baited traps. Overall, 74 WEE and one SLE isolates were obtained from 222,455 Cx. tarsalis females tested in 4,988 pools. In addition, 133 and 40 seroconversions were detected in 28 chicken flocks, and 143 and 27 of 20,192 sera tested from 149 species of wild birds were positive for antibodies to WEE and SLE, respectively. WEE was active in all three valleys, whereas SLE only was detected in Coachella Valley. Seroconversions in sentinel chickens provided the most sensitive indication of enzootic activity and were correlated with seroprevalence rates in wild birds. Avian seroprevalence rates did not provide an early warning of pending enzootic activity in chickens, because positive sera from after hatching year birds collected during spring most probably were the result of infections acquired during the previous season. Few seroconversions were detected among banded recaptured birds collected during spring and early summer. Age and resident status, but not sex, were significant risk factors for wild bird infection, with the highest seroprevalence rates among after hatching year individuals of permanent resident species. Migrants (with the exception of mourning doves) and winter resident species rarely were positive. House finches, house sparrows, Gambel's quail, California quail, common ground doves, and mourning doves were most frequently positive for antibodies. The initial detection of enzootic activity each summer coincided closely with the appearance of hatching year birds of these species in our study areas, perhaps indicating their role in virus amplification. Bird species most frequently positive roosted or nested in elevated upland vegetation, sites where Cx. tarsalis host-seeking females hunt most frequently. These serosurveys provided important background information for planned host competence and chronic infection studies.
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MESH Headings
- Animals
- Animals, Wild
- Bird Diseases/epidemiology
- Bird Diseases/immunology
- Bird Diseases/virology
- Birds/virology
- California/epidemiology
- Chickens
- Culex/virology
- Encephalitis Virus, St. Louis/immunology
- Encephalitis Virus, St. Louis/isolation & purification
- Encephalitis Virus, Western Equine/immunology
- Encephalitis Virus, Western Equine/isolation & purification
- Encephalitis, St. Louis/immunology
- Encephalitis, St. Louis/veterinary
- Encephalitis, St. Louis/virology
- Encephalomyelitis, Equine/epidemiology
- Encephalomyelitis, Equine/immunology
- Encephalomyelitis, Equine/veterinary
- Encephalomyelitis, Equine/virology
- Female
- Seroepidemiologic Studies
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Affiliation(s)
- W K Reisen
- Arbovirus Research Unit, School of Veterinary Medicine, University of California, Davis 95616, USA
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Reisen WK, Kramer LD, Chiles RE, Martinez VM, Eldridge BF. Response of house finches to infection with sympatric and allopatric strains of western equine encephalomyelitis and St. Louis encephalitis viruses from California. JOURNAL OF MEDICAL ENTOMOLOGY 2000; 37:259-264. [PMID: 10730497 DOI: 10.1603/0022-2585-37.2.259] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Adult house finches from Kern County were inoculated subcutaneously with recent sympatric and allopatric isolates of western equine encephalomyelitis and St. Louis encephalitis (SLE) viruses made from Culex tarsalis Coquillett collected in Kern County and Coachella Valley, CA, respectively. Virulence, as measured by the amplitude of the viremia response during days 1 and 2 postinfection, varied significantly among strains, but independently of geographic origin. The intensity of the immune response, as measured by an enzyme immunoassay and a plaque reduction neutralization test, seemed to be independent of virulence, especially for SLE where some strains failed to produce a detectable viremia but elicited a strong antibody response. Our preliminary data indicated that strain virulence may be associated with the level of enzootic activity during the year of isolation.
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MESH Headings
- Animals
- Antibodies, Viral/immunology
- Bird Diseases/immunology
- Bird Diseases/virology
- California
- Culex/virology
- Encephalitis Virus, St. Louis/immunology
- Encephalitis Virus, St. Louis/pathogenicity
- Encephalitis Virus, Western Equine/immunology
- Encephalitis Virus, Western Equine/pathogenicity
- Encephalitis, St. Louis/immunology
- Encephalitis, St. Louis/veterinary
- Encephalitis, St. Louis/virology
- Encephalomyelitis, Equine/immunology
- Encephalomyelitis, Equine/veterinary
- Encephalomyelitis, Equine/virology
- Humans
- Songbirds
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Affiliation(s)
- W K Reisen
- Arbovirus Research Unit, School of Veterinary Medicine, University of California, Davis, USA
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