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Luethy D. Eastern, Western, and Venezuelan Equine Encephalitis and West Nile Viruses: Clinical and Public Health Considerations. Vet Clin North Am Equine Pract 2023; 39:99-113. [PMID: 36737290 DOI: 10.1016/j.cveq.2022.11.007] [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] [Indexed: 02/05/2023] Open
Abstract
The continued recognition and emergence of alphavirus and flavivirus diseases is a growing veterinary and public health concern. As the global environment continues to change, mosquito-borne diseases will continue to evolve and expand. Continued development of readily available vaccines for the prevention of these diseases in humans and animals is essential to controlling epizootics of these diseases. Further research into effective antiviral treatments is also sorely needed. This article describes equine encephalitis viruses with a focus on clinical and public health considerations.
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Affiliation(s)
- Daniela Luethy
- Large Animal Internal Medicine, Large Animal Clinical Sciences, College of Veterinary Medicine, University of Florida, PO Box 100136, Gainesville, FL 32610, USA.
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Reyna RA, Weaver SC. Sequelae and Animal Modeling of Encephalitic Alphavirus Infections. Viruses 2023; 15:v15020382. [PMID: 36851596 PMCID: PMC9959775 DOI: 10.3390/v15020382] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2022] [Revised: 01/25/2023] [Accepted: 01/27/2023] [Indexed: 01/31/2023] Open
Abstract
Eastern (EEEV), Venezuelan (VEEV), and western equine encephalitis viruses (WEEV) are members of the genus Alphavirus, family Togaviridae. Typically spread by mosquitoes, EEEV, VEEV, and WEEV induce febrile illness that may develop into more severe encephalitic disease, resulting in myriad severe neurologic sequelae for which there are no vaccines or therapeutics. Here, we summarize the clinical neurologic findings and sequelae induced by these three encephalitic viruses and describe the various animal models available to study them. We emphasize the crucial need for the development of advanced animal modeling combined with the use of telemetry, behavioral testing, and neuroimaging to facilitate a detailed mechanistic understanding of these encephalitic signs and sequelae. Through the use of these systems, much-needed therapeutics and vaccines can be developed.
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Affiliation(s)
- Rachel A. Reyna
- Department of Pathology, University of Texas Medical Branch, Galveston, TX 77555, USA
| | - Scott C. Weaver
- Department of Pathology, 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
- Correspondence:
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Kehn-Hall K, Bradfute SB. Understanding host responses to equine encephalitis virus infection: implications for therapeutic development. Expert Rev Anti Infect Ther 2022; 20:1551-1566. [PMID: 36305549 DOI: 10.1080/14787210.2022.2141224] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
INTRODUCTION Venezuelan, eastern, and western equine encephalitis viruses (VEEV, EEEV, and WEEV) are mosquito-borne New World alphaviruses that cause encephalitis in equids and humans. These viruses can cause severe disease and death, as well as long-term severe neurological symptoms in survivors. Despite the pathogenesis and weaponization of these viruses, there are no approved therapeutics for treating infection. AREAS COVERED In this review, we describe the molecular pathogenesis of these viruses, discuss host-pathogen interactions needed for viral replication, and highlight new avenues for drug development with a focus on host-targeted approaches. EXPERT OPINION Current approaches have yielded some promising therapeutics, but additional emphasis should be placed on advanced development of existing small molecules and pursuit of pan-encephalitic alphavirus drugs. More research should be conducted on EEEV and WEEV, given their high lethality rates.
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Affiliation(s)
- Kylene Kehn-Hall
- Department of Biomedical Sciences and Pathobiology, Virginia-Maryland College of Veterinary Medicine, Virginia Tech, Blacksburg, VA, USA.,Center for Emerging, Zoonotic, and Arthropod-borne Pathogens, Virginia Tech, Blacksburg, VA, USA
| | - Steven B Bradfute
- Department of Internal Medicine, University of New Mexico Health Sciences Center, Albuquerque, NM, USA
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Knox A, Beddoe T. Isothermal Nucleic Acid Amplification Technologies for the Detection of Equine Viral Pathogens. Animals (Basel) 2021; 11:ani11072150. [PMID: 34359278 PMCID: PMC8300645 DOI: 10.3390/ani11072150] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Revised: 07/17/2021] [Accepted: 07/18/2021] [Indexed: 01/25/2023] Open
Abstract
Simple Summary Equine viral diseases remain a prominent concern for human and equine health globally. Many of these viruses are of primary biosecurity concern to countries that import equines where these viruses are not present. In addition, several equine viruses are zoonotic, which can have a significant impact on human health. Current diagnostic techniques are both time consuming and laboratory-based. The ability to accurately detect diseases will lead to better management, treatment strategies, and health outcomes. This review outlines the current modern isothermal techniques for diagnostics, such as loop-mediated isothermal amplification and insulated isothermal polymerase chain reaction, and their application as point-of-care diagnostics for the equine industry. Abstract The global equine industry provides significant economic contributions worldwide, producing approximately USD $300 billion annually. However, with the continuous national and international movement and importation of horses, there is an ongoing threat of a viral outbreak causing large epidemics and subsequent significant economic losses. Additionally, horses serve as a host for several zoonotic diseases that could cause significant human health problems. The ability to rapidly diagnose equine viral diseases early could lead to better management, treatment, and biosecurity strategies. Current serological and molecular methods cannot be field-deployable and are not suitable for resource-poor laboratories due to the requirement of expensive equipment and trained personnel. Recently, isothermal nucleic acid amplification technologies, such as loop-mediated isothermal amplification (LAMP) and insulated isothermal polymerase chain reaction (iiPCR), have been developed to be utilized in-field, and provide rapid results within an hour. We will review current isothermal diagnostic techniques available to diagnose equine viruses of biosecurity and zoonotic concern and provide insight into their potential for in-field deployment.
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Keshtkar-Jahromi M, Reisler RB, Haller JM, Clizbe DP, Rivard RG, Cardile AP, Pierson BC, Norris S, Saunders D, Pittman PR. The Western Equine Encephalitis Lyophilized, Inactivated Vaccine: An Update on Safety and Immunogenicity. Front Immunol 2020; 11:555464. [PMID: 33240257 PMCID: PMC7680781 DOI: 10.3389/fimmu.2020.555464] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2020] [Accepted: 09/24/2020] [Indexed: 11/13/2022] Open
Abstract
Background Western Equine Encephalitis (WEE) is a naturally acquired infection and potentially devastating bioweapon, with no specific human countermeasures. An experimental inactivated Western Equine Encephalitis Vaccine (WEEV; WEE TSI-GSD 210) has been used under an IND (investigational New Drug) protocol at the United States Army Medical Research Institute of Infectious Diseases (USAMRIID) since 1976. Methods Over 24 years from 1987 to 2011, 876 subjects received 3 primary vaccine doses under 3 studies with 1,537 booster doses administered (FY87-8, phase 2, laboratory workers, vaccine lots 1-81-1, 1-81-2, and 2-1-91; FY99-12, phase 2 laboratory workers, lot 2-1-91; and FY09-02, phase 1 healthy volunteer, lot 3-1-92). Post-vaccination safety and immunogenicity [plaque reduction neutralization test 80% (PRNT80) > 1:40] were analyzed. Results Overall PRNT80 response to the primary series in FY87-8 was 42% (326/770) but dropped to 16% (14/87) in FY99-12, prompting study FY09-02, which achieved 89% (17/19). The first booster response rate was 68% (814/1194) in FY87-8, 53% (171/324) in FY99-12, and 100% (10/10) in FY09-02. The majority of definitely related adverse reactions (AEs) were mild and local with no definitely related serious AEs. No laboratory acquired WEE infection was documented during this period despite 4 reported exposures in vaccinated subjects. Conclusion The TSI-GSD 210 WEE vaccine was immunogenic, safe and well tolerated. Use of this vaccine could be considered in an emergency setting. Despite decades of safe and effective use under IND, full licensure is not planned due to manufacturing constraints, and a strategic decision to develop alternatives. Clinical Trial Registration https://clinicaltrials.gov/, identifier NCT01159561.
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Affiliation(s)
- Maryam Keshtkar-Jahromi
- Division of Infectious Diseases, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, United States
| | - Ronald B Reisler
- Division of Medicine, United States Army Medical Research Institute of Infectious Diseases, Fort Detrick, MD, United States
| | - Jeannine M Haller
- Division of Medicine, United States Army Medical Research Institute of Infectious Diseases, Fort Detrick, MD, United States
| | - Denise P Clizbe
- Division of Medicine, United States Army Medical Research Institute of Infectious Diseases, Fort Detrick, MD, United States
| | - Robert G Rivard
- Division of Medicine, United States Army Medical Research Institute of Infectious Diseases, Fort Detrick, MD, United States
| | - Anthony P Cardile
- Division of Medicine, United States Army Medical Research Institute of Infectious Diseases, Fort Detrick, MD, United States
| | - Benjamin C Pierson
- Division of Medicine, United States Army Medical Research Institute of Infectious Diseases, Fort Detrick, MD, United States
| | - Sarah Norris
- Division of Medicine, United States Army Medical Research Institute of Infectious Diseases, Fort Detrick, MD, United States
| | - David Saunders
- Division of Medicine, United States Army Medical Research Institute of Infectious Diseases, Fort Detrick, MD, United States
| | - Phillip R Pittman
- Division of Medicine, United States Army Medical Research Institute of Infectious Diseases, Fort Detrick, MD, United States
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Azar SR, Campos RK, Bergren NA, Camargos VN, Rossi SL. Epidemic Alphaviruses: Ecology, Emergence and Outbreaks. Microorganisms 2020; 8:E1167. [PMID: 32752150 PMCID: PMC7464724 DOI: 10.3390/microorganisms8081167] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2020] [Revised: 07/23/2020] [Accepted: 07/28/2020] [Indexed: 12/13/2022] Open
Abstract
Over the past century, the emergence/reemergence of arthropod-borne zoonotic agents has been a growing public health concern. In particular, agents from the genus Alphavirus pose a significant risk to both animal and human health. Human alphaviral disease presents with either arthritogenic or encephalitic manifestations and is associated with significant morbidity and/or mortality. Unfortunately, there are presently no vaccines or antiviral measures approved for human use. The present review examines the ecology, epidemiology, disease, past outbreaks, and potential to cause contemporary outbreaks for several alphavirus pathogens.
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Affiliation(s)
- Sasha R. Azar
- Department of Pathology, The University of Texas Medical Branch, Galveston, TX 77555-0609, USA;
| | - Rafael K. Campos
- Department of Microbiology and Immunology, The University of Texas Medical Branch, Galveston, TX 77555-0609, USA;
| | | | - Vidyleison N. Camargos
- Host-Microorganism Interaction Lab, Department of Microbiology, Institute of Biological Sciences, Universidade Federal de Minas Gerais, Belo Horizonte 31270-901, Brazil;
| | - Shannan L. Rossi
- Department of Pathology, The University of Texas Medical Branch, Galveston, TX 77555-0609, USA;
- Institute for Human Infection and Immunity, University of Texas Medical Branch, Galveston, TX 77555-0610, USA
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Kading RC, Cohnstaedt LW, Fall K, Hamer GL. Emergence of Arboviruses in the United States: The Boom and Bust of Funding, Innovation, and Capacity. Trop Med Infect Dis 2020; 5:E96. [PMID: 32517268 PMCID: PMC7345222 DOI: 10.3390/tropicalmed5020096] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Revised: 06/01/2020] [Accepted: 06/04/2020] [Indexed: 11/16/2022] Open
Abstract
Mosquito-borne viruses will continue to emerge and generate a significant public health burden around the globe. Here, we provide a longitudinal perspective on how the emergence of mosquito-borne viruses in the Americas has triggered reactionary funding by sponsored agencies, stimulating a number of publications, innovative development of traps, and augmented capacity. We discuss the return on investment (ROI) from the oscillation in federal funding that influences demand for surveillance and control traps and leads to innovation and research productivity.
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Affiliation(s)
- Rebekah C. Kading
- Department of Microbiology, Colorado State University, Immunology and Pathology, Fort Collins, Colorado, CO 80523, USA
| | - Lee W. Cohnstaedt
- United States Department of Agriculture, Arthropod-borne Animal Diseases Research Unit, Agricultural Research Service, Manhattan, Kansas, KS 66502, USA;
| | - Ken Fall
- BioQuip Products, Rancho Dominguez, California, CA 90220, USA;
| | - Gabriel L. Hamer
- Department of Entomology, College of Agriculture and Life Sciences, Texas A&M University, College Station, Texas, TX 77843, USA;
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Bergren NA, Haller S, Rossi SL, Seymour RL, Huang J, Miller AL, Bowen RA, Hartman DA, Brault AC, Weaver SC. "Submergence" of Western equine encephalitis virus: Evidence of positive selection argues against genetic drift and fitness reductions. PLoS Pathog 2020; 16:e1008102. [PMID: 32027727 PMCID: PMC7029877 DOI: 10.1371/journal.ppat.1008102] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2019] [Revised: 02/19/2020] [Accepted: 09/22/2019] [Indexed: 11/18/2022] Open
Abstract
Understanding the circumstances under which arboviruses emerge is critical for the development of targeted control and prevention strategies. This is highlighted by the emergence of chikungunya and Zika viruses in the New World. However, to comprehensively understand the ways in which viruses emerge and persist, factors influencing reductions in virus activity must also be understood. Western equine encephalitis virus (WEEV), which declined during the late 20th century in apparent enzootic circulation as well as equine and human disease incidence, provides a unique case study on how reductions in virus activity can be understood by studying evolutionary trends and mechanisms. Previously, we showed using phylogenetics that during this period of decline, six amino acid residues appeared to be positively selected. To assess more directly the effect of these mutations, we utilized reverse genetics and competition fitness assays in the enzootic host and vector (house sparrows and Culex tarsalis mosquitoes). We observed that the mutations contemporary with reductions in WEEV circulation and disease that were non-conserved with respect to amino acid properties had a positive effect on enzootic fitness. We also assessed the effects of these mutations on virulence in the Syrian-Golden hamster model in relation to a general trend of increased virulence in older isolates. However, no change effect on virulence was observed based on these mutations. Thus, while WEEV apparently underwent positive selection for infection of enzootic hosts, residues associated with mammalian virulence were likely eliminated from the population by genetic drift or negative selection. These findings suggest that ecologic factors rather than fitness for natural transmission likely caused decreased levels of enzootic WEEV circulation during the late 20th century.
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Affiliation(s)
- Nicholas A. Bergren
- Institute for Human Infections and Immunity, University of Texas Medical Branch, Galveston, Texas, United States of America
- Department of Pathology, University of Texas Medical Branch, Galveston, Texas, United States of America
| | - Sherry Haller
- Institute for Human Infections and Immunity, University of Texas Medical Branch, Galveston, Texas, United States of America
- Department of Microbiology & Immunology, University of Texas Medical Branch, Galveston, Texas, United States of America
| | - Shannan L. Rossi
- Institute for Human Infections and Immunity, University of Texas Medical Branch, Galveston, Texas, United States of America
- Department of Microbiology & Immunology, University of Texas Medical Branch, Galveston, Texas, United States of America
| | - Robert L. Seymour
- Institute for Human Infections and Immunity, University of Texas Medical Branch, Galveston, Texas, United States of America
- Department of Pathology, University of Texas Medical Branch, Galveston, Texas, United States of America
| | - Jing Huang
- Institute for Human Infections and Immunity, University of Texas Medical Branch, Galveston, Texas, United States of America
| | - Aaron L. Miller
- Department of Pediatrics, University of Texas Medical Branch, Galveston, Texas, United States of America
| | - Richard A. Bowen
- Department of Microbiology, Immunology, and Pathology, Colorado State University, Fort Collins, Colorado, United States of America
- Department of Biomedical Sciences, Colorado State University, Fort Collins, Colorado, United States of America
| | - Daniel A. Hartman
- Department of Microbiology, Immunology, and Pathology, Colorado State University, Fort Collins, Colorado, United States of America
| | - Aaron C. Brault
- Division of Vector-Borne Diseases, Centers for Disease Control and Prevention, Fort Collins, Colorado, United States of America
| | - Scott C. Weaver
- Institute for Human Infections and Immunity, University of Texas Medical Branch, Galveston, Texas, United States of America
- Department of Pathology, University of Texas Medical Branch, Galveston, Texas, United States of America
- Department of Microbiology & Immunology, University of Texas Medical Branch, Galveston, Texas, United States of America
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Complete Coding Sequence of Western Equine Encephalitis Virus Strain Fleming, Isolated from a Human Case. Microbiol Resour Announc 2020; 9:9/1/e01223-19. [PMID: 31896634 PMCID: PMC6940286 DOI: 10.1128/mra.01223-19] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We sequenced the complete coding genome of the western equine encephalitis virus (WEEV) strain Fleming. This strain was originally isolated in 1938 from a human WEEV case.
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Hartman DA, Rice LM, DeMaria J, Borland EM, Bergren NA, Fagre AC, Robb LL, Webb CT, Kading RC. Entomological risk factors for potential transmission of Rift Valley fever virus around concentrations of livestock in Colorado. Transbound Emerg Dis 2019; 66:1709-1717. [PMID: 31002468 DOI: 10.1111/tbed.13206] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2019] [Revised: 04/11/2019] [Accepted: 04/12/2019] [Indexed: 01/07/2023]
Abstract
Rift Valley fever virus (RVFV) poses a major threat of introduction to several continents, including North America. Such an introduction could cause significant losses to the livestock industry, in addition to substantial human morbidity and mortality. Because of the opportunistic blood host selection of Culex tarsalis mosquitoes, we hypothesized that this species could be an important bridge vector of RVFV near feedlots in the event of an introduction. We investigated the mosquito community composition at livestock feedlots and surrounding natural and residential areas to determine differences in mosquito relative abundance and blood feeding patterns attributed to cattle feeding operations. DNA extracted from abdomens of blood-fed mosquitoes were sequenced to determine host identity. Multivariate regression analyses revealed differences between mosquito community assemblages at feedlots and non-feedlot sites (p < 0.05), with this effect driven largely by differential abundances of Aedes vexans (padj < 0.05). Mosquito diversity was lower on feedlots than surrounding areas for three out of four feedlots. Culex tarsalis was abundant at both feedlots and nearby sites. Diverse vertebrate blood meals were detected in Cx. tarsalis at non-feedlot sites, with a shift towards feeding on cattle at feedlots. These data support a potential for Cx. tarsalis to serve as a bridge vector of RVFV between livestock and humans in Colorado.
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Affiliation(s)
- Daniel A Hartman
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado
| | - Lauren M Rice
- Department of Biomedical Sciences, Colorado State University, Fort Collins, Colorado
| | - Justin DeMaria
- Department of Biomedical Sciences, Colorado State University, Fort Collins, Colorado
| | - Erin M Borland
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado
| | - Nicholas A Bergren
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado
| | - Anna C Fagre
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado
| | - Lucy L Robb
- Department of Biomedical Sciences, Colorado State University, Fort Collins, Colorado
| | - Colleen T Webb
- Department of Biology, Colorado State University, Fort Collins, Colorado
| | - Rebekah C Kading
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado
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