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Swetnam DM, Stuart JB, Young K, Maharaj PD, Fang Y, Garcia S, Barker CM, Smith K, Godsey MS, Savage HM, Barton V, Bolling BG, Duggal N, Brault AC, Coffey LL. Movement of St. Louis encephalitis virus in the Western United States, 2014- 2018. PLoS Negl Trop Dis 2020; 14:e0008343. [PMID: 32520944 PMCID: PMC7307790 DOI: 10.1371/journal.pntd.0008343] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2019] [Revised: 06/22/2020] [Accepted: 05/02/2020] [Indexed: 11/22/2022] Open
Abstract
St. Louis encephalitis virus (SLEV) is a flavivirus that circulates in an enzootic cycle between birds and mosquitoes and can also infect humans to cause febrile disease and sometimes encephalitis. Although SLEV is endemic to the United States, no activity was detected in California during the years 2004 through 2014, despite continuous surveillance in mosquitoes and sentinel chickens. In 2015, SLEV-positive mosquito pools were detected in Maricopa County, Arizona, concurrent with an outbreak of human SLEV disease. SLEV-positive mosquito pools were also detected in southeastern California and Nevada in summer 2015. From 2016 to 2018, SLEV was detected in mosquito pools throughout southern and central California, Oregon, Idaho, and Texas. To understand genetic relatedness and geographic dispersal of SLEV in the western United States since 2015, we sequenced four historical genomes (3 from California and 1 from Louisiana) and 26 contemporary SLEV genomes from mosquito pools from locations across the western US. Bayesian phylogeographic approaches were then applied to map the recent spread of SLEV. Three routes of SLEV dispersal in the western United States were identified: Arizona to southern California, Arizona to Central California, and Arizona to all locations east of the Sierra Nevada mountains. Given the topography of the Western United States, these routes may have been limited by mountain ranges that influence the movement of avian reservoirs and mosquito vectors, which probably represents the primary mechanism of SLEV dispersal. Our analysis detected repeated SLEV introductions from Arizona into southern California and limited evidence of year-to-year persistence of genomes of the same ancestry. By contrast, genetic tracing suggests that all SLEV activity since 2015 in central California is the result of a single persistent SLEV introduction. The identification of natural barriers that influence SLEV dispersal enhances our understanding of arbovirus ecology in the western United States and may also support regional public health agencies in implementing more targeted vector mitigation efforts to protect their communities more effectively. Following the detection of West Nile virus in the United States, evidence of the historically endemic and closely related virus, St. Louis encephalitis virus (SLEV), dropped nationwide. However, in 2015, a novel genotype of SLEV, previously restricted to Argentina, was identified as the etiological agent of an outbreak of neurological disease in Arizona, United States. Since that time, the genotype has expanded throughout the Western United States, including into California, Nevada, Texas, Idaho, and Oregon. In this study, samples containing SLEV, provided by public health and mosquito abatement agencies, were sequenced and used in phylogenetic analyses to infer patterns of SLEV movement. Three independent routes of SLEV dispersal were identified: Arizona to Southern California, Arizona to Central California, and Arizona to all locations east of the Sierra Nevada mountains. The Sierra Nevada mountains and the Transverse Ranges appear to separate the three routes of SLEV movement, suggesting that geographic features may act as barriers to virus dispersal. Identification of patterns of SLEV dispersal can support regional public health agencies in improving vector mitigation efforts to protect their communities more effectively.
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Affiliation(s)
- Daniele M. Swetnam
- Department of Pathology, Microbiology, and Immunology, School of Veterinary Medicine, University of California, Davis, Davis, California, United States of America
| | - Jackson B. Stuart
- Department of Pathology, Microbiology, and Immunology, School of Veterinary Medicine, University of California, Davis, Davis, California, United States of America
| | - Katherine Young
- Department of Pathology, Microbiology, and Immunology, School of Veterinary Medicine, University of California, Davis, Davis, California, United States of America
| | - Payal D. Maharaj
- Division of Vector-borne Diseases, Centers for Disease Control, Fort Collins, Colorado, United States of America
| | - Ying Fang
- Department of Pathology, Microbiology, and Immunology, School of Veterinary Medicine, University of California, Davis, Davis, California, United States of America
| | - Sandra Garcia
- Department of Pathology, Microbiology, and Immunology, School of Veterinary Medicine, University of California, Davis, Davis, California, United States of America
| | - Christopher M. Barker
- Department of Pathology, Microbiology, and Immunology, School of Veterinary Medicine, University of California, Davis, Davis, California, United States of America
| | - Kirk Smith
- Maricopa County Environmental Services Department, Phoenix, Arizona, United States of America
| | - Marvin S. Godsey
- Division of Vector-borne Diseases, Centers for Disease Control, Fort Collins, Colorado, United States of America
| | - Harry M. Savage
- Division of Vector-borne Diseases, Centers for Disease Control, Fort Collins, Colorado, United States of America
| | - Vonnita Barton
- Idaho Bureau of Laboratories, Boise, Idaho, United States of America
| | - Bethany G. Bolling
- Laboratory Services Section, Texas Department of State Health Services, Austin, Texas, United States of America
| | - Nisha Duggal
- Department of Molecular Biology, College of Veterinary Medicine, Virginia Polytechnic Institute and State University, Blacksburg, Virginia, United States of America
| | - Aaron C. Brault
- Division of Vector-borne Diseases, Centers for Disease Control, Fort Collins, Colorado, United States of America
| | - Lark L. Coffey
- Department of Pathology, Microbiology, and Immunology, School of Veterinary Medicine, University of California, Davis, Davis, California, United States of America
- * E-mail:
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Pacca CC, Marques RE, Espindola JWP, Filho GBOO, Leite ACL, Teixeira MM, Nogueira ML. Thiosemicarbazones and Phthalyl-Thiazoles compounds exert antiviral activity against yellow fever virus and Saint Louis encephalitis virus. Biomed Pharmacother 2017; 87:381-387. [PMID: 28068627 DOI: 10.1016/j.biopha.2016.12.112] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2016] [Revised: 12/23/2016] [Accepted: 12/26/2016] [Indexed: 11/24/2022] Open
Abstract
Arboviruses, arthropod-borneviruses, are frequency associated to human outbreak and represent a serious health problem. The genus Flavivirus, such as Yellow Fever Virus (YFV) and Saint Louis Encephalitis Virus (SLEV), are important pathogens with high morbidity and mortality worldwide. In Brazil, YFV is maintained in sylvatic cycle, but many cases are notified annually, despite the efficiency of vaccine. SLEV causes an acute encephalitis and is widely distributed in the Americas. There is no specific antiviral drugs for these viruses, only supporting treatment that can alleviate symptoms and prevent complications. Here, we evaluated the potential anti-YFV and SLEV activity of a series of thiosemicarbazones and phthalyl-thiazoles. Plaque reduction assay, flow cytometry, immunofluorescence and cellular viability were used to test the compounds in vitro. Treated cells showed efficient inhibition of the viral replication at concentrations that presented minimal toxicity to cells. The assays showed that phthalyl-thiazole and phenoxymethyl-thiosemicarbazone reduced 60% of YFV replication and 75% of SLEV replication.
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Affiliation(s)
- Carolina Colombelli Pacca
- Laboratório de Pesquisas em Virologia, Departamento de Doenças Dermatológicas, Infecciosas e Parasitarias, Faculdade de Medicina de São José do Rio Preto - FAMERP, 15090-000, São José do Rio Preto, SP, Brazil; Faceres Medical School, 15090-305, São José do Rio Preto, SP, Brazil
| | - Rafael Elias Marques
- Laboratório de Imunofarmacologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, 31270-901, Belo Horizonte, MG, Brazil
| | - José Wanderlan P Espindola
- Departamento de Ciências Farmacêuticas, Centro de Ciências da Saúde, Universidade Federal de Pernambuco, 50740-521, Recife, PE, Brazil
| | - Gevânio B O Oliveira Filho
- Departamento de Ciências Farmacêuticas, Centro de Ciências da Saúde, Universidade Federal de Pernambuco, 50740-521, Recife, PE, Brazil
| | - Ana Cristina Lima Leite
- Departamento de Ciências Farmacêuticas, Centro de Ciências da Saúde, Universidade Federal de Pernambuco, 50740-521, Recife, PE, Brazil
| | - Mauro Martins Teixeira
- Laboratório de Imunofarmacologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, 31270-901, Belo Horizonte, MG, Brazil
| | - Mauricio L Nogueira
- Laboratório de Pesquisas em Virologia, Departamento de Doenças Dermatológicas, Infecciosas e Parasitarias, Faculdade de Medicina de São José do Rio Preto - FAMERP, 15090-000, São José do Rio Preto, SP, Brazil.
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Ortiz A, Capitan Z, Mendoza Y, Cisneros J, Moreno B, Zaldivar Y, Garcia M, Smith RE, Motta J, Pascale JM. Simple, specific molecular typing of dengue virus isolates using one-step RT-PCR and restriction fragment length polymorphism. J Virol Methods 2012; 185:129-35. [PMID: 22766181 DOI: 10.1016/j.jviromet.2012.06.016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2011] [Revised: 06/03/2012] [Accepted: 06/12/2012] [Indexed: 11/26/2022]
Abstract
A one-step RT-PCR and one-enzyme RFLP was used to detect and distinguish among flaviviruses, including the four serotypes of dengue and the St. Louis Encephalitis, West Nile and Yellow Fever viruses in cultured virus samples or acute-phase human serum. Using a previously described RT-PCR, but novel RFLP procedure, results are obtained in 24 h with basic PCR and electrophoresis equipment. There is 95% agreement between RT-PCR/RFLP results and those achieved by indirect immunofluorescence assays, and 100% agreement between RT-PCR/RFLP results and gene sequencing. This method is more rapid than tests of cytopathic effect based on virus isolation in tissue culture, and simpler than real-time PCR. It does not require specialized equipment, radioisotopes or computer analysis and is a method that can be applied widely in the developing world. It allows for prompt determination of whether a flavivirus is the cause of illness in a febrile patient, rapid identification of dengue serotypes in circulation, and improved patient management in cases where prior dengue exposure make dengue hemorrhagic fever or dengue shock syndrome a risk.
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Affiliation(s)
- Alma Ortiz
- Gorgas Memorial Institute for Health Studies, Panama City, Panama.
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Day JF. Predicting St. Louis encephalitis virus epidemics: lessons from recent, and not so recent, outbreaks. ANNUAL REVIEW OF ENTOMOLOGY 2001; 46:111-138. [PMID: 11112165 DOI: 10.1146/annurev.ento.46.1.111] [Citation(s) in RCA: 91] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
St. Louis encephalitis virus was first identified as the cause of human disease in North America after a large urban epidemic in St. Louis, Missouri, during the summer of 1933. Since then, numerous outbreaks of St. Louis encephalitis have occurred throughout the continent. In south Florida, a 1990 epidemic lasted from August 1990 through January 1991 and resulted in 226 clinical cases and 11 deaths in 28 counties. This epidemic severely disrupted normal activities throughout the southern half of the state for 5 months and adversely impacted tourism in the affected region. The accurate forecasting of mosquito-borne arboviral epidemics will help minimize their impact on urban and rural population centers. Epidemic predictability would help focus control efforts and public education about epidemic risks, transmission patterns, and elements of personal protection that reduce the probability of arboviral infection. Research associated with arboviral outbreaks has provided an understanding of the strengths and weaknesses associated with epidemic prediction. The purpose of this paper is to review lessons from past arboviral epidemics and determine how these observations might aid our ability to predict and respond to future outbreaks.
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Affiliation(s)
- J F Day
- Florida Medical Entomology Laboratory, Institute of Food and Agricultural Sciences, University of Florida, Vero Beach, Florida 32962, USA.
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Stoll SW, Chia NV, Nair RP, Woods TL, Stuart P, Henseler T, Jenisch S, Christophers E, Voorhees JJ, Elder JT. S100A2 coding sequence polymorphism: characterization and lack of association with psoriasis. Clin Exp Dermatol 2001; 26:79-83. [PMID: 11260185 DOI: 10.1046/j.1365-2230.2001.00766.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Psoriasis is a chronic inflammatory skin disease with a strong genetic component. Linkage studies have identified several susceptibility loci for psoriasis including a region on chromosome 1q21 termed the 'epidermal differentiation complex'. At least 20 genes involved in epidermal differentiation and proliferation have been mapped to this region including S100A2, a gene known to be over-expressed in psoriasis lesions. In the course of cloning and sequencing several S100A2 cDNAs, we identified an A/G (Asn62Ser) polymorphism at nucleotide 185 of the S100A2 coding region. To determine whether this polymorphism is associated with psoriasis, we tested DNA from 38 unrelated normal and 40 unrelated psoriatic individuals. The 185G allele was present in 148 of the 156 chromosomes analysed, giving an allele frequency of 94.9%. All of the remaining chromosomes carried 185A. There was no significant difference in the allele distribution between normal and psoriatic individuals (normals 72G, 4A; psoriatics 76G, 4A; P = 1.00 by Fisher's exact test). Our data explain conflicting results in the literature regarding the sequence of S100A2 but provide no support for a direct causal role for S100A2 in psoriasis.
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Affiliation(s)
- S W Stoll
- The Department of The Department of Dermatology, University of Michigan Medical School, MI, USA
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