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Landers VD, Thomas M, Isom CM, Karki D, Sokoloski KJ. Capsid protein mediated evasion of IRAK1-dependent signalling is essential to Sindbis virus neuroinvasion and virulence in mice. Emerg Microbes Infect 2024; 13:2300452. [PMID: 38164715 PMCID: PMC10773654 DOI: 10.1080/22221751.2023.2300452] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2023] [Accepted: 12/22/2023] [Indexed: 01/03/2024]
Abstract
ABSTRACTAlphaviruses are arthropod-borne, single-stranded positive-sense RNA viruses that are recognized as rapidly emerging pathogens. Despite being exquisitely sensitive to the effects of the innate immune response alphaviruses can readily replicate, disseminate, and induce pathogenesis in immunologically competent hosts. Nonetheless, how alphaviruses evade the induction of an innate immune response prior to viral gene expression, or in non-permissive infections, is unknown. Previously we reported the identification of a novel host/pathogen interaction between the viral Capsid (CP) protein and the host IRAK1 protein. The CP/IRAK1 interaction was determined to negatively impact IRAK1-dependent PAMP detection in vitro, however, the precise importance of the CP/IRAK1 interaction to alphaviral infection remained unknown. Here we detail the identification of the CP/IRAK1 interaction determinants of the Sindbis virus (SINV) CP protein and examine the importance of the interaction to alphaviral infection and pathogenesis in vivo using an interaction deficient mutant of the model neurotropic strain of SINV. Importantly, these interaction determinants are highly conserved across multiple Old-World alphaviruses, including Ross River virus (RRV), Mayaro virus (MAYV), Chikungunya virus (CHIKV), and Semliki Forest virus (SFV). In the absence of a functional CP/IRAK1 interaction, SINV replication is significantly restricted and fails to disseminate from the primary site of inoculation due to the induction of a robust type-I Interferon response. Altogether these data indicate that the evasion of IRAK1-dependent signalling is critical to overcoming the host innate immune response and the in vivo data presented here demonstrate the importance of the CP/IRAK1 interaction to neurovirulence and pathogenesis.
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Affiliation(s)
- V Douglas Landers
- Department of Microbiology and Immunology, School of Medicine, University of Louisville, Louisville, KY, USA
| | - Milton Thomas
- Department of Microbiology and Immunology, School of Medicine, University of Louisville, Louisville, KY, USA
| | - Cierra M. Isom
- Department of Microbiology and Immunology, School of Medicine, University of Louisville, Louisville, KY, USA
| | - Deepa Karki
- Department of Microbiology and Immunology, School of Medicine, University of Louisville, Louisville, KY, USA
| | - Kevin J. Sokoloski
- Department of Microbiology and Immunology, School of Medicine, University of Louisville, Louisville, KY, USA
- Center for Predictive Medicine and Emerging Infectious Diseases, University of Louisville, Louisville, KY, USA
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Hickson SE, Hyde JL. RNA structures within Venezuelan equine encephalitis virus E1 alter macrophage replication fitness and contribute to viral emergence. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.04.09.588743. [PMID: 38645187 PMCID: PMC11030350 DOI: 10.1101/2024.04.09.588743] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/23/2024]
Abstract
Venezuelan equine encephalitis virus (VEEV) is a mosquito-borne +ssRNA virus belonging to the Togaviridae . VEEV is found throughout Central and South America and is responsible for periodic epidemic/epizootic outbreaks of febrile and encephalitic disease in equines and humans. Endemic/enzootic VEEV is transmitted between Culex mosquitoes and sylvatic rodents, whereas epidemic/epizootic VEEV is transmitted between mosquitoes and equids, which serve as amplification hosts during outbreaks. Epizootic VEEV emergence has been shown to arise from mutation of enzootic VEEV strains. Specifically, epizootic VEEV has been shown to acquire amino acid mutations in the E2 viral glycoprotein that facilitate viral entry and equine amplification. However, the abundance of synonymous mutations which accumulate across the epizootic VEEV genome suggests that other viral determinants such as RNA secondary structure may also play a role in VEEV emergence. In this study we identify novel RNA structures in the E1 gene which specifically alter replication fitness of epizootic VEEV in macrophages but not other cell types. We show that SNPs are conserved within epizootic lineages and that RNA structures are conserved across different lineages. We also identified several novel RNA-binding proteins that are necessary for altered macrophage replication. These results suggest that emergence of VEEV in nature requires multiple mutations across the viral genome, some of which alter cell-type specific replication fitness in an RNA structure-dependent manner. AUTHOR SUMMARY Understanding how viral pathogens emerge is critical for ongoing surveillance and outbreak preparedness. However, our understanding of the molecular mechanisms that drive viral emergence are still not completely understood. Emergence of the mosquito-borne virus Venezuelan equine encephalitis virus (VEEV) is known to require mutations in the viral attachment protein (E2), which drive viremia and transmission. We have observed that emergent strains (epizootic VEEV) also accumulate many silent mutations, suggesting that other determinants independent of protein sequence also contributes to emergence. In this study we identify novel RNA secondary structures associated with epizootic VEEV that alters viral replication in a cell-type dependent manner. We show that these RNA structures are conserved across epizootic viruses and identify host proteins that specifically bind these RNAs. These findings imply that viral emergence requires multiple mutations, a number of which likely alter viral structure in a manner that benefits viral replication and transmission.
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Burkett-Cadena ND, Fish D, Weaver S, Vittor AY. Everglades virus: an underrecognized disease-causing subtype of Venezuelan equine encephalitis virus endemic to Florida, USA. JOURNAL OF MEDICAL ENTOMOLOGY 2023; 60:1149-1164. [PMID: 37862065 PMCID: PMC10645373 DOI: 10.1093/jme/tjad070] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/03/2023] [Revised: 05/04/2023] [Accepted: 06/08/2023] [Indexed: 10/21/2023]
Abstract
Everglades virus (EVEV) is subtype II of the Venezuelan equine encephalitis virus (VEEV) complex (Togaviridae: Alphavirus), endemic to Florida, USA. EVEV belongs to a clade that includes both enzootic and epizootic/epidemic VEEV subtypes. Like other enzootic VEEV subtypes, muroid rodents are important vertebrate hosts for EVEV and certain mosquitoes are important vectors. The hispid cotton rat Sigmodon hispidus and cotton mouse Peromyscus gossypinus are important EVEV hosts, based on natural infection (virus isolation and high seropositivity), host competence (experimental infections), and frequency of contact with the vector. The mosquito Culex (Melanoconion) cecedei is the only confirmed vector of EVEV based upon high natural infection rates, efficient vector competence, and frequent feeding upon muroid rodents. Human disease attributed to EVEV is considered rare. However, cases of meningitis and encephalitis are recorded from multiple sites, separated by 250 km or more. Phylogenetic analyses indicate that EVEV is evolving, possibly due to changes in the mammal community. Mutations in the EVEV genome are of concern, given that epidemic strains of VEEV (subtypes IAB and IC) are derived from enzootic subtype ID, the closest genetic relative of EVEV. Should epizootic mutations arise in EVEV, the abundance of Aedes taeniorhynchus and other epizootic VEEV vectors in southern Florida provides a conducive environment for widespread transmission. Other factors that will likely influence the distribution and frequency of EVEV transmission include the establishment of Culex panocossa in Florida, Everglades restoration, mammal community decline due to the Burmese python, land use alteration by humans, and climate change.
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Affiliation(s)
- Nathan D Burkett-Cadena
- Florida Medical Entomology Laboratory, University of Florida Institute of Food and Agricultural Sciences, 200 9th St. SE, Vero Beach, FL 32962, USA
| | - Durland Fish
- Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, CT, USA
| | - Scott Weaver
- Department of Pathology, Center for Biodefense and Emerging Infectious Disease, University of Texas Medical Branch, Galveston, TX 77555-0609, USA
| | - Amy Y Vittor
- Department of Medicine & Emerging Pathogens Institute, University of Florida, Gainesville, FL 32611, USA
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León B, González G, Nicoli A, Rojas A, Pizio AD, Ramirez-Carvajal L, Jimenez C. Phylogenetic and Mutation Analysis of the Venezuelan Equine Encephalitis Virus Sequence Isolated in Costa Rica from a Mare with Encephalitis. Vet Sci 2022; 9:258. [PMID: 35737310 PMCID: PMC9229380 DOI: 10.3390/vetsci9060258] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2022] [Revised: 05/19/2022] [Accepted: 05/25/2022] [Indexed: 12/10/2022] Open
Abstract
Venezuelan Equine Encephalitis virus (VEEV) is an arboviral pathogen in tropical America that causes lethal encephalitis in horses and humans. VEEV is classified into six subtypes (I to VI). Subtype I viruses are divided into epizootic (IAB and IC) and endemic strains (ID and IE) that can produce outbreaks or sporadic diseases, respectively. The objective of this study was to reconstruct the phylogeny and the molecular clock of sequences of VEEV subtype I complex and identify mutations within sequences belonging to epizootic or enzootic subtypes focusing on a sequence isolated from a mare in Costa Rica. Bayesian phylogeny of the VEEV subtype I complex tree with 110 VEEV complete genomes was analyzed. Evidence of positive selection was evaluated with Datamonkey server algorithms. The putative effects of mutations on the 3D protein structure in the Costa Rica sequence were evaluated. The phylogenetic analysis showed that Subtype IE-VEEV diverged earlier than other subtypes, Costa Rican VEEV-IE ancestors came from Nicaragua in 1963 and Guatemala in 1907. Among the observed non-synonymous mutations, only 17 amino acids changed lateral chain groups. Fourteen mutations located in the NSP3, E1, and E2 genes are unique in this sequence, highlighting the importance of E1-E2 genes in VEEV evolution.
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Affiliation(s)
- Bernal León
- LSE Laboratory, Veterinary Service National Laboratory, Animal Health National Service, Ministry of Agriculture and Cattle, Heredia 40104, Costa Rica
- Virology, Universidad Técnica Nacional (UTN), Atenas 20505, Costa Rica
| | - Gabriel González
- National Virus Reference Laboratory, College Dublin, D04 V1W8 Belfield, Ireland;
| | - Alessandro Nicoli
- Leibniz Institute for Food Systems Biology at the Technical University of Munich, 85354 Freising, Germany; (A.N.); (A.D.P.)
| | - Alicia Rojas
- Laboratory of Helminthology, Centro de Investigación en Enfermedades Tropicales, University of Costa Rica, San José 11501, Costa Rica;
| | - Antonella Di Pizio
- Leibniz Institute for Food Systems Biology at the Technical University of Munich, 85354 Freising, Germany; (A.N.); (A.D.P.)
| | - Lisbeth Ramirez-Carvajal
- Veterinary Medicine Infection and Immunity, Virology, University of Utrecht, 3584 CS Utrecht, The Netherlands;
| | - Carlos Jimenez
- Laboratory of Virology, Tropical Diseases Research Program (PIET), School of Veterinary Medicine, Universidad Nacional, Heredia 40101, Costa Rica;
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Evaluating sampling strategies for enzootic Venezuelan equine encephalitis virus vectors in Florida and Panama. PLoS Negl Trop Dis 2022; 16:e0010329. [PMID: 35417476 PMCID: PMC9007344 DOI: 10.1371/journal.pntd.0010329] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2021] [Accepted: 03/14/2022] [Indexed: 11/19/2022] Open
Abstract
Determining effective sampling methods for mosquitoes are among the first objectives in elucidating transmission cycles of vector-borne zoonotic disease, as the effectiveness of sampling methods can differ based on species, location, and physiological state. The Spissipes section of the subgenus Melanoconion of Culex represents an understudied group of mosquitoes which transmit Venezuelan equine encephalitis viruses (VEEV) in the Western Hemisphere. The objective of this study was to determine effective collection methods that target both blood-engorged and non-engorged females of the Spissipes section of Culex subgenus Melanoconion to test the hypothesis that favorable trapping methods differ between species and by physiological status within a species. Mosquitoes were collected using two commercially available traps, (CDC-light trap and BG-Sentinel trap), two novel passive traps (a novel mosquito drift fence and pop-up resting shelters), and two novel aspirators, (a small-diameter aspirator and a large-diameter aspirator) in Darién, Panama, and Florida, USA. The total number of female mosquitoes collected for each species was compared using rarefaction curves and diversity metrics. We also compared the utility of each trap for collecting total females and blood-engorged females of four Spissipes section mosquito species in Florida and Darién. In Darién, it was found that both blood-engorged and unfed females of Cx. pedroi were most effectively collected using the mosquito drift fence at 57.6% and 61.7% respectively. In contrast, the most unfed Cx. spissipes were collected using the mosquito drift fence (40.7%) while blood-engorged females were collected effectively by pop-up resting shelters (42.3%). In Florida, the best sampling technique for the collection of blood-engorged Cx. panocossa was the large diameter aspirator at 41.9%, while the best trap for collecting Cx. cedecei was the pop-up resting shelter at 45.9%. For unfed female Spissipes section mosquitoes in Florida, the CDC light trap with CO2 collected 84.5% and 98.3% of Cx. cedecei and Cx. panocossa respectively in Florida. Rarefaction analysis, and both the Shannon and Simpsons diversity indices all demonstrated that the mosquito drift fence was capable of collecting the greatest diversity of mosquito species regardless of location. The finding that the proportions of unfed and blood-engorged mosquitoes collected by traps differed both among and between species has implications for how studies of VEEV vectors will be carried out in future investigations. In Florida a combination of pop-up resting shelters and use of a large-diameter aspirator would be optimal for the collection of both VEEV vectors for host-use studies. Results demonstrate that traps can be constructed from common materials to collect mosquitoes for VEEV vector studies and could be assessed for their utilization in vectors of other systems as well. Unfortunately, no single method was effective for capturing all species and physiological states, highlighting a particular need for assessing trap utility for target species of a study. Venezuelan equine encephalitis virus is a potentially deadly human pathogen that is transmitted by an understudied group of tropical mosquitoes (Spissipes section of the Culex subgenus Melanoconion). These mosquitoes reside in swamps and jungles, and are challenging to identify, so studying their biology and importance in transmitting VEEV has been neglected. To further our understanding of VEEV, we compared six novel and commercially available traps to determine which traps are best for capturing these species in Panama and Florida. We found that several different types of traps are effective for collecting blood-engorged females of different species of VEEV vectors, and that traps utilized for collecting unfed specimens are not necessarily the same traps one should use for collecting blood-engorged females of the same species. Results of this study will enable researchers to better capture these important disease vectors, particularly those that are blood-engorged, which will allow researchers to determine host associations necessary for understanding VEEV transmission. This information can be used to make decisions on controlling vector species.
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The Alphaviral Capsid Protein Inhibits IRAK1-Dependent TLR Signaling. Viruses 2021; 13:v13030377. [PMID: 33673546 PMCID: PMC7997285 DOI: 10.3390/v13030377] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2021] [Revised: 02/24/2021] [Accepted: 02/26/2021] [Indexed: 12/20/2022] Open
Abstract
Alphaviruses are arthropod-borne RNA viruses which can cause either mild to severe febrile arthritis which may persist for months, or encephalitis which can lead to death or lifelong cognitive impairments. The non-assembly molecular role(s), functions, and protein–protein interactions of the alphavirus capsid proteins have been largely overlooked. Here we detail the use of a BioID2 biotin ligase system to identify the protein–protein interactions of the Sindbis virus capsid protein. These efforts led to the discovery of a series of novel host–pathogen interactions, including the identification of an interaction between the alphaviral capsid protein and the host IRAK1 protein. Importantly, this capsid–IRAK1 interaction is conserved across multiple alphavirus species, including arthritogenic alphaviruses SINV, Ross River virus, and Chikungunya virus; and encephalitic alphaviruses Eastern Equine Encephalitis virus, and Venezuelan Equine Encephalitis virus. The impact of the capsid–IRAK1 interaction was evaluated using a robust set of cellular model systems, leading to the realization that the alphaviral capsid protein specifically inhibits IRAK1-dependent signaling. This inhibition represents a means by which alphaviruses may evade innate immune detection and activation prior to viral gene expression. Altogether, these data identify novel capsid protein–protein interactions, establish the capsid–IRAK1 interaction as a common alphavirus host–pathogen interface, and delineate the molecular consequences of the capsid–IRAK1 interaction on IRAK1-dependent signaling.
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Rossi SL, Russell-Lodrigue KE, Plante KS, Bergren NA, Gorchakov R, Roy CJ, Weaver SC. Rationally Attenuated Vaccines for Venezuelan Equine Encephalitis Protect Against Epidemic Strains with a Single Dose. Vaccines (Basel) 2020; 8:E497. [PMID: 32887313 PMCID: PMC7563393 DOI: 10.3390/vaccines8030497] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2020] [Revised: 08/31/2020] [Accepted: 08/31/2020] [Indexed: 12/24/2022] Open
Abstract
Venezuelan equine encephalitis virus (VEEV) is a re-emerging virus of human, agriculture, and bioweapon threat importance. No FDA-approved treatment is available to combat Venezuelan equine encephalitis in humans, prompting the need to create a vaccine that is safe, efficacious, and cannot be replicated in the mosquito vector. Here we describe the use of a serotype ID VEEV (ZPC-738) vaccine with an internal ribosome entry site (IRES) to alter gene expression patterns. This ZPC/IRES vaccine was genetically engineered in two ways based on the position of the IRES insertion to create a vaccine that is safe and efficacious. After a single dose, both versions of the ZPC/IRES vaccine elicited neutralizing antibody responses in mice and non-human primates after a single dose, with more robust responses produced by version 2. Further, all mice and primates were protected from viremia following VEEV challenge. These vaccines were also safer in neonatal mice than the current investigational new drug vaccine, TC-83. These results show that IRES-based attenuation of alphavirus genomes consistently produce promising vaccine candidates, with VEEV/IRES version 2 showing promise for further development.
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Affiliation(s)
- Shannan L. Rossi
- Department of Pathology and Microbiology and Immunology, Institute for Human Infection and Immunity, University of Texas Medical Branch, Galveston, TX 77555, USA
| | | | - Kenneth S. Plante
- Department of Microbiology and Immunology and World Reference Center for Emerging Viruses and Arboviruses, University of Texas Medical Branch, Galveston, TX 77555, USA;
| | - Nicholas A. Bergren
- Department of Pathology, University of Texas Medical Branch, Galveston, TX 77555, USA;
| | - Rodion Gorchakov
- Department of Health, Safety and Environment, King Abdullah University of Science and Technology, Thuwal 23955, Saudi Arabia;
| | - Chad J. Roy
- Tulane National Primate Research Center, Covington, LA 70433, USA; (K.E.R.-L.); (C.J.R.)
- Department of Microbiology and Immunology, Tulane School of Medicine, New Orleans, LA 70112, USA
| | - Scott C. Weaver
- World Reference Center for Emerging Viruses and Arboviruses, University of Texas Medical Branch, Galveston, TX 77555, USA
- Institute for Human Infection and Immunity, University of Texas Medical Branch, Galveston, TX 77555, USA
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, TX 77555, USA
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Carrera JP, Pittí Y, Molares-Martínez JC, Casal E, Pereyra-Elias R, Saenz L, Guerrero I, Galué J, Rodriguez-Alvarez F, Jackman C, Pascale JM, Armien B, Weaver SC, Donnelly CA, Vittor AY. Clinical and Serological Findings of Madariaga and Venezuelan Equine Encephalitis Viral Infections: A Follow-up Study 5 Years After an Outbreak in Panama. Open Forum Infect Dis 2020; 7:ofaa359. [PMID: 33005697 PMCID: PMC7518370 DOI: 10.1093/ofid/ofaa359] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2020] [Accepted: 08/13/2020] [Indexed: 11/15/2022] Open
Abstract
BACKGROUND Human cases of Madariaga virus (MADV) infection were first detected during an outbreak in 2010 in eastern Panama, where Venezuelan equine encephalitis virus (VEEV) also circulates. Little is known about the long-term consequences of either alphavirus infection. METHODS A follow-up study of the 2010 outbreak was undertaken in 2015. An additional survey was carried out 2 weeks after a separate 2017 alphavirus outbreak in a neighboring population in eastern Panama. Serological studies and statistical analyses were undertaken in both populations. RESULTS Among the originally alphavirus-seronegative participants (n = 35 of 65), seroconversion was observed at a rate of 14.3% (95% CI, 4.8%-30.3%) for MADV and 8.6% (95% CI, 1.8%-23.1%) for VEEV over 5 years. Among the originally MADV-seropositive participants (n = 14 of 65), VEEV seroconversion occurred in 35.7% (95% CI, 12.8%-64.9%). In the VEEV-seropositive participants (n = 16 of 65), MADV seroconversion occurred in 6.3% (95% CI, 0.2%-30.2%). MADV seroreversion was observed in 14.3% (95% CI, 1.8%-42.8%) of those who were originally seropositive in 2010. VEEV seroconversion in the baseline MADV-seropositive participants was significantly higher than in alphavirus-negative participants. In the population sampled in 2017, MADV and VEEV seroprevalence was 13.2% and 16.8%, respectively. Memory loss, insomnia, irritability, and seizures were reported significantly more frequently in alphavirus-seropositive participants than in seronegative participants. CONCLUSIONS High rates of seroconversion to MADV and VEEV over 5 years suggest frequent circulation of both viruses in Panama. Enhanced susceptibility to VEEV infection may be conferred by MADV infection. We provide evidence of persistent neurologic symptoms up to 5 years following MADV and VEEV exposure.
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Affiliation(s)
- Jean-Paul Carrera
- Department of Zoology, University of Oxford, Oxford, UK
- Department of Research in Virology and Biotechnology, Gorgas Memorial Institute of Health Studies, Panama City, Panama
| | - Yaneth Pittí
- Department of Research in Virology and Biotechnology, Gorgas Memorial Institute of Health Studies, Panama City, Panama
| | - Juan C Molares-Martínez
- Department of Research in Virology and Biotechnology, Gorgas Memorial Institute of Health Studies, Panama City, Panama
| | - Eric Casal
- Department of Research in Virology and Biotechnology, Gorgas Memorial Institute of Health Studies, Panama City, Panama
| | - Reneé Pereyra-Elias
- National Perinatal Epidemiology Unit, Nuffield Department of Population Health, University of Oxford, Oxford, United Kingdom
| | - Lisseth Saenz
- Department of Research in Virology and Biotechnology, Gorgas Memorial Institute of Health Studies, Panama City, Panama
| | - Isela Guerrero
- Department of Research in Virology and Biotechnology, Gorgas Memorial Institute of Health Studies, Panama City, Panama
| | - Josefrancisco Galué
- Department of Research in Virology and Biotechnology, Gorgas Memorial Institute of Health Studies, Panama City, Panama
| | - Fatima Rodriguez-Alvarez
- Department of Research in Virology and Biotechnology, Gorgas Memorial Institute of Health Studies, Panama City, Panama
| | - Carmela Jackman
- Department of Epidemiology, Ministry of Health, Panama, Panama
| | - Juan Miguel Pascale
- Clinical Research Unit, Gorgas Memorial Institute of Health Studies, Panama City, Panama
| | - Blas Armien
- Department of Research in Emerging and Zoonotic Diseases, Gorgas Memorial Institute of Health Studies, Panama City, Panama
| | - Scott C Weaver
- Institute for Human Infection and Immunity, Department of Microbiology and Immunology, Department of Pathology, and World Reference Center for Emerging Viruses and Arboviruses, University of Texas Medical Branch, Galveston, Texas, USA
| | - Christl A Donnelly
- MRC Centre for Global Infectious Disease Analysis, Department of Infectious Disease Epidemiology, Imperial College London, London, UK
- Department of Statistics, University of Oxford, Oxford, UK
| | - Amy Y Vittor
- Division of Infectious Disease and Global Medicine, Department of Medicine, University of Florida, Gainesville, Florida, USA
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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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Rusnak JM, Glass PJ, Weaver SC, Sabourin CL, Glenn AM, Klimstra W, Badorrek CS, Nasar F, Ward LA. Approach to Strain Selection and the Propagation of Viral Stocks for Venezuelan Equine Encephalitis Virus Vaccine Efficacy Testing under the Animal Rule. Viruses 2019; 11:v11090807. [PMID: 31480472 PMCID: PMC6784384 DOI: 10.3390/v11090807] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2019] [Revised: 08/23/2019] [Accepted: 08/30/2019] [Indexed: 12/21/2022] Open
Abstract
Licensure of a vaccine to protect against aerosolized Venezuelan equine encephalitis virus (VEEV) requires use of the U.S. Food and Drug Administration (FDA) Animal Rule to assess vaccine efficacy as human studies are not feasible or ethical. An approach to selecting VEEV challenge strains for use under the Animal Rule was developed, taking into account Department of Defense (DOD) vaccine requirements, FDA Animal Rule guidelines, strain availability, and lessons learned from the generation of filovirus challenge agents within the Filovirus Animal Nonclinical Group (FANG). Initial down-selection to VEEV IAB and IC epizootic varieties was based on the DOD objective for vaccine protection in a bioterrorism event. The subsequent down-selection of VEEV IAB and IC isolates was based on isolate availability, origin, virulence, culture and animal passage history, known disease progression in animal models, relevancy to human disease, and ability to generate sufficient challenge material. Methods for the propagation of viral stocks (use of uncloned (wild-type), plaque-cloned, versus cDNA-cloned virus) to minimize variability in the potency of the resulting challenge materials were also reviewed. The presented processes for VEEV strain selection and the propagation of viral stocks may serve as a template for animal model development product testing under the Animal Rule to other viral vaccine programs. This manuscript is based on the culmination of work presented at the “Alphavirus Workshop” organized and hosted by the Joint Vaccine Acquisition Program (JVAP) on 15 December 2014 at Fort Detrick, Maryland, USA.
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Affiliation(s)
- Janice M Rusnak
- Joint Program Executive Office for Chemical, Biological, Radiological and Nuclear Defense (JPEO-CBRND), Joint Project Manager-Medical Countermeasure Systems (JMP-MCS), Joint Vaccine Acquisition Program (JVAP), 1564 Freedman Drive, Fort Detrick, MD 21702, USA.
| | - Pamela J Glass
- Department of Virology, United States Army Medical Research Institute of Infectious Diseases (USAMRIID), 1425 Porter Street, Fort Detrick, MD 21702, USA
| | - Scott C Weaver
- Institute for Human Infections and Immunity, World Reference Center for Emerging Viruses and Arboviruses and Department of Microbiology and Immunology, University of Texas Medical Branch, 301 University Boulevard, Galveston, TX 77555, USA
| | - Carol L Sabourin
- Battelle Biomedical Research Center, 1425 Plain City-Georgesville Road, West Jefferson, OH 43162, USA
| | - Andrew M Glenn
- Joint Program Executive Office for Chemical, Biological, Radiological and Nuclear Defense (JPEO-CBRND), Joint Project Manager-Medical Countermeasure Systems (JMP-MCS), Joint Vaccine Acquisition Program (JVAP), 1564 Freedman Drive, Fort Detrick, MD 21702, USA
| | - William Klimstra
- Center for Vaccine Research, University of Pittsburgh, 3501 Fifth Avenue, Pittsburgh, PA 15261, USA
| | - Christopher S Badorrek
- Joint Program Executive Office for Chemical, Biological, Radiological and Nuclear Defense (JPEO-CBRND), Joint Project Manager-Medical Countermeasure Systems (JMP-MCS), Joint Vaccine Acquisition Program (JVAP), 1564 Freedman Drive, Fort Detrick, MD 21702, USA
| | - Farooq Nasar
- Department of Virology, United States Army Medical Research Institute of Infectious Diseases (USAMRIID), 1425 Porter Street, Fort Detrick, MD 21702, USA
| | - Lucy A Ward
- Joint Program Executive Office for Chemical, Biological, Radiological and Nuclear Defense (JPEO-CBRND), Joint Project Manager-Medical Countermeasure Systems (JMP-MCS), Joint Vaccine Acquisition Program (JVAP), 1564 Freedman Drive, Fort Detrick, MD 21702, USA
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Cardozo F, Konigheim B, Albrieu-Llinás G, Rivarola ME, Aguilar J, Rojas A, Quaglia AI, Paez M, Guillén Y, Diaz A, Vallejos MA, Herebia L, Recalde ML, Contigiani MS, Mendoza L. Alphaviruses: Serological Evidence of Human Infection in Paraguay (2012-2013). Vector Borne Zoonotic Dis 2018; 18:266-272. [PMID: 29652644 DOI: 10.1089/vbz.2017.2178] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
INTRODUCTION Alphaviruses can produce febrile illness and encephalitis in dead-end hosts such as horses and humans. Within this genus, the Venezuelan Equine Encephalitis virus (VEEV) complex includes pathogenic epizootic subtypes and enzootic subtypes that are not pathogenic in horses (except subtype IE, Mexican strains), although they can cause febrile symptoms in humans. The Rio Negro virus (RNV-VEEV subtype VI) circulates in Argentina, where it was associated with undifferentiated febrile illness. Mayaro (MAYV) and Una (UNAV) viruses belong to a different group, the Semliki Forest virus complex, with confirmed circulation. OBJECTIVE The present study aimed to determine RNV, MAYV, and UNAV seroprevalences by plaque reduction neutralization test in 652 samples of Paraguayan individuals mainly from the Central Department, between years 2012 and 2013. METHODS Samples with antibodies titer >1:20 against RNV were also tested for Mosso das Pedras-subtype IF, subtype IAB, and Pixuna (PIXV)-subtype IV viruses that belongs to VEEV antigenic complex. RESULTS The overall seroprevalence of RNV was 3.83%, and for UNAV it was 0.46%, and no neutralizing antibodies were detected against MAYV in the studied population. Two of the twenty-seven heterotypic samples were positive for PIXV. The 50.1% of neutralizing antibody titers against RNV were high (equal to or greater than 1/640), suggesting recent infections. The effect of age on the prevalence of RNV was negligible. CONCLUSIONS These results bring new information about neglected alphaviruses in South America, and these data will serve as the basis for future studies of seroprevalence of other VEEV, and studies to search potential hosts and vectors of these viruses in the region.
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Affiliation(s)
- Fátima Cardozo
- 1 Research Institute in Health Sciences, National University of Asunción , San Lorenzo, Paraguay
| | - Brenda Konigheim
- 2 Facultad de Ciencias Médicas, "Dr. J.M. Vanella", Instituto de Virología, CONICET, Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Guillermo Albrieu-Llinás
- 2 Facultad de Ciencias Médicas, "Dr. J.M. Vanella", Instituto de Virología, CONICET, Universidad Nacional de Córdoba, Córdoba, Argentina
| | - María Elisa Rivarola
- 2 Facultad de Ciencias Médicas, "Dr. J.M. Vanella", Instituto de Virología, CONICET, Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Javier Aguilar
- 2 Facultad de Ciencias Médicas, "Dr. J.M. Vanella", Instituto de Virología, CONICET, Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Alejandra Rojas
- 1 Research Institute in Health Sciences, National University of Asunción , San Lorenzo, Paraguay
| | - Agustín Ignacio Quaglia
- 2 Facultad de Ciencias Médicas, "Dr. J.M. Vanella", Instituto de Virología, CONICET, Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Malvina Paez
- 1 Research Institute in Health Sciences, National University of Asunción , San Lorenzo, Paraguay
| | - Yvalena Guillén
- 1 Research Institute in Health Sciences, National University of Asunción , San Lorenzo, Paraguay
| | - Adrian Diaz
- 2 Facultad de Ciencias Médicas, "Dr. J.M. Vanella", Instituto de Virología, CONICET, Universidad Nacional de Córdoba, Córdoba, Argentina
| | | | | | | | - Marta Silvia Contigiani
- 2 Facultad de Ciencias Médicas, "Dr. J.M. Vanella", Instituto de Virología, CONICET, Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Laura Mendoza
- 1 Research Institute in Health Sciences, National University of Asunción , San Lorenzo, Paraguay
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12
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Vignuzzi M, Higgs S. The Bridges and Blockades to Evolutionary Convergence on the Road to Predicting Chikungunya Virus Evolution. Annu Rev Virol 2017; 4:181-200. [PMID: 28961411 DOI: 10.1146/annurev-virology-101416-041757] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Chikungunya virus, first isolated in the 1950s, has since reemerged to cause several epidemics and millions of infections throughout the world. What was once blurred and confused with dengue virus in both diagnosis and name has since become one of the best-characterized arboviral diseases. In this review, we cover the history of this virus, its evolution into distinct genotypes and lineages, and, most notably, the convergent evolution observed in recent years. We highlight research that reveals to what extent convergent evolution, and its inherent predictability, may occur and what genetic or environmental factors may hinder it.
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Affiliation(s)
- Marco Vignuzzi
- Institut Pasteur, Viral Populations and Pathogenesis Unit, CNRS UMR 3569, 75724 Paris Cedex 15, France;
| | - Stephen Higgs
- Biosecurity Research Institute and Department of Diagnostic Medicine and Pathobiology, Kansas State University, Manhattan, Kansas 66506;
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13
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Torres R, Samudio R, Carrera JP, Young J, Márquez R, Hurtado L, Weaver S, Chaves LF, Tesh R, Cáceres L. Enzootic mosquito vector species at equine encephalitis transmission foci in the República de Panamá. PLoS One 2017; 12:e0185491. [PMID: 28937995 PMCID: PMC5609755 DOI: 10.1371/journal.pone.0185491] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2017] [Accepted: 09/13/2017] [Indexed: 11/18/2022] Open
Abstract
The identification of mosquito vector species present at arboviral enzootic transmission foci is important to understand transmission eco-epidemiology and to propose and implement prevention and control strategies that reduce vector-borne equine encephalitis transmission. The goal of this study was to identify mosquito species potentially involved in the transmission of enzootic equine encephalitis, in relation to their abundance and diversity at three endemic regions in the República de Panamá. We sampled adult mosquitoes during the dry and rainy season of Panamá. We employed CDC light traps with octanol, EV traps with CO2 and Trinidad 17 traps baited with live hamsters. Traps were deployed in the peridomicile and extradomicile of houses from 18:00 to 6:00 h. We estimated the abundance and diversity of sampled species. We collected a total of 4868 mosquitoes, belonging to 45 species and 11 genera, over 216 sampling nights. Culex (Melanoconion) pedroi, a major Venezuelan equine encephalitis vector was relatively rare (< 2.0% of all sampled mosquitoes). We also found Cx. (Mel) adamesi, Cx. (Mel) crybda, Cx. (Mel) ocossa, Cx. (Mel) spissipes, Cx. (Mel) taeniopus, Cx. (Mel) vomerifer, Aedes scapularis, Ae. angustivittatus, Coquillettidia venezuelensis, Cx. nigripalpus, Cx. declarator, Mansonia titillans, M. pseudotitillans and Psorophora ferox all species known to be vectorially competent for the transmission of arboviruses. Abundance and diversity of mosquitoes in the sampled locations was high, when compared with similar surveys in temperate areas. Information from previous reports about vectorial competence / capacity of the sampled mosquito species suggest that sampled locations have all the elements to support enzootic outbreaks of Venezuelan and Eastern equine encephalitides.
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Affiliation(s)
- Rolando Torres
- Instituto Commemorativo Gorgas de Estudios de la Salud, Ciudad de Panamá, República de Panamá, Departmento de Entomología Medica
| | - Rafael Samudio
- Mastozoological Society of Panamá, Ciudad de Panamá, República de Panamá
| | - Jean-Paul Carrera
- Instituto Commemorativo Gorgas de Estudios de la Salud, Ciudad de Panamá República de Panamá, Departmento de Genomica y Proteomica
| | - Josue Young
- Instituto Commemorativo Gorgas de Estudios de la Salud, Ciudad de Panamá, República de Panamá, Departmento de Entomología Medica
| | - Ricardo Márquez
- Instituto Commemorativo Gorgas de Estudios de la Salud, Ciudad de Panamá, República de Panamá, Departmento de Entomología Medica
| | - Lisbeth Hurtado
- Instituto Commemorativo Gorgas de Estudios de la Salud, Ciudad de Panamá, República de Panamá, Departmento de Análisis Epidemiológico y Bioestadísticas
| | - Scott Weaver
- Institute for Human Infections and Immunity and Department of Pathology, University of Texas Medical Branch, Galveston, TX, United States of America
| | - Luis Fernando Chaves
- Programa de Investigación en Enfermedades Tropicales (PIET), Escuela de Medicina Veterinaria, Universidad Nacional, Heredia, Costa Rica
- Centro de Investigación en Enfermedades Tropicales (CIET), Universidad de Costa Rica, San Pedro de Montes de Oca, Costa Rica
| | - Robert Tesh
- Institute for Human Infections and Immunity and Department of Pathology, University of Texas Medical Branch, Galveston, TX, United States of America
| | - Lorenzo Cáceres
- Instituto Commemorativo Gorgas de Estudios de la Salud, Ciudad de Panamá, República de Panamá, Departmento de Entomología Medica
- * E-mail:
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14
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Torres-Gutierrez C, Bergo ES, Emerson KJ, de Oliveira TM, Greni S, Sallum MAM. Mitochondrial COI gene as a tool in the taxonomy of mosquitoes Culex subgenus Melanoconion. Acta Trop 2016; 164:137-149. [PMID: 27609637 DOI: 10.1016/j.actatropica.2016.09.007] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2016] [Revised: 09/01/2016] [Accepted: 09/05/2016] [Indexed: 01/03/2023]
Abstract
The subgenus Melanoconion is the second largest subgenus within the genus Culex, with 160 described species. Several of the species are proven vectors of arboviruses, including West Nile virus, Venezuelan equine encephalitis virus complex and Eastern equine encephalomyelitis virus. Species of Melanoconion are well distributed from southern North America to most countries of South America and display the highest species diversity in tropical regions. Taxonomical identification within this group has been primarily based on morphological characters, with the male genitalia as the source of the most solid diagnostic features. The difficulty in reaching accurate species determinations when studying specimens of Culex (Melanoconion) has been extensively documented as a real limitation to expand knowledge of these insects. We tested the utility of the mitochondrial gene COI as a complementary tool in the taxonomy of Melanoconion. Using a data set of 120 COI sequences from Culex specimen captured in several localities in Brazil, the utility of COI barcodes for species delimitation is discussed through the evaluation of genetic divergences among specimens and the clustering patterns of species in three topologies obtained with Neighbor Joining, Maximum Likelihood and Bayesian phylogenetic inference. For all specimens included in this study a previous morphological examination was performed, and most of the taxonomical determinations were corroborated using the COI barcode. We generated COI sequences that belong to 48 species of Melanoconion, with a mean intraspecific K2P genetic divergence of 3%; and all interspecific divergence values higher than the intraspecific divergence values. This is the first comprehensive study of subgenus Melanoconion, with evidence of COI as a useful and accessible DNA barcode.
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Neurotropic virus infections as the cause of immediate and delayed neuropathology. Acta Neuropathol 2016; 131:159-184. [PMID: 26659576 PMCID: PMC4713712 DOI: 10.1007/s00401-015-1511-3] [Citation(s) in RCA: 199] [Impact Index Per Article: 24.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2015] [Revised: 10/24/2015] [Accepted: 11/17/2015] [Indexed: 12/30/2022]
Abstract
A wide range of viruses from different virus families in different geographical areas, may cause immediate or delayed neuropathological changes and neurological manifestations in humans and animals. Infection by neurotropic viruses as well as the resulting immune response can irreversibly disrupt the complex structural and functional architecture of the central nervous system, frequently leaving the patient or affected animal with a poor or fatal prognosis. Mechanisms that govern neuropathogenesis and immunopathogenesis of viral infections are highlighted, using examples of well-studied virus infections that are associated with these alterations in different populations throughout the world. A better understanding of the molecular, epidemiological and biological characteristics of these infections and in particular of mechanisms that underlie their clinical manifestations may be expected to provide tools for the development of more effective intervention strategies and treatment regimens.
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16
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Affiliation(s)
- John E Greenlee
- Department of Neurology, George E. Wahlen Veterans Affairs Medical Center, University of Utah Health Sciences, Salt Lake City, UT, USA.
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17
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Small molecule inhibitors of Ago2 decrease Venezuelan equine encephalitis virus replication. Antiviral Res 2014; 112:26-37. [PMID: 25448087 DOI: 10.1016/j.antiviral.2014.10.002] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2014] [Revised: 10/01/2014] [Accepted: 10/07/2014] [Indexed: 12/24/2022]
Abstract
Venezuelan equine encephalitis virus (VEEV) is classified as a Category B Select Agent and potential bioterror weapon for its severe disease course in humans and equines and its potential for aerosol transmission. There are no current FDA licensed vaccines or specific therapies against VEEV, making identification of potential therapeutic targets a priority. With this aim, our research focuses on the interactions of VEEV with host microRNA (miRNA) machinery. miRNAs are small non-coding RNAs that act as master regulators of gene expression by downregulating or degrading messenger RNA, thus suppressing production of the resultant proteins. Recent publications implicate miRNA interactions in the pathogenesis of various viral diseases. To test the importance of miRNA processing for VEEV replication, cells deficient in Ago2, an important component of the RNA-induced silencing complex (RISC), and cells treated with known Ago2 inhibitors, notably acriflavine (ACF), were utilized. Both conditions caused decreased viral replication and capsid expression. ACF treatment promoted increased survival of neuronal cells over a non-treated, infected control and reduced viral titers of fully virulent VEEV as well as Eastern and Western Equine Encephalitis Viruses and West Nile Virus, but not Vesicular Stomatitis Virus. ACF treatment of VEEV TC-83 infected mice resulted in increased in vivo survival, but did not affect survival or viral loads when mice were challenged with fully virulent VEEV TrD. These results suggest that inhibition of Ago2 results in decreased replication of encephalitic alphaviruses in vitro and this pathway may be an avenue to explore for future therapeutic development.
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18
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Pisano MB, Torres C, Ré VE, Farías AA, Sánchez Seco MP, Tenorio A, Campos R, Contigiani MS. Genetic and evolutionary characterization of Venezuelan equine encephalitis virus isolates from Argentina. INFECTION GENETICS AND EVOLUTION 2014; 26:72-9. [PMID: 24833218 DOI: 10.1016/j.meegid.2014.05.011] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/07/2014] [Revised: 04/29/2014] [Accepted: 05/06/2014] [Indexed: 11/27/2022]
Abstract
Venezuelan equine encephalitis viruses (VEEV) are emerging pathogens of medical and veterinary importance circulating in America. Argentina is a country free from epizootic VEEV activity, with circulation of enzootic strains belonging to Rio Negro virus (RNV; VEEV subtype VI) and Pixuna virus (PIXV, VEEV subtype IV). In this work, we aim to report the sequencing and phylogenetic analyses of all Argentinean VEE viruses, including 7 strains previously isolated from mosquitoes in 1980, 5 sequences obtained from rodents in 1991 and 11 sequences amplified from mosquitoes between 2003 and 2005. Two genomic regions, corresponding to the non-structural protein 4 (nsP4) and the protein E3/E2 (PE2) genes were analyzed, but only 8 samples could be amplified in the last one (longer and more variable fragment of 702 bp). For both genomic fragments, phylogenetic trees showed the absence of lineages within RNV group, and a close genetic relationship between Argentinean strains and the prototype strain BeAr35645 for PIXV clade. The analysis of nsP4 gene opens the possibility to propose a possible geographic clustering of strains within PIXV group (Argentina and Brazil). Coalescent analysis performed on RNV sequences suggested a common ancestor of 58.3 years (with a 95% highest posterior density [HPD] interval of 16.4-345.7) prior to 1991 and inferred a substitution rate of 9.8×10(-5)substitutions/site/year, slightly lower than other enzootic VEE viruses. These results provide, for the first time, information about genetic features and variability of all VEEVs detected in Argentina, creating a database that will be useful for future detections in our country. This is particularly important for RNV, which has indigenous circulation.
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Affiliation(s)
- María Belén Pisano
- Instituto de Virología "Dr. J.M. Vanella", Facultad de Ciencias Médicas, Universidad Nacional de Córdoba (UNC), Enfermera Gordillo Gómez s/n, Ciudad Universitaria, X5016 Córdoba, Argentina.
| | - Carolina Torres
- Cátedra de Virología, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires (UBA), Junín 956, 4° piso, C1113AAD Buenos Aires, Argentina
| | - Viviana Elizabeth Ré
- Instituto de Virología "Dr. J.M. Vanella", Facultad de Ciencias Médicas, Universidad Nacional de Córdoba (UNC), Enfermera Gordillo Gómez s/n, Ciudad Universitaria, X5016 Córdoba, Argentina
| | - Adrián Alejandro Farías
- Instituto de Virología "Dr. J.M. Vanella", Facultad de Ciencias Médicas, Universidad Nacional de Córdoba (UNC), Enfermera Gordillo Gómez s/n, Ciudad Universitaria, X5016 Córdoba, Argentina
| | - María Paz Sánchez Seco
- Centro Nacional de Microbiología, Instituto de Salud Carlos III, Carretera Pozuelo Km 2, E28220 Majadahonda, Madrid, Spain
| | - Antonio Tenorio
- Centro Nacional de Microbiología, Instituto de Salud Carlos III, Carretera Pozuelo Km 2, E28220 Majadahonda, Madrid, Spain
| | - Rodolfo Campos
- Cátedra de Virología, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires (UBA), Junín 956, 4° piso, C1113AAD Buenos Aires, Argentina
| | - Marta Silvia Contigiani
- Instituto de Virología "Dr. J.M. Vanella", Facultad de Ciencias Médicas, Universidad Nacional de Córdoba (UNC), Enfermera Gordillo Gómez s/n, Ciudad Universitaria, X5016 Córdoba, Argentina
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19
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Go YY, Balasuriya UBR, Lee CK. Zoonotic encephalitides caused by arboviruses: transmission and epidemiology of alphaviruses and flaviviruses. Clin Exp Vaccine Res 2013; 3:58-77. [PMID: 24427764 PMCID: PMC3890452 DOI: 10.7774/cevr.2014.3.1.58] [Citation(s) in RCA: 127] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2013] [Revised: 10/03/2013] [Accepted: 10/20/2013] [Indexed: 12/29/2022] Open
Abstract
In this review, we mainly focus on zoonotic encephalitides caused by arthropod-borne viruses (arboviruses) of the families Flaviviridae (genus Flavivirus) and Togaviridae (genus Alphavirus) that are important in both humans and domestic animals. Specifically, we will focus on alphaviruses (Eastern equine encephalitis virus, Western equine encephalitis virus, Venezuelan equine encephalitis virus) and flaviviruses (Japanese encephalitis virus and West Nile virus). Most of these viruses were originally found in tropical regions such as Africa and South America or in some regions in Asia. However, they have dispersed widely and currently cause diseases around the world. Global warming, increasing urbanization and population size in tropical regions, faster transportation and rapid spread of arthropod vectors contribute in continuous spreading of arboviruses into new geographic areas causing reemerging or resurging diseases. Most of the reemerging arboviruses also have emerged as zoonotic disease agents and created major public health issues and disease epidemics.
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Affiliation(s)
- Yun Young Go
- Virus Research and Testing Group, Division of Drug Discovery Research, Korea Research Institute of Chemical Technology, Daejeon, Korea
| | - Udeni B R Balasuriya
- Maxwell H. Gluck Equine Research Center, Department of Veterinary Science, College of Agriculture, Food and Environment, University of Kentucky, Lexington, KY, USA. ; Department of Microbiology, Immunology and Molecular Genetics, College of Medicine, University of Kentucky, Lexington, KY, USA
| | - Chong-Kyo Lee
- Virus Research and Testing Group, Division of Drug Discovery Research, Korea Research Institute of Chemical Technology, Daejeon, Korea
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Pisano MB, Oria G, Beskow G, Aguilar J, Konigheim B, Cacace ML, Aguirre L, Stein M, Contigiani MS. Venezuelan equine encephalitis viruses (VEEV) in Argentina: serological evidence of human infection. PLoS Negl Trop Dis 2013; 7:e2551. [PMID: 24349588 PMCID: PMC3861189 DOI: 10.1371/journal.pntd.0002551] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2013] [Accepted: 10/07/2013] [Indexed: 11/19/2022] Open
Abstract
Venezuelan equine encephalitis viruses (VEEV) are responsible for human diseases in the Americas, producing severe or mild illness with symptoms indistinguishable from dengue and other arboviral diseases. For this reason, many cases remain without certain diagnosis. Seroprevalence studies for VEEV subtypes IAB, ID, IF (Mosso das Pedras virus; MDPV), IV (Pixuna virus; PIXV) and VI (Rio Negro virus; RNV) were conducted in persons from Northern provinces of Argentina: Salta, Chaco and Corrientes, using plaque reduction neutralization test (PRNT). RNV was detected in all studied provinces. Chaco presented the highest prevalence of this virus (14.1%). Antibodies against VEEV IAB and -for the first time- against MDPV and PIXV were also detected in Chaco province. In Corrientes, seroprevalence against RNV was 1.3% in the pediatric population, indicating recent infections. In Salta, this was the first investigation of VEEV members, and antibodies against RNV and PIXV were detected. These results provide evidence of circulation of many VEE viruses in Northern Argentina, showing that surveillance of these infectious agents should be intensified. Venezuelan equine encephalitis viruses (VEEV) are responsible for human diseases in the Americas. They produce severe or mild illnesses with symptoms indistinguishable from dengue and other arboviral diseases; for this reason, many cases remain undiagnosed. We detected neutralizing antibodies (NTAbs) against VEEV IAB, VEEV ID, MDPV (VEEV subtype IF), PIXV (VEEV subtype IV) and RNV (VEEV subtype VI) in human serum samples of Northern provinces of Argentina. Chaco province showed presence of NTAbs against VEEV IAB, MDPV, PIXV and RNV. In Corrientes province, we detected NTAbs against RNV in a pediatric population. NTAbs against PIXV and RNV were also detected in Salta province. These findings demonstrated the circulation of many VEEV strains in Northern Argentina and underscore the need for surveillance of dengue like illness in this region.
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Affiliation(s)
- María Belén Pisano
- Instituto de Virología “Dr. J. M. Vanella”, Facultad de Ciencias Médicas, Universidad Nacional de Córdoba, Enfermera Gordillo Gómez s/n, Ciudad Universitaria, Córdoba, Argentina
- * E-mail:
| | - Griselda Oria
- Instituto de Medicina Regional, Universidad Nacional del Nordeste, Resistencia, Chaco, Argentina
| | - Geraldine Beskow
- Instituto de Medicina Regional, Universidad Nacional del Nordeste, Resistencia, Chaco, Argentina
| | - Javier Aguilar
- Instituto de Virología “Dr. J. M. Vanella”, Facultad de Ciencias Médicas, Universidad Nacional de Córdoba, Enfermera Gordillo Gómez s/n, Ciudad Universitaria, Córdoba, Argentina
| | - Brenda Konigheim
- Instituto de Virología “Dr. J. M. Vanella”, Facultad de Ciencias Médicas, Universidad Nacional de Córdoba, Enfermera Gordillo Gómez s/n, Ciudad Universitaria, Córdoba, Argentina
| | | | - Luis Aguirre
- Hospital Dante Tardelli, Pampa del Indio, Chaco, Argentina
| | - Marina Stein
- Instituto de Medicina Regional, Universidad Nacional del Nordeste, Resistencia, Chaco, Argentina
| | - Marta Silvia Contigiani
- Instituto de Virología “Dr. J. M. Vanella”, Facultad de Ciencias Médicas, Universidad Nacional de Córdoba, Enfermera Gordillo Gómez s/n, Ciudad Universitaria, Córdoba, Argentina
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Guerbois M, Volkova E, Forrester NL, Rossi SL, Frolov I, Weaver SC. IRES-driven expression of the capsid protein of the Venezuelan equine encephalitis virus TC-83 vaccine strain increases its attenuation and safety. PLoS Negl Trop Dis 2013; 7:e2197. [PMID: 23675542 PMCID: PMC3649961 DOI: 10.1371/journal.pntd.0002197] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2012] [Accepted: 03/26/2013] [Indexed: 01/04/2023] Open
Abstract
The live-attenuated TC-83 strain is the only licensed veterinary vaccine available to protect equids against Venezuelan equine encephalitis virus (VEEV) and to protect humans indirectly by preventing equine amplification. However, TC-83 is reactogenic due to its reliance on only two attenuating point mutations and has infected mosquitoes following equine vaccination. To increase its stability and safety, a recombinant TC-83 was previously engineered by placing the expression of the viral structural proteins under the control of the Internal Ribosome Entry Site (IRES) of encephalomyocarditis virus (EMCV), which drives translation inefficiently in insect cells. However, this vaccine candidate was poorly immunogenic. Here we describe a second generation of the recombinant TC-83 in which the subgenomic promoter is maintained and only the capsid protein gene is translated from the IRES. This VEEV/IRES/C vaccine candidate did not infect mosquitoes, was stable in its attenuation phenotype after serial murine passages, and was more attenuated in newborn mice but still as protective as TC-83 against VEEV challenge. Thus, by using the IRES to modulate TC-83 capsid protein expression, we generated a vaccine candidate that combines efficient immunogenicity and efficacy with lower virulence and a reduced potential for spread in nature. Venezuelan equine encephalitis virus (VEEV) is transmitted by mosquitoes and widely distributed in Central and South America, causing regular outbreaks in horses and humans. Often misdiagnosed as dengue, VEEV infection in humans can lead to lifelong neurological sequelae and is fatal in up to >80% of equine cases, representing a significant socio-economic burden and constant public health threats for developing countries of Latin America. The only available vaccine, the live-attenuated TC-83 strain, is restricted to veterinary use due to its high reactogenicity in humans and risk for reversion to virulence, which could initiate an epidemic. By using an attenuation approach that allows the modulation of the virus capsid protein expression, we generated a new version of TC-83 that is more attenuated but still induces a protective immune response in mice. Additionally, this new vaccine cannot infect mosquitoes, which prevents the risk of spreading in nature. The attenuation approach we describe can be applied to a lot of other alphaviruses to develop vaccines against diseases regularly emerging and threatening developing countries.
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MESH Headings
- Aedes
- Animals
- Capsid Proteins/biosynthesis
- Capsid Proteins/genetics
- Cell Line
- Chlorocebus aethiops
- Disease Models, Animal
- Encephalitis Virus, Venezuelan Equine/genetics
- Encephalitis Virus, Venezuelan Equine/immunology
- Encephalitis Virus, Venezuelan Equine/pathogenicity
- Encephalomyelitis, Venezuelan Equine/immunology
- Encephalomyelitis, Venezuelan Equine/prevention & control
- Gene Expression
- Genomic Instability
- Humans
- Mice
- Protein Biosynthesis
- Survival Analysis
- Vaccines, Attenuated/administration & dosage
- Vaccines, Attenuated/adverse effects
- Vaccines, Attenuated/genetics
- Vaccines, Attenuated/immunology
- Vaccines, Synthetic/administration & dosage
- Vaccines, Synthetic/adverse effects
- Vaccines, Synthetic/genetics
- Vaccines, Synthetic/immunology
- Viral Vaccines/administration & dosage
- Viral Vaccines/adverse effects
- Viral Vaccines/genetics
- Viral Vaccines/immunology
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Affiliation(s)
- Mathilde Guerbois
- Institute for Human Infections and Immunity, Sealy Center for Vaccine Development, and Department of Pathology, University of Texas Medical Branch, Galveston, Texas, United States of America
| | - Eugenia Volkova
- Institute for Human Infections and Immunity, Sealy Center for Vaccine Development, and Department of Pathology, University of Texas Medical Branch, Galveston, Texas, United States of America
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, Texas, United States of America
| | - Naomi L. Forrester
- Institute for Human Infections and Immunity, Sealy Center for Vaccine Development, and Department of Pathology, University of Texas Medical Branch, Galveston, Texas, United States of America
| | - Shannan L. Rossi
- Institute for Human Infections and Immunity, Sealy Center for Vaccine Development, and Department of Pathology, University of Texas Medical Branch, Galveston, Texas, United States of America
| | - Ilya Frolov
- Institute for Human Infections and Immunity, Sealy Center for Vaccine Development, and Department of Pathology, University of Texas Medical Branch, Galveston, Texas, United States of America
| | - Scott C. Weaver
- Institute for Human Infections and Immunity, Sealy Center for Vaccine Development, and Department of Pathology, University of Texas Medical Branch, Galveston, Texas, United States of America
- * E-mail:
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Rülker T, Voß L, Thullier P, O' Brien LM, Pelat T, Perkins SD, Langermann C, Schirrmann T, Dübel S, Marschall HJ, Hust M, Hülseweh B. Isolation and characterisation of a human-like antibody fragment (scFv) that inactivates VEEV in vitro and in vivo. PLoS One 2012; 7:e37242. [PMID: 22666347 PMCID: PMC3364240 DOI: 10.1371/journal.pone.0037242] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2011] [Accepted: 04/18/2012] [Indexed: 11/18/2022] Open
Abstract
Venezuelan equine encephalitis virus (VEEV) belongs to the Alphavirus genus and several species of this family are pathogenic to humans. The viruses are classified as potential agents of biological warfare and terrorism and sensitive detection as well as effective prophylaxis and antiviral therapies are required.In this work, we describe the isolation of the anti-VEEV single chain Fragment variable (scFv), ToR67-3B4, from a non-human primate (NHP) antibody gene library. We report its recloning into the bivalent scFv-Fc format and further immunological and biochemical characterisation.The scFv-Fc ToR67-3B4 recognised viable as well as formalin and ß-propionolactone (ß-Pl) inactivated virus particles and could be applied for immunoblot analysis of VEEV proteins and immuno-histochemistry of VEEV infected cells. It detected specifically the viral E1 envelope protein of VEEV but did not react with reduced viral glycoprotein preparations suggesting that recognition depends upon conformational epitopes. The recombinant antibody was able to detect multiple VEEV subtypes and displayed only marginal cross-reactivity to other Alphavirus species except for EEEV. In addition, the scFv-Fc fusion described here might be of therapeutic use since it successfully inactivated VEEV in a murine disease model. When the recombinant antibody was administered 6 hours post challenge, 80% to 100% of mice survived lethal VEEV IA/B or IE infection. Forty to sixty percent of mice survived when scFv-Fc ToR67-3B4 was applied 6 hours post challenge with VEEV subtypes II and former IIIA. In combination with E2-neutralising antibodies the NHP antibody isolated here could significantly improve passive protection as well as generic therapy of VEE.
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MESH Headings
- Animals
- Antibodies, Neutralizing/genetics
- Antibodies, Neutralizing/immunology
- Antibodies, Neutralizing/isolation & purification
- Antibodies, Viral/genetics
- Antibodies, Viral/immunology
- Antibodies, Viral/isolation & purification
- Cloning, Molecular
- Encephalitis Virus, Venezuelan Equine/immunology
- Gene Library
- Genetic Vectors/genetics
- Humans
- Immunization, Passive
- Macaca fascicularis
- Male
- Mice
- Mice, Inbred BALB C
- Recombinant Fusion Proteins/genetics
- Recombinant Fusion Proteins/immunology
- Recombinant Fusion Proteins/isolation & purification
- Sequence Analysis
- Single-Chain Antibodies/genetics
- Single-Chain Antibodies/immunology
- Single-Chain Antibodies/isolation & purification
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Affiliation(s)
- Torsten Rülker
- Technische Universität Braunschweig, Institut für Biochemie und Biotechnologie, Braunschweig, Germany
| | - Luzie Voß
- Wehrwissenschaftliches Institut für Schutztechnologien (WIS) – ABC-Schutz, Munster, Germany
| | - Philippe Thullier
- Centre de Recherche du Service de Santé des Armées (CRSSA-IRBA), La Tronche, France
| | - Lyn M. O' Brien
- Defence Science and Technology Laboratory, Biomedical Sciences Department, Porton Down, Salisbury, Wiltshire, United Kingdom
| | - Thibaut Pelat
- Centre de Recherche du Service de Santé des Armées (CRSSA-IRBA), La Tronche, France
| | - Stuart D. Perkins
- Defence Science and Technology Laboratory, Biomedical Sciences Department, Porton Down, Salisbury, Wiltshire, United Kingdom
| | - Claudia Langermann
- Wehrwissenschaftliches Institut für Schutztechnologien (WIS) – ABC-Schutz, Munster, Germany
| | - Thomas Schirrmann
- Technische Universität Braunschweig, Institut für Biochemie und Biotechnologie, Braunschweig, Germany
| | - Stefan Dübel
- Technische Universität Braunschweig, Institut für Biochemie und Biotechnologie, Braunschweig, Germany
| | - Hans-Jürgen Marschall
- Wehrwissenschaftliches Institut für Schutztechnologien (WIS) – ABC-Schutz, Munster, Germany
| | - Michael Hust
- Technische Universität Braunschweig, Institut für Biochemie und Biotechnologie, Braunschweig, Germany
| | - Birgit Hülseweh
- Wehrwissenschaftliches Institut für Schutztechnologien (WIS) – ABC-Schutz, Munster, Germany
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23
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Specific detection of all members of the Venezuelan Equine Encephalitis complex: development of a RT-Nested PCR. J Virol Methods 2012; 186:203-6. [PMID: 22609888 DOI: 10.1016/j.jviromet.2012.05.009] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2011] [Revised: 05/04/2012] [Accepted: 05/10/2012] [Indexed: 11/21/2022]
Abstract
Venezuelan Equine Encephalitis (VEE) complex belongs to alphavirus genus in the family Togaviridae. Several species of this complex are pathogenic to humans. VEE infections can produce severe or mild disease, and many cases remain undiagnosed. A specific and sensitive reverse transcriptase nested polymerase chain reaction (RT-Nested PCR) method was developed for the detection of all VEE subtypes, including Rio Negro Virus (RNV) (subtype VI), which circulates only in Argentina. Degenerated primers were designed and thermal cycling parameters were standardized. This technique is suitable for rapid and specific detection of these viruses, and may be useful for diagnosis and surveillance.
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24
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Stahl JP, Mailles A, Dacheux L, Morand P. Epidemiology of viral encephalitis in 2011. Med Mal Infect 2011; 41:453-64. [PMID: 21802875 DOI: 10.1016/j.medmal.2011.05.015] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2011] [Accepted: 05/27/2011] [Indexed: 01/17/2023]
Abstract
Encephalitis is an inflammation of the brain structures: neurons, vessels or glial cells. However, a consensual definition of the syndrome is difficult to obtain, and it is even more difficult to define encephalitis due a specific agent. Most viruses can be responsible for infectious encephalitis, but the number of encephalitis cases is very limited with regards of the incidence of benign infections from these pathogens. Viruses responsible for encephalitis can be animal-borne, vector-borne or human-to-human transmitted, they can infect preferentially immunocompetent or immunosuppressed patients, and some of them have demonstrated their epidemic potential. Herpes simplex encephalitis is recognized worldwide as the most frequent infectious encephalitis, and the only one with a validated specific treatment. Encephalitis following some viral infections such as measles or rabies can be prevented by vaccination. Unfortunately, effective treatment currently lacks for most encephalitic viral agents identified so far.
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Affiliation(s)
- J-P Stahl
- Tropical and Infectious Diseases, université Joseph-Fourier Grenoble 1, CHU de Grenoble, Grenoble, France
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25
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Aguilar PV, Estrada-Franco JG, Navarro-Lopez R, Ferro C, Haddow AD, Weaver SC. Endemic Venezuelan equine encephalitis in the Americas: hidden under the dengue umbrella. Future Virol 2011. [DOI: 10.2217/fvl.11.50] [Citation(s) in RCA: 108] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Venezuelan equine encephalitis (VEE) is an emerging infectious disease in Latin America. Outbreaks have been recorded for decades in countries with enzootic circulation, and the recent implementation of surveillance systems has allowed the detection of additional human cases in countries and areas with previously unknown VEE activity. Clinically, VEE is indistinguishable from dengue and other arboviral diseases and confirmatory diagnosis requires the use of specialized laboratory tests that are difficult to afford in resource-limited regions. Thus, the disease burden of endemic VEE in developing countries remains largely unknown, but recent surveillance suggests that it may represent up to 10% of the dengue burden in neotropical cities, or tens-of-thousands of cases per year throughout Latin America. The potential emergence of epizootic viruses from enzootic progenitors further highlights the need to strengthen surveillance activities, identify mosquito vectors and reservoirs and develop effective strategies to control the disease. In this article, we provide an overview of the current status of endemic VEE that results from spillover of the enzootic cycles, and we discuss public health measures for disease control as well as future avenues for VEE research.
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Affiliation(s)
- Patricia V Aguilar
- Center for Tropical Diseases, Institute for Human Infections & Immunity, University of Texas Medical Branch, Galveston, TX, USA
- Department of Pathology, University of Texas Medical Branch, Galveston, TX, USA
| | - Jose G Estrada-Franco
- Center for Tropical Diseases, Institute for Human Infections & Immunity, University of Texas Medical Branch, Galveston, TX, USA
- Department of Pathology, University of Texas Medical Branch, Galveston, TX, USA
| | - Roberto Navarro-Lopez
- Comision Mexico-Estados Unidos para la Prevencion de la Fiebre Aftosa & Otras Enfermedades Exoticas de los Animales, Mexico City, Mexico
| | | | - Andrew D Haddow
- Center for Tropical Diseases, Institute for Human Infections & Immunity, University of Texas Medical Branch, Galveston, TX, USA
- Department of Pathology, University of Texas Medical Branch, Galveston, TX, USA
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26
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Aguilar PV, Estrada-Franco JG, Navarro-Lopez R, Ferro C, Haddow AD, Weaver SC. Endemic Venezuelan equine encephalitis in the Americas: hidden under the dengue umbrella. Future Virol 2011; 6:721-740. [PMID: 21765860 DOI: 10.2217/fvl.11.5] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Venezuelan equine encephalitis (VEE) is an emerging infectious disease in Latin America. Outbreaks have been recorded for decades in countries with enzootic circulation, and the recent implementation of surveillance systems has allowed the detection of additional human cases in countries and areas with previously unknown VEE activity. Clinically, VEE is indistinguishable from dengue and other arboviral diseases and confirmatory diagnosis requires the use of specialized laboratory tests that are difficult to afford in resource-limited regions. Thus, the disease burden of endemic VEE in developing countries remains largely unknown, but recent surveillance suggests that it may represent up to 10% of the dengue burden in neotropical cities, or tens-of-thousands of cases per year throughout Latin America. The potential emergence of epizootic viruses from enzootic progenitors further highlights the need to strengthen surveillance activities, identify mosquito vectors and reservoirs and develop effective strategies to control the disease. In this article, we provide an overview of the current status of endemic VEE that results from spillover of the enzootic cycles, and we discuss public health measures for disease control as well as future avenues for VEE research.
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Affiliation(s)
- Patricia V Aguilar
- Center for Tropical Diseases, Institute for Human Infections & Immunity, University of Texas Medical Branch, Galveston, TX, USA
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27
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Pisano MB, Dantur MJ, Ré VE, Díaz LA, Farías A, Sánchez Seco MP, Tenorio A, Almirón WR, Contigiani MS. Cocirculation of Rio Negro Virus (RNV) and Pixuna Virus (PIXV) in Tucumán province, Argentina. Trop Med Int Health 2010; 15:865-8. [PMID: 20497404 DOI: 10.1111/j.1365-3156.2010.02541.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Venezuelan equine encephalitis complex includes viruses considered emerging pathogens for humans and animals in the Americas. Two members of this complex have been detected previously in Argentina: Rio Negro Virus (RNV), detected in mosquitoes from Chaco province and rodents from Formosa province, and Pixuna Virus (PIXV), detected in mosquitoes from Chaco province. To carry out surveillance studies in other parts of the country, detection of a 195-bp fragment of alphaviruses by RT-nested PCR was performed in mosquito samples from San Miguel de Tucumán city. Four pools resulted positive and three were sequenced. Two amplicons grouped with RNV and one with PIXV. This is the first report of viral activity of members of the Venezuelan equine encephalitis complex in north-eastern Argentina.
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Affiliation(s)
- M B Pisano
- Instituto de Virología Dr. J.M. Vanella, Facultad Ciencias Médicas, Universidad Nacional de Córdoba, Córdoba, Argentina.
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28
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Atasheva S, Fish A, Fornerod M, Frolova EI. Venezuelan equine Encephalitis virus capsid protein forms a tetrameric complex with CRM1 and importin alpha/beta that obstructs nuclear pore complex function. J Virol 2010; 84:4158-71. [PMID: 20147401 PMCID: PMC2863722 DOI: 10.1128/jvi.02554-09] [Citation(s) in RCA: 93] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2009] [Accepted: 01/31/2010] [Indexed: 12/25/2022] Open
Abstract
Development of the cellular antiviral response requires nuclear translocation of multiple transcription factors and activation of a wide variety of cellular genes. To counteract the antiviral response, several viruses have developed an efficient means of inhibiting nucleocytoplasmic traffic. In this study, we demonstrate that the pathogenic strain of Venezuelan equine encephalitis virus (VEEV) has developed a unique mechanism of nuclear import inhibition. Its capsid protein forms a tetrameric complex with the nuclear export receptor CRM1 and the nuclear import receptor importin alpha/beta. This unusual complex accumulates in the center channel of the nuclear pores and blocks nuclear import mediated by different karyopherins. The inhibitory function of VEEV capsid protein is determined by a short 39-amino-acid-long peptide that contains both nuclear import and supraphysiological nuclear export signals. Mutations in these signals or in the linker peptide attenuate or completely abolish capsid-specific inhibition of nuclear traffic. The less pathogenic VEEV strains contain a wide variety of mutations in this peptide that affect its inhibitory function in nuclear import. Thus, these mutations appear to be the determinants of this attenuated phenotype. This novel mechanism of inhibiting nuclear transport also shows that the nuclear pore complex is vulnerable to unusual cargo receptor complexes and sheds light on the importance of finely adjusted karyopherin-nucleoporin interactions for efficient cargo translocation.
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Affiliation(s)
- Svetlana Atasheva
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, Alabama 35294-2170, Netherlands Cancer Institute Proteomics Center, Division of Gene Regulation, Plesmanlaan 121, 1066CX Amsterdam, Netherlands
| | - Alexander Fish
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, Alabama 35294-2170, Netherlands Cancer Institute Proteomics Center, Division of Gene Regulation, Plesmanlaan 121, 1066CX Amsterdam, Netherlands
| | - Maarten Fornerod
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, Alabama 35294-2170, Netherlands Cancer Institute Proteomics Center, Division of Gene Regulation, Plesmanlaan 121, 1066CX Amsterdam, Netherlands
| | - Elena I. Frolova
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, Alabama 35294-2170, Netherlands Cancer Institute Proteomics Center, Division of Gene Regulation, Plesmanlaan 121, 1066CX Amsterdam, Netherlands
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29
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Pisano MB, Ré VE, Díaz LA, Farías A, Stein M, Sanchez-Seco MP, Tenorio A, Almirón WR, Contigiani MS. Enzootic Activity of Pixuna and Rio Negro Viruses (Venezuelan Equine Encephalitis complex) in a Neotropical Region of Argentina. Vector Borne Zoonotic Dis 2010; 10:199-201. [DOI: 10.1089/vbz.2008.0156] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- María Belén Pisano
- Instituto de Virología “Dr. J.M.Vanella,” Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Viviana Elizabeth Ré
- Instituto de Virología “Dr. J.M.Vanella,” Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Luis Adrián Díaz
- Instituto de Virología “Dr. J.M.Vanella,” Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Adrián Farías
- Instituto de Virología “Dr. J.M.Vanella,” Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Marina Stein
- Instituto de Medicina Regional, Universidad Nacional del Nordeste, Chaco, Argentina
| | | | | | - Walter Ricardo Almirón
- Centro Investigaciones Entomológicas de Córdoba, Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Marta Silvia Contigiani
- Instituto de Virología “Dr. J.M.Vanella,” Universidad Nacional de Córdoba, Córdoba, Argentina
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Weaver SC, Reisen WK. Present and future arboviral threats. Antiviral Res 2010; 85:328-45. [PMID: 19857523 PMCID: PMC2815176 DOI: 10.1016/j.antiviral.2009.10.008] [Citation(s) in RCA: 912] [Impact Index Per Article: 65.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2009] [Revised: 10/01/2009] [Accepted: 10/16/2009] [Indexed: 11/20/2022]
Abstract
Arthropod-borne viruses (arboviruses) are important causes of human disease nearly worldwide. All arboviruses circulate among wild animals, and many cause disease after spillover transmission to humans and agriculturally important domestic animals that are incidental or dead-end hosts. Viruses such as dengue (DENV) and chikungunya (CHIKV) that have lost the requirement for enzootic amplification now produce extensive epidemics in tropical urban centers. Many arboviruses recently have increased in importance as human and veterinary pathogens using a variety of mechanisms. Beginning in 1999, West Nile virus (WNV) underwent a dramatic geographic expansion into the Americas. High amplification associated with avian virulence coupled with adaptation for replication at higher temperatures in mosquito vectors, has caused the largest epidemic of arboviral encephalitis ever reported in the Americas. Japanese encephalitis virus (JEV), the most frequent arboviral cause of encephalitis worldwide, has spread throughout most of Asia and as far south as Australia from its putative origin in Indonesia and Malaysia. JEV has caused major epidemics as it invaded new areas, often enabled by rice culture and amplification in domesticated swine. Rift Valley fever virus (RVFV), another arbovirus that infects humans after amplification in domesticated animals, undergoes epizootic transmission during wet years following droughts. Warming of the Indian Ocean, linked to the El Niño-Southern Oscillation in the Pacific, leads to heavy rainfall in east Africa inundating surface pools and vertically infected mosquito eggs laid during previous seasons. Like WNV, JEV and RVFV could become epizootic and epidemic in the Americas if introduced unintentionally via commerce or intentionally for nefarious purposes. Climate warming also could facilitate the expansion of the distributions of many arboviruses, as documented for bluetongue viruses (BTV), major pathogens of ruminants. BTV, especially BTV-8, invaded Europe after climate warming and enabled the major midge vector to expand is distribution northward into southern Europe, extending the transmission season and vectorial capacity of local midge species. Perhaps the greatest health risk of arboviral emergence comes from extensive tropical urbanization and the colonization of this expanding habitat by the highly anthropophilic (attracted to humans) mosquito, Aedes aegypti. These factors led to the emergence of permanent endemic cycles of urban DENV and CHIKV, as well as seasonal interhuman transmission of yellow fever virus. The recent invasion into the Americas, Europe and Africa by Aedes albopictus, an important CHIKV and secondary DENV vector, could enhance urban transmission of these viruses in tropical as well as temperate regions. The minimal requirements for sustained endemic arbovirus transmission, adequate human viremia and vector competence of Ae. aegypti and/or Ae. albopictus, may be met by two other viruses with the potential to become major human pathogens: Venezuelan equine encephalitis virus, already an important cause of neurological disease in humans and equids throughout the Americas, and Mayaro virus, a close relative of CHIKV that produces a comparably debilitating arthralgic disease in South America. Further research is needed to understand the potential of these and other arboviruses to emerge in the future, invade new geographic areas, and become important public and veterinary health problems.
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Affiliation(s)
- Scott C Weaver
- Department of Pathology and Center for Biodefense and Emerging Infectious Diseases, University of Texas Medical Branch, Galveston, TX 77555-0609, USA.
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31
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Aguilar PV, Adams AP, Suárez V, Beingolea L, Vargas J, Manock S, Freire J, Espinoza WR, Felices V, Diaz A, Liang X, Roca Y, Weaver SC, Kochel TJ. Genetic characterization of Venezuelan equine encephalitis virus from Bolivia, Ecuador and Peru: identification of a new subtype ID lineage. PLoS Negl Trop Dis 2009; 3:e514. [PMID: 19753102 PMCID: PMC2734058 DOI: 10.1371/journal.pntd.0000514] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2009] [Accepted: 08/18/2009] [Indexed: 11/22/2022] Open
Abstract
Venezuelan equine encephalitis virus (VEEV) has been responsible for hundreds of thousands of human and equine cases of severe disease in the Americas. A passive surveillance study was conducted in Peru, Bolivia and Ecuador to determine the arboviral etiology of febrile illness. Patients with suspected viral-associated, acute, undifferentiated febrile illness of <7 days duration were enrolled in the study and blood samples were obtained from each patient and assayed by virus isolation. Demographic and clinical information from each patient was also obtained at the time of voluntary enrollment. In 2005–2007, cases of Venezuelan equine encephalitis (VEE) were diagnosed for the first time in residents of Bolivia; the patients did not report traveling, suggesting endemic circulation of VEEV in Bolivia. In 2001 and 2003, VEE cases were also identified in Ecuador. Since 1993, VEEV has been continuously isolated from patients in Loreto, Peru, and more recently (2005), in Madre de Dios, Peru. We performed phylogenetic analyses with VEEV from Bolivia, Ecuador and Peru and compared their relationships to strains from other parts of South America. We found that VEEV subtype ID Panama/Peru genotype is the predominant one circulating in Peru. We also demonstrated that VEEV subtype ID strains circulating in Ecuador belong to the Colombia/Venezuela genotype and VEEV from Madre de Dios, Peru and Cochabamba, Bolivia belong to a new ID genotype. In summary, we identified a new major lineage of enzootic VEEV subtype ID, information that could aid in the understanding of the emergence and evolution of VEEV in South America. Venezuelan equine encephalitis virus (VEEV) has been responsible for hundreds of thousands of human and equine cases of severe disease in the Americas. In 2005–2007, cases of Venezuelan equine encephalitis (VEE) were diagnosed for the first time in residents of Bolivia; the patients did not report traveling, suggesting endemic circulation of VEEV in Bolivia. In 2001 and 2003, VEE cases were also identified in Ecuador. We characterize recent VEEV from Bolivia, Ecuador and Peru and compared their relationships to strains from other parts of South America. We found that most VEEV from Peru grouped within a particular genetic lineage known to circulate in Panama and Peru whereas the VEEV circulating in Ecuador belong to a genetic lineage that circulates in Colombia and Venezuela. Importantly, the VEEV from Madre de Dios, Peru and Cochabamba, Bolivia belong to a new genetic lineage. This finding could aid in the understanding of the emergence and evolution of VEEV in South America and underscores the need for continuous monitoring for VEEV activity.
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Affiliation(s)
| | - A. Paige Adams
- Department of Pathology and Center for Tropical Diseases, University of Texas Medical Branch, Galveston, Texas, United States of America
| | | | | | - Jorge Vargas
- Centro de Enfermedades Tropicales, Santa Cruz, Bolivia
| | | | - Juan Freire
- Hospital de la IV División de Amazonas, Puyo, Ecuador
| | | | - Vidal Felices
- Naval Medical Research Center Detachment, Lima, Peru
| | - Ana Diaz
- Facultad de Ciencias, Universidad Nacional Agraria La Molina, Lima, Peru
| | - Xiaodong Liang
- Department of Pathology and Center for Tropical Diseases, University of Texas Medical Branch, Galveston, Texas, United States of America
| | - Yelin Roca
- Centro de Enfermedades Tropicales, Santa Cruz, Bolivia
| | - Scott C. Weaver
- Department of Pathology and Center for Tropical Diseases, University of Texas Medical Branch, Galveston, Texas, United States of America
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Venezuelan equine encephalitis in Panama: fatal endemic disease and genetic diversity of etiologic viral strains. PLoS Negl Trop Dis 2009; 3:e472. [PMID: 19564908 PMCID: PMC2697379 DOI: 10.1371/journal.pntd.0000472] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2009] [Accepted: 05/28/2009] [Indexed: 11/21/2022] Open
Abstract
Venezuelan equine encephalitis (VEE) is a reemerging, mosquito-borne viral disease of the neotropics that is severely debilitating and sometimes fatal to humans. Periodic epidemics mediated by equine amplification have been recognized since the 1920s, but interepidemic disease is rarely recognized. We report here clinical findings and genetic characterization of 42 cases of endemic VEE detected in Panama from 1961–2004. Recent clusters of cases occurred in Darien (eastern Panama) and Panama provinces (central Panama) near rainforest and swamp habitats. Patients ranged from 10 months to 48 years of age, and the more severe cases with neurological complications, including one fatal infection, were observed in children. The VEE virus strains isolated from these cases all belonged to an enzootic, subtype ID lineage known to circulate among sylvatic vectors and rodent reservoir hosts in Panama and Peru. These findings underscore endemic VEE as an important but usually neglected arboviral disease of Latin America. Venezuelan equine encephalitis (VEE) is a mosquito-borne viral disease that has caused major epidemics in many parts of Latin America and has even spread into Texas on one occasion. These epidemics result from spillover to humans of a horse-mosquito-horse amplification cycle that has occurred periodically since the 1920s. However, between these equine-mediated epidemics, little attempt is typically made to detect VEE in humans. Here, we show that VEE virus strains that typically circulate in a mosquito-rodent cycle, termed enzootic strains, also produce many cases of severe and sometimes fatal disease in Panama in the absence of apparent epidemics. These endemic infections are probably rarely detected because they are difficult to distinguish clinically from dengue fever, another mosquito-borne viral illness common in the tropics. Our findings underscore endemic VEE as an important but usually neglected arboviral disease of Latin America.
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Morrison AC, Forshey BM, Notyce D, Astete H, Lopez V, Rocha C, Carrion R, Carey C, Eza D, Montgomery JM, Kochel TJ. Venezuelan equine encephalitis virus in Iquitos, Peru: urban transmission of a sylvatic strain. PLoS Negl Trop Dis 2008; 2:e349. [PMID: 19079600 PMCID: PMC2593782 DOI: 10.1371/journal.pntd.0000349] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2008] [Accepted: 11/18/2008] [Indexed: 11/29/2022] Open
Abstract
Enzootic strains of Venezuelan equine encephalitis virus (VEEV) have been isolated from febrile patients in the Peruvian Amazon Basin at low but consistent levels since the early 1990s. Through a clinic-based febrile surveillance program, we detected an outbreak of VEEV infections in Iquitos, Peru, in the first half of 2006. The majority of these patients resided within urban areas of Iquitos, with no report of recent travel outside the city. To characterize the risk factors for VEEV infection within the city, an antibody prevalence study was carried out in a geographically stratified sample of urban areas of Iquitos. Additionally, entomological surveys were conducted to determine if previously incriminated vectors of enzootic VEEV were present within the city. We found that greater than 23% of Iquitos residents carried neutralizing antibodies against VEEV, with significant associations between increased antibody prevalence and age, occupation, mosquito net use, and overnight travel. Furthermore, potential vector mosquitoes were widely distributed across the city. Our results suggest that while VEEV infection is more common in rural areas, transmission also occurs within urban areas of Iquitos, and that further studies are warranted to identify the precise vectors and reservoirs involved in urban VEEV transmission. Venezuelan equine encephalitis (VEE) is a mosquito-borne viral disease often causing grave illness and large outbreaks of disease in South America. In Iquitos, Peru, a city of 350,000 situated in the Amazon forest, we normally observe 10–14 VEE cases per year associated with people traveling to rural areas where strains VEE virus circulate among forest mosquitoes and rodents. In 2006 we detected a 5-fold increase in human VEE cases, and many of these patients had no travel history outside the city where they lived. In response to this outbreak, we decided to determine if potential carrier mosquitoes were present within the city and if city residents had been previously exposed to the virus. We found that mosquitoes previously shown to transmit the virus in other locations were present—in varying amounts based on location and time of year—throughout Iquitos. A large percentage of the human population (>23%) had antibodies indicating past exposure to the virus. Previous VEE infection was associated with age, occupation, mosquito exposure, and overnight travel. Our data represent evidence of transmission of a forest strain of VEE within a large urban area. Continued monitoring of this situation will shed light on mechanisms of virus emergence.
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Affiliation(s)
- Amy C Morrison
- Naval Medical Research Center Detachment, Iquitos and Lima, Peru.
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Kirsch MI, Hülseweh B, Nacke C, Rülker T, Schirrmann T, Marschall HJ, Hust M, Dübel S. Development of human antibody fragments using antibody phage display for the detection and diagnosis of Venezuelan equine encephalitis virus (VEEV). BMC Biotechnol 2008; 8:66. [PMID: 18764933 PMCID: PMC2543005 DOI: 10.1186/1472-6750-8-66] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2007] [Accepted: 09/02/2008] [Indexed: 01/06/2023] Open
Abstract
BACKGROUND Venezuelan equine encephalitis virus (VEEV) belongs to the Alphavirus group. Several species of this family are also pathogenic to humans and are recognized as potential agents of biological warfare and terrorism. The objective of this work was the generation of recombinant antibodies for the detection of VEEV after a potential bioterrorism assault or an natural outbreak of VEEV. RESULTS In this work, human anti-VEEV single chain Fragments variable (scFv) were isolated for the first time from a human naïve antibody gene library using optimized selection processes. In total eleven different scFvs were identified and their immunological specificity was assessed. The specific detection of the VEEV strains TC83, H12/93 and 230 by the selected antibody fragments was proved. Active as well as formalin inactivated virus particles were recognized by the selected antibody fragments which could be also used for Western blot analysis of VEEV proteins and immunohistochemistry of VEEV infected cells. The anti-VEEV scFv phage clones did not show any cross-reactivity with Alphavirus species of the Western equine encephalitis virus (WEEV) and Eastern equine encephalitis virus (EEEV) antigenic complex, nor did they react with Chikungunya virus (CHIKV), if they were used as detection reagent. CONCLUSION For the first time, this study describes the selection of antibodies against a human pathogenic virus from a human naïve scFv antibody gene library using complete, active virus particles as antigen. The broad and sensitive applicability of scFv-presenting phage for the immunological detection and diagnosis of Alphavirus species was demonstrated. The selected antibody fragments will improve the fast identification of VEEV in case of a biological warfare or terroristic attack or a natural outbreak.
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Affiliation(s)
- Martina Inga Kirsch
- Abteilung Biotechnologie, Institut für Biochemie und Biotechnologie, Technische Universität Braunschweig, Spielmannstraβe 7, 38106, Braunschweig, Germany
| | - Birgit Hülseweh
- Armed Forces Scientific Institute for Protection Technologies – NBC Protection (WIS), Humboldtstraße 1, 29633, Munster, Germany
| | - Christoph Nacke
- Abteilung Biotechnologie, Institut für Biochemie und Biotechnologie, Technische Universität Braunschweig, Spielmannstraβe 7, 38106, Braunschweig, Germany
| | - Torsten Rülker
- Abteilung Biotechnologie, Institut für Biochemie und Biotechnologie, Technische Universität Braunschweig, Spielmannstraβe 7, 38106, Braunschweig, Germany
| | - Thomas Schirrmann
- Abteilung Biotechnologie, Institut für Biochemie und Biotechnologie, Technische Universität Braunschweig, Spielmannstraβe 7, 38106, Braunschweig, Germany
| | - Hans-Jürgen Marschall
- Armed Forces Scientific Institute for Protection Technologies – NBC Protection (WIS), Humboldtstraße 1, 29633, Munster, Germany
| | - Michael Hust
- Abteilung Biotechnologie, Institut für Biochemie und Biotechnologie, Technische Universität Braunschweig, Spielmannstraβe 7, 38106, Braunschweig, Germany
| | - Stefan Dübel
- Abteilung Biotechnologie, Institut für Biochemie und Biotechnologie, Technische Universität Braunschweig, Spielmannstraβe 7, 38106, Braunschweig, Germany
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Carrara AS, Coffey LL, Aguilar PV, Moncayo AC, Da Rosa APT, Nunes MR, Tesh RB, Weaver SC. Venezuelan equine encephalitis virus infection of cotton rats. Emerg Infect Dis 2007; 13:1158-65. [PMID: 17953085 PMCID: PMC2828070 DOI: 10.3201/eid1308.061157] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Venezuelan equine encephalitis virus (VEEV) is an emerging pathogen of equids and humans, but infection of its rodent reservoir hosts has received little study. To determine whether responses to infection vary among geographic populations, we inoculated 3 populations of cotton rats with 2 enzootic VEEV strains (Co97-0054 [enzootic ID subtype] and 68U201 [enzootic IE subtype]). The 3 populations were offspring from wild-caught cotton rats collected in a VEE-enzootic area of south Florida, USA; wild-caught cotton rats from a non-VEE-enzootic area of Texas, USA; and commercially available (Harlan) colony-reared cotton rats from a non-VEE-enzootic region. Although each population had similar early viremia titers, no detectable disease developed in the VEE-sympatric Florida animals, but severe disease and death affected the Texas and Harlan animals. Our findings suggest that the geographic origins of cotton rats are important determinants of the outcome of VEE infection and reservoir potential of these rodents.
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Affiliation(s)
| | - Lark L. Coffey
- University of Texas Medical Branch, Galveston, Texas, USA
| | | | | | | | | | - Robert B. Tesh
- University of Texas Medical Branch, Galveston, Texas, USA
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Wang E, Paessler S, Aguilar PV, Carrara AS, Ni H, Greene IP, Weaver SC. Reverse transcription-PCR-enzyme-linked immunosorbent assay for rapid detection and differentiation of alphavirus infections. J Clin Microbiol 2006; 44:4000-8. [PMID: 16957044 PMCID: PMC1698312 DOI: 10.1128/jcm.00175-06] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Due to the lack of a rapid, simple, and inexpensive assay for detecting alphavirus infections, we combined a reverse transcription-PCR with an enzyme-linked immunosorbent assay (RT-PCR-ELISA) to identify human pathogenic alphaviruses that are endemic in the New World. By combining the sensitivity of PCR, the detection simplicity of ELISA, and the specificities of DNA probes, this method rapidly detected and differentiated closely related species and subtypes of several medically important alphaviruses. After an amplification using RT-PCR with primers targeting conserved sequences in the nonstructural protein 1 gene, sequence-specific, biotin-labeled probes targeted against Venezuelan, eastern, and western equine encephalitis or Mayaro virus genes were used for the detection of amplicons using ELISA. The assay is simple, fast, and easy to perform in an ordinary diagnostic laboratory or clinical setting. Nucleic acid derived from cell cultures infected with several alphaviruses, clinical specimens, and mosquito pools as well as frozen and paraffin-embedded animal tissues were detected and identified within 6 to 7 h in a sensitive and specific manner.
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Affiliation(s)
- Eryu Wang
- Center for Biodefense and Emerging Infectious Diseases, Department of Pathology, University of Texas Medical Branch, Galveston, Texas 77555-0609, USA
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Weaver SC. Host range, amplification and arboviral disease emergence. ARCHIVES OF VIROLOGY. SUPPLEMENTUM 2006:33-44. [PMID: 16358422 DOI: 10.1007/3-211-29981-5_4] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Etiologic agents of arboviral diseases are primarily zoonotic pathogens that are maintained in nature in cycles involving arthropod transmission among a variety of susceptible reservoir hosts. In the simplest form of human exposure, spillover occurs from the enzootic cycle when humans enter zoonotic foci and/or enzootic amplification increases circulation near humans. Examples include Eastern (EEEV) and Western equine encephalitis viruses (WEEV), as well as West Nile (WNV), St. Louis encephalitis (SLEV) and Yellow fever viruses. Spillover can involve direct transmission to humans by primary enzootic vectors (e.g. WNV, SLEV and WEEV) and/or bridge vectors with more catholic feeding preferences that include humans (e.g. EEEV). Some viruses, such as Rift Valley fever, Japanese encephalitis and Venezuelan equine encephalitis viruses (VEEV) undergo secondary amplification involving replication in livestock animals, resulting in greater levels of spillover to humans in rural settings. In the case of VEEV, secondary amplification involves equines and requires adaptive mutations in enzootic strains that allow for efficient viremia production. Two of the most important human arboviral pathogens, Yellow fever and dengue viruses (DENV), have gone one step further and adopted humans as their amplification hosts, allowing for urban disease. The ancestral forms of DENV, sylvatic viruses transmitted among nonhuman primate reservoir hosts by arboreal mosquitoes, adapted to efficiently infect the urban mosquito vectors Aedes aegypti and Ae. albopictus during the past few thousand years as civilizations arose. Comparative studies of the sylvatic and urban forms of DENV may elucidate the evolution of arboviral virulence and the prospects for DENV eradication should effective vaccines be implemented.
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Affiliation(s)
- S C Weaver
- Center for Biodefense and Emerging Infectious Diseases and Department of Pathology, University of Texas Medical Branch, Galveston, Texas 77555-0609, USA.
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Anishchenko M, Bowen RA, Paessler S, Austgen L, Greene IP, Weaver SC. Venezuelan encephalitis emergence mediated by a phylogenetically predicted viral mutation. Proc Natl Acad Sci U S A 2006; 103:4994-9. [PMID: 16549790 PMCID: PMC1458783 DOI: 10.1073/pnas.0509961103] [Citation(s) in RCA: 103] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
RNA viruses are notorious for their genetic plasticity and propensity to exploit new host-range opportunities, which can lead to the emergence of human disease epidemics such as severe acute respiratory syndrome, AIDS, dengue, and influenza. However, the mechanisms of host-range change involved in most of these viral emergences, particularly the genetic mechanisms of adaptation to new hosts, remain poorly understood. We studied the emergence of Venezuelan equine encephalitis virus (VEEV), an alphavirus pathogen of people and equines that has had severe health and economic effects in the Americas since the early 20th century. Between epidemics, VEE disappears for periods up to decades, and the viral source of outbreaks has remained enigmatic. Combined with phylogenetic analyses to predict mutations associated with a 1992-1993 epidemic, we used reverse genetic studies to identify an envelope glycoprotein gene mutation that mediated emergence. This mutation allowed an enzootic, equine-avirulent VEEV strain, which circulates among rodents in nearby forests to adapt for equine amplification. RNA viruses including alphaviruses exhibit high mutation frequencies. Therefore, ecological and epidemiological factors probably constrain the frequency of VEE epidemics more than the generation, via mutation, of amplification-competent (high equine viremia) virus strains. These results underscore the ability of RNA viruses to alter their host range, virulence, and epidemic potential via minor genetic changes. VEE also demonstrates the unpredictable risks to human health of anthropogenic changes such as the introduction of equines and humans into habitats that harbor zoonotic RNA viruses.
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Affiliation(s)
- Michael Anishchenko
- *Center for Biodefense and Emerging Infectious Diseases and Department of Pathology, University of Texas Medical Branch, Galveston, TX 77555-0609; and
| | - Richard A. Bowen
- Department of Biomedical Sciences, Colorado State University, Fort Collins, CO 80523
| | - Slobodan Paessler
- *Center for Biodefense and Emerging Infectious Diseases and Department of Pathology, University of Texas Medical Branch, Galveston, TX 77555-0609; and
| | - Laura Austgen
- Department of Biomedical Sciences, Colorado State University, Fort Collins, CO 80523
| | - Ivorlyne P. Greene
- *Center for Biodefense and Emerging Infectious Diseases and Department of Pathology, University of Texas Medical Branch, Galveston, TX 77555-0609; and
| | - Scott C. Weaver
- *Center for Biodefense and Emerging Infectious Diseases and Department of Pathology, University of Texas Medical Branch, Galveston, TX 77555-0609; and
- To whom correspondence should be addressed. E-mail:
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Navarro JC, Medina G, Vasquez C, Coffey LL, Wang E, Suárez A, Biord H, Salas M, Weaver SC. Postepizootic persistence of Venezuelan equine encephalitis virus, Venezuela. Emerg Infect Dis 2006; 11:1907-15. [PMID: 16485478 PMCID: PMC3367636 DOI: 10.3201/eid1112.050533] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Etiologic subtype IC of virus persists, 5 years after the major 1995 epidemic. Five years after the apparent end of the major 1995 Venezuelan equine encephalitis (VEE) epizootic/epidemic, focal outbreaks of equine encephalitis occurred in Carabobo and Barinas States of western Venezuela. Virus isolates from horses in each location were nearly identical in sequence to 1995 isolates, which suggests natural persistence of subtype IC VEE virus (VEEV) strains in a genetically stable mode. Serologic evidence indicated that additional outbreaks occurred in Barinas State in 2003. Field studies identified known Culex (Melanoconion) spp. vectors and reservoir hosts of enzootic VEEV but a dearth of typical epidemic vectors. Cattle serosurveys indicated the recent circulation of enzootic VEEV strains, and possibly of epizootic strains. Persistence of VEEV subtype IC strains and infection of horses at the end of the rainy season suggest the possibility of an alternative, cryptic transmission cycle involving survival through the dry season of infected vectors or persistently infected vertebrates.
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Affiliation(s)
| | - Gladys Medina
- Instituto Nacional de Investigaciones Agropecuarias, Maracay, Venezuela
| | | | - Lark L. Coffey
- University of Texas Medical Branch, Galveston, Texas, USA
| | - Eryu Wang
- University of Texas Medical Branch, Galveston, Texas, USA
| | - Alexander Suárez
- Universidad Central de Venezuela, Caracas, Venezuela
- Instituto Nacional de Higiene, Caracas, Venezuela
| | - Hernán Biord
- Sociedad Venezolana de Ciencias Naturales, Venezuela
| | - Marlene Salas
- Ministerio de Agricultura y Tierras, Barinas, Venezuela
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Ortiz DI, Anishchenko M, Weaver SC. Susceptibility of Psorophora confinnis (Diptera: Culicidae) to infection with epizootic (subtype IC) and enzootic (subtype ID) Venezuelan Equine encephalitis viruses. JOURNAL OF MEDICAL ENTOMOLOGY 2005; 42:857-63. [PMID: 16365999 DOI: 10.1093/jmedent/42.5.857] [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: 05/05/2023]
Abstract
To test the hypothesis that adaptation to epizootic mosquito vectors mediates the emergence of Venezuelan equine encephalitis virus (family Togaviridae, genus Alphavirus, VEEV) from enzootic progenitors, the susceptibility of the epizootic vector Psorophora confinnis (Lynch-Arribalzaga) to epizootic versus enzootic strains was evaluated. Artificial bloodmeals containing subtype IC strains isolated during the 1962-1964, 1992-1993, and 1995 Venezuelan/Colombian epizootics and closely related Venezuelan enzootic subtype ID strains were used to compare mosquito infectivity and transmission potential. Strains from the smaller 1992-1993 epizootic showed lower or equal infectivity and replication compared with enzootic viruses and to strains isolated during the larger 1962-1964 and 1995 epizootics. These experiments failed to provide evidence that Ps. confinnis selects for epizootic VEEV viruses with higher infectivity, as has been shown for Aedes (Ochlerotatus) taeniorhynchus (Wiedemann). Nonetheless, its high susceptibility, abundance in enzootic and epizootic regions, and feeding behavior suggest that Ps. confinnis is an important bridge vector for both enzootic and epizootic VEEV.
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Affiliation(s)
- Diana I Ortiz
- Center for Biodefense and Emerging Infectious Diseases, Department of Pathology, University of Texas Medical Branch, Galveston, TX 77555-0609, USA
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Reed DS, Lind CM, Lackemeyer MG, Sullivan LJ, Pratt WD, Parker MD. Genetically engineered, live, attenuated vaccines protect nonhuman primates against aerosol challenge with a virulent IE strain of Venezuelan equine encephalitis virus. Vaccine 2005; 23:3139-47. [PMID: 15837213 DOI: 10.1016/j.vaccine.2004.12.023] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2004] [Revised: 12/22/2004] [Accepted: 12/23/2004] [Indexed: 10/25/2022]
Abstract
Two live, attenuated strains of Venezuelan equine encephalitis virus (VEE), IE1150K and V3526, were administered to macaques to determine if they could elicit protection against an aerosol challenge with virulent VEE virus of the IE variety (VEEV-IE). These viruses were rescued from full-length cDNA clones of 68U201 (VEEV-IE variety) and Trinidad donkey (VEEV-IA/B variety), respectively, and both have a furin cleavage site deletion mutation and a second-site resuscitating mutation. Both vaccines elicited neutralizing antibodies to viruses of the homologous variety but not to viruses of the heterologous variety. Eight weeks after vaccination, the macaques were challenged by aerosol exposure to virulent 68U201. Macaques vaccinated with V3526 were protected as well as macaques inoculated with IE1009, the wild-type infectious clone of 68U201. However, IE1150K failed to significantly protect macaques relative to controls. V3526 has now been shown to protect macaques against both IA/B [Pratt WD, Davis NL, Johnston RE, Smith JF. Genetically engineered, live attenuated vaccines for Venezuelan equine encephalitis: testing in animal models. Vaccine 2003;21(25-26):3854-62] and IE strains of VEE viruses.
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Affiliation(s)
- Douglas S Reed
- Center for Aerobiological Sciences, U.S. Army Medical Research Institute of Infectious Diseases, 1425 Porter Street, Fort Detrick, Frederick, MD 21702-5011, USA.
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Greene IP, Paessler S, Austgen L, Anishchenko M, Brault AC, Bowen RA, Weaver SC. Envelope glycoprotein mutations mediate equine amplification and virulence of epizootic venezuelan equine encephalitis virus. J Virol 2005; 79:9128-33. [PMID: 15994807 PMCID: PMC1168750 DOI: 10.1128/jvi.79.14.9128-9133.2005] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Epidemics of Venezuelan equine encephalitis (VEE) result from high-titer equine viremia of IAB and IC subtype viruses that mediate increased mosquito transmission and spillover to humans. Previous genetic studies suggest that mutations in the E2 envelope glycoprotein allow relatively viremia-incompetent, enzootic subtype ID strains to adapt for equine replication, leading to VEE emergence. To test this hypothesis directly, chimeric VEEV strains containing the genetic backbone of enzootic subtype ID strains and the partial envelope glycoprotein genes of epizootic subtype IC and IAB strains, as well as reciprocal chimeras, were used for experimental infections of horses. Insertion of envelope genes from two different, closely related enzootic subtype ID strains into the epizootic backbones resulted in attenuation, demonstrating that the epizootic envelope genes are necessary for the equine-virulent and viremia-competent phenotypes. The partial epizootic envelope genes introduced into an enzootic ID backbone were sufficient to generate the virulent, viremia-competent equine phenotype. These results indicate that a small number of envelope gene mutations can generate an equine amplification-competent, epizootic VEEV from an enzootic progenitor and underscore the limitations of small animal models for evaluating and predicting the epizootic phenotype.
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Affiliation(s)
- Ivorlyne P Greene
- Center for Biodefense and Emerging Infectious Diseases, University of Texas Medical Branch, Galveston, TX 77555-0609, USA
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Coffey LL, Carrara AS, Paessler S, Haynie ML, Bradley RD, Tesh RB, Weaver SC. Experimental Everglades virus infection of cotton rats (Sigmodon hispidus). Emerg Infect Dis 2005; 10:2182-8. [PMID: 15663857 PMCID: PMC3323382 DOI: 10.3201/eid1012.040442] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
We characterized Everglades virus infection of cotton rats from South Florida to validate their role as reservoir hosts in the enzootic transmission cycle. Everglades virus (EVEV), an alphavirus in the Venezuelan equine encephalitis (VEE) serocomplex, circulates among rodents and vector mosquitoes and infects humans, causing a febrile disease sometimes accompanied by neurologic manifestations. EVEV circulates near metropolitan Miami, which indicates the potential for substantial human disease, should outbreaks arise. We characterized EVEV infection of cotton rats in South Florida, USA, to validate their role in enzootic transmission. To evaluate whether the viremia induced in cotton rat populations regulates EVEV distribution, we also infected rats from a non–EVEV-endemic area. Viremia levels developed in rats from both localities that exceeded the threshold for infection of the vector. Most animals survived infection with no signs of illness, despite virus invasion of the brain and the development of mild encephalitis. Understanding the mechanisms by which EVEV-infected cotton rats resist clinical disease may be useful in developing VEE therapeutics for equines and humans.
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Affiliation(s)
- Lark L Coffey
- University of Texas Medical Branch, Galveston, Texas 77555-0609, USA
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Novella IS, Gilbertson DL, Borrego B, Domingo E, Holland JJ. Adaptability costs in immune escape variants of vesicular stomatitis virus. Virus Res 2005; 107:27-34. [PMID: 15567030 DOI: 10.1016/j.virusres.2004.06.007] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2004] [Revised: 06/16/2004] [Accepted: 06/16/2004] [Indexed: 10/26/2022]
Abstract
We have used vesicular stomatitis virus (VSV) to determine the cost of antiserum resistance during escape from a polyclonal immune response. Replication of VSV in the presence of polyclonal antiserum resulted in the selection of antibody-escape mutants, as shown by increased fitness in the presence of antiserum and by increased resistance to neutralization. However, resistance came at a cost of overall fitness loss in the BHK-21 host cells. Sequencing of the surface G glycoprotein showed that two to four mutations were fixed in each population, most of which mapped in the A1 and A2 antigenic sites. Selected resistant populations were passaged as large populations in BHK-21 cells under constant conditions, which would normally lead to fitness increases. Nevertheless, many of the populations showed little or no sign of recovery, although the resistant phenotype was maintained. These results suggest that while antiserum resistance can develop, it may come at a cost in fitness and further limitations in the adaptability of the populations.
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Affiliation(s)
- Isabel S Novella
- Department of Microbiology and Immunology, Medical College of Ohio, 3055 Arlington Avenue Toledo, OH 43614, USA.
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Ortiz DI, Weaver SC. Susceptibility of Ochlerotatus taeniorhynchus (Diptera: Culicidae) to infection with epizootic (subtype IC) and enzootic (subtype ID) Venezuelan equine encephalitis viruses: evidence for epizootic strain adaptation. JOURNAL OF MEDICAL ENTOMOLOGY 2004; 41:987-993. [PMID: 15535633 DOI: 10.1603/0022-2585-41.5.987] [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
To test the hypothesis that adaptation to epizootic mosquito vectors mediates emergence of Venezuelan equine encephalitis virus (VEEV) from enzootic progenitors, experimental infection studies were conducted to determine the susceptibility of Ochlerotatus taeniorhynchus (Wiedemann) to epizootic and enzootic strains. Artificial blood meals containing epizootic subtype IC strains isolated during the 1962-1964, 1992-1993, and 1995 Venezuelan/Colombian epizootics and closely related Venezuelan enzootic subtype ID strains were used to compare infectivity and transmission potential. Their greater infectivity and replication suggested that adaptation of epizootic strains to Oc. taeniorhynchus may have enhanced epizootic transmission during the 1962-1964 and 1995 IC coastal epizootics. However, strains from the small 1992-1993 Venezuelan outbreak that did not extend to coastal regions do not seem to infect this species better than closely related subtype ID strains. Adaptation of VEEV to epizootic vectors such as Oc. taeniorhynchus mosquitoes may be a determinant of some but not all VEE emergence events and may influence spread into coastal regions.
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Affiliation(s)
- Diana I Ortiz
- Center for Biodefense and Emerging Infectious Diseases and Department of Pathology, University of Texas Medical Branch, Galveston, TX 77555-0609, USA
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Aguilar PV, Greene IP, Coffey LL, Medina G, Moncayo AC, Anishchenko M, Ludwig GV, Turell MJ, O'Guinn ML, Lee J, Tesh RB, Watts DM, Russell KL, Hice C, Yanoviak S, Morrison AC, Klein TA, Dohm DJ, Guzman H, Travassos da Rosa APA, Guevara C, Kochel T, Olson J, Cabezas C, Weaver SC. Endemic Venezuelan equine encephalitis in northern Peru. Emerg Infect Dis 2004; 10:880-8. [PMID: 15200823 PMCID: PMC3323213 DOI: 10.3201/eid1005.030634] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Since Venezuelan equine encephalitis virus (VEEV) was isolated in Peru in 1942, >70 isolates have been obtained from mosquitoes, humans, and sylvatic mammals primarily in the Amazon region. To investigate genetic relationships among the Peru VEEV isolates and between the Peru isolates and other VEEV strains, a fragment of the PE2 gene was amplified and analyzed by single-stranded conformation polymorphism. Representatives of seven genotypes underwent sequencing and phylogenetic analysis. The results identified four VEE complex lineages that cocirculate in the Amazon region: subtypes ID (Panama and Colombia/Venezuela genotypes), IIIC, and a new, proposed subtype IIID, which was isolated from a febrile human, mosquitoes, and spiny rats. Both ID lineages and the IIID subtype are associated with febrile human illness. Most of the subtype ID isolates belonged to the Panama genotype, but the Colombia/Venezuela genotype, which is phylogenetically related to epizootic strains, also continues to circulate in the Amazon basin.
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Brault AC, Powers AM, Ortiz D, Estrada-Franco JG, Navarro-Lopez R, Weaver SC. Venezuelan equine encephalitis emergence: enhanced vector infection from a single amino acid substitution in the envelope glycoprotein. Proc Natl Acad Sci U S A 2004; 101:11344-9. [PMID: 15277679 PMCID: PMC509205 DOI: 10.1073/pnas.0402905101] [Citation(s) in RCA: 137] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
In 1993 and 1996, subtype IE Venezuelan equine encephalitis (VEE) virus caused epizootics in the Mexican states of Chiapas and Oaxaca. Previously, only subtype IAB and IC VEE virus strains had been associated with major outbreaks of equine and human disease. The IAB and IC epizootics are believed to emerge via adaptation of enzootic (sylvatic, equine-avirulent) strains for high titer equine viremia that results in efficient infection of mosquito vectors. However, experimental equine infections with subtype IE equine isolates from the Mexican outbreaks demonstrated neuro-virulence but little viremia, inconsistent with typical VEE emergence mechanisms. Therefore, we hypothesized that changes in the mosquito vector host range might have contributed to the Mexican emergence. To test this hypothesis, we evaluated the susceptibility of the most abundant mosquito in the deforested Pacific coastal locations of the VEE outbreaks and a proven epizootic vector, Ochlerotatus taeniorhynchus. The Mexican epizootic equine isolates exhibited significantly greater infectivity compared with closely related enzootic strains, supporting the hypothesis that adaptation to an efficient epizootic vector contributed to disease emergence. Reverse genetic studies implicated a Ser --> Asn substitution in the E2 envelope glycoprotein as the major determinant of the increased vector infectivity phenotype. Our findings underscore the capacity of RNA viruses to alter their vector host range through minor genetic changes, resulting in the potential for disease emergence.
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Affiliation(s)
- Aaron C Brault
- Center for Biodefense and Emerging Infectious Diseases and Department of Pathology, University of Texas Medical Branch, Galveston, TX 77555-0609, USA
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Weaver SC, Anishchenko M, Bowen R, Brault AC, Estrada-Franco JG, Fernandez Z, Greene I, Ortiz D, Paessler S, Powers AM. Genetic determinants of Venezuelan equine encephalitis emergence. ARCHIVES OF VIROLOGY. SUPPLEMENTUM 2004:43-64. [PMID: 15119762 DOI: 10.1007/978-3-7091-0572-6_5] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/29/2023]
Abstract
Following a period of inactivity from 1973-1991, Venezuelan equine encephalitis (VEE) reemerged during the past decade in South America and Mexico. Experimental studies of VEE virus (VEEV) infection of horses with virus strains isolated during these outbreaks have revealed considerable variation in the ability of equine-virulent, epizootic strains to exploit horses as efficient amplification hosts. Subtype IC strains from recent outbreaks in Venezuela and Colombia amplify efficiently in equines, with a correlation between maximum viremia titers and the extent of the outbreak from which the virus strain was isolated. Studies of enzootic VEEV strains that are believed to represent progenitors of the epizootic subtypes support the hypothesis that adaptation to efficient replication in equines is a major determinant of emergence and the ability of VEEV to spread geographically. Correlations between the ability of enzootic and epizootic VEEV strains to infect abundant, equiphilic mosquitoes, and the location and extent of these outbreaks, also suggest that specific adaptation to Ochlerotatus taeniorhynchus mosquitoes is a determinant of some but not all emergence events. Genetic studies imply that mutations in the E2 envelope glycoprotein gene are major determinants of adaptation to both equines and mosquito vectors.
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Affiliation(s)
- S C Weaver
- Center for Biodefense and Emerging Infectious Diseases and Department of Pathology, University of Texas Medical Branch, Galveston, Texas 77555-0609, USA.
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Anishchenko M, Paessler S, Greene IP, Aguilar PV, Carrara AS, Weaver SC. Generation and characterization of closely related epizootic and enzootic infectious cDNA clones for studying interferon sensitivity and emergence mechanisms of Venezuelan equine encephalitis virus. J Virol 2004; 78:1-8. [PMID: 14671082 PMCID: PMC303380 DOI: 10.1128/jvi.78.1.1-8.2004] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Venezuelan equine encephalitis virus (VEEV) is a reemerging pathogen and a continuing threat to humans and equines in the Americas. Identification of the genetic determinants that enable epizootic VEEV strains to arise and exploit equines as amplification hosts to cause widespread human disease is pivotal to understanding VEE emergence. The sensitivity to murine alpha/beta interferon-mediated antiviral activity was previously correlated to the epizootic phenotype of several VEEV strains. Infectious cDNA clones were generated from an epizootic subtype IC VEEV strain (SH3) isolated during the 1992 Venezuelan outbreak and a closely related enzootic, sympatric subtype ID strain (ZPC738). These VEEV strains had low-cell-culture-passage histories and differed by only 12 amino acids in the nonstructural and structural proteins. Rescued viruses showed similar growth kinetics to their parent viruses in several cell lines, and murine infections resulted in comparable viremia and disease. Unlike what was found in other studies of epizootic and enzootic VEEV strains, the sensitivities to murine alpha/beta interferon did not differ appreciably between these epizootic versus enzootic strains, calling into question the reliability of interferon sensitivity as a marker of epizootic potential.
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Affiliation(s)
- Michael Anishchenko
- Center for Biodefense and Emerging Infectious Diseases, University of Texas Medical Branch, Galveston, Texas 77555-0609, USA
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Griffin DE, Byrnes AP, Cook SH. Emergence and virulence of encephalitogenic arboviruses. ARCHIVES OF VIROLOGY. SUPPLEMENTUM 2004:21-33. [PMID: 15119760 DOI: 10.1007/978-3-7091-0572-6_3] [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: 04/29/2023]
Abstract
Each arbovirus that causes encephalitis is geographically restricted by the availability of appropriate vectors and reservoir hosts. These viruses evolve regionally by recombination, reassortment and point mutation and can "emerge" as causes of human encephalitis through extension to new geographic regions or by selection of more virulent or more efficiently transmitted virus variants. The properties of arboviruses that result in encephalitis involve efficient replication in peripheral tissues after initiation of infection, production of a viremia, entry into the central nervous system and efficient replication in neurons with spread to additional populations of neurons. Many of these steps are determined by properties of the envelope glycoproteins responsible for cellular attachment, but changes in noncoding regions of the genome, as well as in other structural and nonstructural proteins, also contribute to neurovirulence.
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Affiliation(s)
- D E Griffin
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland 21205, USA.
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