1
|
Rucci KA, Arias-Builes DL, Visintin AM, Diaz A. Serological survey reveals enzootic circulation of St. Louis encephalitis and West Nile viruses in semiarid Monte ecosystem of Argentina. Sci Rep 2024; 14:4994. [PMID: 38424362 PMCID: PMC10904362 DOI: 10.1038/s41598-024-55723-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2023] [Accepted: 02/27/2024] [Indexed: 03/02/2024] Open
Abstract
St. Louis encephalitis virus (SLEV) and West Nile virus (WNV) are arboviruses transmitted by Culex mosquitoes and amplified in avian hosts. The present study aimed to investigate the presence and seasonal circulation of SLEV and WNV in La Rioja province, within the semiarid ecoregion of the Monte, Argentina. Over a two-year period, avian sera were collected and tested for neutralizing antibodies against SLEV and WNV. Our results reveal the enzootic activity of both viruses in this challenging environment. SLEV seroprevalence was 4.5% (35/778), with higher activity in spring (2016) and autumn (2017). WNV seroprevalence was 3.5% (27/778), peaking during the summer 2016-2017. Greater seroprevalence for SLEV in 2016 was detected for the Lark-like Brushrunner (Coryphistera alaudina) and the Short-billed Canastero (Asthenes baeri) and in 2017 for the Black-crested Finch (Lophospingus pusillus) and Lark-like Brushrunner, whereas for WNV greater seroprevalence in 2016 was detected for the Picui Ground Dove (Columbina picui) and in 2017 for the Lark-like Brushrunner and Band-tailed Seedeater (Catamenia analis). Additionally, five avian individuals experienced seroconversion during the sampling period, namely the Lark-like Brushrunner and White-fronted Woodpecker (Melanerpes cactorum) for SLEV, and the Lark-like Brushrunner, Greater Wagtail Tyrant (Stigmatura budytoides) and Many-colored Chaco Finch (Saltatricula multicolor) for WNV. The study highlights the persistence and circulation of these viruses in a semiarid ecosystem, raising questions about overwintering mechanisms and transmission dynamics. This research contributes to understanding arbovirus ecology in diverse environments. Further investigations are needed to assess the specific mechanisms facilitating virus persistence in the Monte ecoregion.
Collapse
Affiliation(s)
- Kevin A Rucci
- Laboratorio de Arbovirus, Instituto de Virología "Dr. J. M. Vanella", Facultad de Ciencias Médicas, Universidad Nacional de Córdoba, Córdoba, Argentina
- Ministerio de Ciencia, Tecnología e Innovación, Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Ciudad Autónoma de Buenos Aires, Argentina
| | - Diego L Arias-Builes
- Departamento de Ciencias Básicas y Tecnológicas, Universidad Nacional de Chilecito, Chilecito, La Rioja, Argentina
| | - Andrés M Visintin
- Ministerio de Ciencia, Tecnología e Innovación, Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Ciudad Autónoma de Buenos Aires, Argentina
- Centro de Investigación e Innovación Tecnológica (CENIIT), Instituto de Biología de la Conservación y Paleobiología (IBICOPA), Universidad Nacional de La Rioja, La Rioja, Argentina
- Centro de Investigaciones Entomológicas de Córdoba, Instituto de Investigaciones Biológicas y Tecnológicas (IIByT), Facultad de Ciencias Exactas, Físicas y Naturales, Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Adrián Diaz
- Laboratorio de Arbovirus, Instituto de Virología "Dr. J. M. Vanella", Facultad de Ciencias Médicas, Universidad Nacional de Córdoba, Córdoba, Argentina.
- Ministerio de Ciencia, Tecnología e Innovación, Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Ciudad Autónoma de Buenos Aires, Argentina.
| |
Collapse
|
2
|
Sotorilli GE, Gravina HD, de Carvalho AC, Shimizu JF, Fontoura MA, Melo-Hanchuk TD, Cordeiro AT, Marques RE. Phenotypical Screening of an MMV Open Box Library and Identification of Compounds with Antiviral Activity against St. Louis Encephalitis Virus. Viruses 2023; 15:2416. [PMID: 38140657 PMCID: PMC10747599 DOI: 10.3390/v15122416] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2023] [Revised: 12/02/2023] [Accepted: 12/09/2023] [Indexed: 12/24/2023] Open
Abstract
St. Louis encephalitis virus (SLEV) is a neglected mosquito-borne Flavivirus that may cause severe neurological disease in humans and other animals. There are no specific treatments against SLEV infection or disease approved for human use, and drug repurposing may represent an opportunity to accelerate the development of treatments against SLEV. Here we present a scalable, medium-throughput phenotypic cell culture-based screening assay on Vero CCL81 cells to identify bioactive compounds that could be repurposed against SLEV infection. We screened eighty compounds from the Medicines for Malaria Venture (MMV) COVID Box library to identify nine (11%) compounds that protected cell cultures from SLEV-induced cytopathic effects, with low- to mid-micromolar potencies. We validated six hit compounds using viral plaque-forming assays to find that the compounds ABT-239, Amiodarone, Fluphenazine, Posaconazole, Triparanol, and Vidofludimus presented varied levels of antiviral activity and selectivity depending on the mammalian cell type used for testing. Importantly, we identified and validated the antiviral activity of the anti-flavivirus nucleoside analog 7DMA against SLEV. Triparanol and Fluphenazine reduced infectious viral loads in both Vero CCL81 and HBEC-5i cell cultures and, similar to the other validated compounds, are likely to exert antiviral activity through a molecular target in the host.
Collapse
Affiliation(s)
- Giuliana Eboli Sotorilli
- Brazilian Biosciences National Laboratory (LNBio), Brazilian Center for Research in Energy and Materials (CNPEM), Campinas 13083-100, Brazil; (G.E.S.); (H.D.G.); (A.C.d.C.); (J.F.S.); (M.A.F.); (T.D.M.-H.); (A.T.C.)
- Department of Genetics, Microbiology and Immunology, Institute of Biology, State University of Campinas (UNICAMP), Campinas 13083-100, Brazil
| | - Humberto Doriguetto Gravina
- Brazilian Biosciences National Laboratory (LNBio), Brazilian Center for Research in Energy and Materials (CNPEM), Campinas 13083-100, Brazil; (G.E.S.); (H.D.G.); (A.C.d.C.); (J.F.S.); (M.A.F.); (T.D.M.-H.); (A.T.C.)
| | - Ana Carolina de Carvalho
- Brazilian Biosciences National Laboratory (LNBio), Brazilian Center for Research in Energy and Materials (CNPEM), Campinas 13083-100, Brazil; (G.E.S.); (H.D.G.); (A.C.d.C.); (J.F.S.); (M.A.F.); (T.D.M.-H.); (A.T.C.)
- Department of Genetics, Microbiology and Immunology, Institute of Biology, State University of Campinas (UNICAMP), Campinas 13083-100, Brazil
| | - Jacqueline Farinha Shimizu
- Brazilian Biosciences National Laboratory (LNBio), Brazilian Center for Research in Energy and Materials (CNPEM), Campinas 13083-100, Brazil; (G.E.S.); (H.D.G.); (A.C.d.C.); (J.F.S.); (M.A.F.); (T.D.M.-H.); (A.T.C.)
| | - Marina Alves Fontoura
- Brazilian Biosciences National Laboratory (LNBio), Brazilian Center for Research in Energy and Materials (CNPEM), Campinas 13083-100, Brazil; (G.E.S.); (H.D.G.); (A.C.d.C.); (J.F.S.); (M.A.F.); (T.D.M.-H.); (A.T.C.)
- Department of Cellular and Structural Biology, Institute of Biology, State University of Campinas (UNICAMP), Campinas 13083-100, Brazil
| | - Talita Diniz Melo-Hanchuk
- Brazilian Biosciences National Laboratory (LNBio), Brazilian Center for Research in Energy and Materials (CNPEM), Campinas 13083-100, Brazil; (G.E.S.); (H.D.G.); (A.C.d.C.); (J.F.S.); (M.A.F.); (T.D.M.-H.); (A.T.C.)
| | - Artur Torres Cordeiro
- Brazilian Biosciences National Laboratory (LNBio), Brazilian Center for Research in Energy and Materials (CNPEM), Campinas 13083-100, Brazil; (G.E.S.); (H.D.G.); (A.C.d.C.); (J.F.S.); (M.A.F.); (T.D.M.-H.); (A.T.C.)
| | - Rafael Elias Marques
- Brazilian Biosciences National Laboratory (LNBio), Brazilian Center for Research in Energy and Materials (CNPEM), Campinas 13083-100, Brazil; (G.E.S.); (H.D.G.); (A.C.d.C.); (J.F.S.); (M.A.F.); (T.D.M.-H.); (A.T.C.)
| |
Collapse
|
3
|
Cardozo F, Bernal C, Rojas A, Diaz A, Spinsanti L, Páez M, Guillén Y, Lesterhuis A, Yanosky A, Contigiani M, Mendoza L. Detection of neutralizing antibodies against flaviviruses in free-ranging birds, Paraguay (2016-2018). Trans R Soc Trop Med Hyg 2023; 117:61-63. [PMID: 35927790 DOI: 10.1093/trstmh/trac067] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2022] [Revised: 06/07/2022] [Accepted: 08/01/2022] [Indexed: 01/05/2023] Open
Abstract
Saint Louis encephalitis virus (SLEV), West Nile virus (WNV) and Ilheus virus (ILHV) are flaviviruses maintained by enzootic transmission networks between mosquitoes and birds. They have been detected in South America, with no records for Paraguay. We detected the presence of neutralizing antibodies for SLEV, WNV and ILHV in free-ranging birds collected in Paraguay (2016-2018). Four positive samples were detected in resident birds: one SLEV (rufous-bellied thrush), one WNV (barred antshrike) and two ILHV (white-tipped dove and shiny cowbird). These results bring new information about enzootic activity of flaviviruses in Paraguay.
Collapse
Affiliation(s)
- Fátima Cardozo
- Instituto de Investigaciones en Ciencias de la Salud, Universidad Nacional de Asunción, San Lorenzo, Paraguay
| | - Cynthia Bernal
- Instituto de Investigaciones en Ciencias de la Salud, Universidad Nacional de Asunción, San Lorenzo, Paraguay
| | - Alejandra Rojas
- Instituto de Investigaciones en Ciencias de la Salud, Universidad Nacional de Asunción, San Lorenzo, Paraguay
| | - Adrián Diaz
- Instituto de Virología, "Dr J.M. Vanella", Facultad de Ciencias Médicas, Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Lorena Spinsanti
- Instituto de Virología, "Dr J.M. Vanella", Facultad de Ciencias Médicas, Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Malvina Páez
- Instituto de Investigaciones en Ciencias de la Salud, Universidad Nacional de Asunción, San Lorenzo, Paraguay
| | - Yvalena Guillén
- Instituto de Investigaciones en Ciencias de la Salud, Universidad Nacional de Asunción, San Lorenzo, Paraguay
| | | | - Alberto Yanosky
- Estructura Interdisciplinaria de Investigación Integral Socio-Ambiental, Universidad Autónoma de Encarnación, Encarnación, Paraguay
| | - Marta Contigiani
- Instituto de Virología, "Dr J.M. Vanella", Facultad de Ciencias Médicas, Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Laura Mendoza
- Instituto de Investigaciones en Ciencias de la Salud, Universidad Nacional de Asunción, San Lorenzo, Paraguay
| |
Collapse
|
4
|
Danforth ME, Snyder RE, Feiszli T, Bullick T, Messenger S, Hanson C, Padgett K, Coffey LL, Barker CM, Reisen WK, Kramer VL. Epidemiologic and environmental characterization of the Re-emergence of St. Louis Encephalitis Virus in California, 2015-2020. PLoS Negl Trop Dis 2022; 16:e0010664. [PMID: 35939506 PMCID: PMC9387929 DOI: 10.1371/journal.pntd.0010664] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2022] [Revised: 08/18/2022] [Accepted: 07/15/2022] [Indexed: 11/18/2022] Open
Abstract
St. Louis encephalitis virus (SLEV) is an endemic flavivirus in the western and southeastern United States, including California. From 1938 to 2003, the virus was detected annually in California, but after West Nile virus (WNV) arrived in 2003, SLEV was not detected again until it re-emerged in Riverside County in 2015. The re-emerging virus in California and other areas of the western US is SLEV genotype III, which previously had been detected only in Argentina, suggesting a South American origin. This study describes SLEV activity in California since its re-emergence in 2015 and compares it to WNV activity during the same period. From 2015 to 2020, SLEV was detected in 1,650 mosquito pools and 26 sentinel chickens, whereas WNV was detected concurrently in 18,108 mosquito pools and 1,542 sentinel chickens from the same samples. There were 24 reported human infections of SLEV in 10 California counties, including two fatalities (case fatality rate: 8%), compared to 2,469 reported human infections of WNV from 43 California counties, with 143 fatalities (case fatality rate: 6%). From 2015 through 2020, SLEV was detected in 17 (29%) of California's 58 counties, while WNV was detected in 54 (93%). Although mosquitoes and sentinel chickens have been tested routinely for arboviruses in California for over fifty years, surveillance has not been uniform throughout the state. Of note, since 2005 there has been a steady decline in the use of sentinel chickens among vector control agencies, potentially contributing to gaps in SLEV surveillance. The incidence of SLEV disease in California may have been underestimated because human surveillance for SLEV relied on an environmental detection to trigger SLEV patient screening and mosquito surveillance effort is spatially variable. In addition, human diagnostic testing usually relies on changes in host antibodies and SLEV infection can be indistinguishable from infection with other flaviviruses such as WNV, which is more prevalent.
Collapse
Affiliation(s)
- Mary E. Danforth
- California Department of Public Health, Vector-Borne Disease Section, Richmond and Sacramento, California
| | - Robert E. Snyder
- California Department of Public Health, Vector-Borne Disease Section, Richmond and Sacramento, California
| | - Tina Feiszli
- California Department of Public Health, Vector-Borne Disease Section, Richmond and Sacramento, California
| | - Teal Bullick
- California Department of Public Health, Viral and Rickettsial Disease Laboratory, Richmond, California
| | - Sharon Messenger
- California Department of Public Health, Viral and Rickettsial Disease Laboratory, Richmond, California
| | - Carl Hanson
- California Department of Public Health, Viral and Rickettsial Disease Laboratory, Richmond, California
| | - Kerry Padgett
- California Department of Public Health, Vector-Borne Disease Section, Richmond and Sacramento, California
| | - Lark L. Coffey
- Department of Pathology, Microbiology and Immunology, School of Veterinary Medicine, University of California, Davis, California, United States of America
| | - Christopher M. Barker
- Department of Pathology, Microbiology and Immunology, School of Veterinary Medicine, University of California, Davis, California, United States of America
| | - William K. Reisen
- Department of Pathology, Microbiology and Immunology, School of Veterinary Medicine, University of California, Davis, California, United States of America
| | - Vicki L. Kramer
- California Department of Public Health, Vector-Borne Disease Section, Richmond and Sacramento, California
| |
Collapse
|
5
|
Mansilla AP, Grande JM, Diaz A. Effect of Agroecosystems on Seroprevalence of St. Louis Encephalitis and West Nile Viruses in Birds, La Pampa, Argentina, 2017-2019. Emerg Infect Dis 2022; 28:1393-1402. [PMID: 35731160 PMCID: PMC9239869 DOI: 10.3201/eid2807.211485] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
In Argentina, the Pampa ecoregion has been almost completely transformed into agroecosystems. To evaluate the environmental (agricultural area, tree coverage, distance to the nearest water body and urban site) and biological (dove, cowbird, and sparrow abundance) effects on free-ranging bird exposure to St. Louis encephalitis virus (SLEV) and West Nile virus (WNV), we used generalized linear mixed models. For 1,019 birds sampled during 2017–2019, neutralizing antibodies were found against SLEV in samples from 60 (5.8%) birds and against WNV for 21 (2.1%). The best variable for explaining SLEV seroprevalence was agricultural area, which had a positive effect; however, for WNV, no model was conclusive. Our results suggest that agroecosystems in the La Pampa ecoregion increase the exposure of avian hosts to SLEV, thus potentially increasing virus activity.
Collapse
|
6
|
Beeman SP, Downs JA, Unnasch TR, Unnasch RS. West Nile Virus and Eastern Equine Encephalitis Virus High Probability Habitat Identification for the Selection of Sentinel Chicken Surveillance Sites in Florida. J Am Mosq Control Assoc 2022; 38:1-6. [PMID: 35276726 DOI: 10.2987/21-7049] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
To mitigate the effects of West Nile virus (WNV) and eastern equine encephalitis virus (EEEV), the state of Florida conducts a serosurveillance program that uses sentinel chickens operated by mosquito control programs at numerous locations throughout the state. Coop locations were initially established to detect St. Louis encephalitis virus (SLEV), and coop placement was determined based on the location of human SLEV infections that occurred between 1959 and 1977. Since the introduction of WNV into Florida in 2001, WNV has surpassed SLEV as the primary arbovirus in Florida. Identifying high probability locations for WNV and EEEV transmission and relocating coops to areas of higher arbovirus activity would improve the sensitivity of the sentinel chicken surveillance program. Using 2 existing models, this study conducted an overlay analysis to identify areas with high probability habitats for both WNV and EEEV activity. This analysis identified approximately 7,800 km2 (about 4.5% of the state) as high probability habitat for supporting both WNV and EEEV transmission. Mosquito control programs can use the map resulting from this analysis to improve their sentinel chicken surveillance programs, increase the probability of virus detection, reduce operational costs, and allow for a faster, targeted response to virus detection.
Collapse
|
7
|
Zhang R, Tan P, Feng L, Li R, Yang J, Zhang R, Li J. External quality assessment of molecular testing of 9 viral encephalitis-related viruses in China. Virus Res 2021; 306:198598. [PMID: 34653568 DOI: 10.1016/j.virusres.2021.198598] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2021] [Revised: 10/04/2021] [Accepted: 10/05/2021] [Indexed: 11/17/2022]
Abstract
BACKGROUND Eastern equine encephalitis virus (EEEV), Western equine encephalitis virus (WEEV), Venezuelan equine encephalitis virus (VEEV), Hendra virus (HeV), Nipah virus (NiV), Yellow fever virus (YFV), West Nile virus (WNV), Saint Louis encephalitis virus (SLEV) and Tick-borne encephalitis virus (TBEV) have been detected in travelers returning to China and potentially pose a serious threat to public health. Real-time reverse transcription polymerase chain reaction (rRT-PCR) plays an important role in the detection of these viruses. Although these viruses are not mainly prevalent in China, occasionally imported cases have been reported with the increase in population mobility and entry-exit activities. Therefore, it is necessary to monitor the ability of major domestic laboratories to detect and identify exotic arbovirus infections in travelers. METHODS An external quality assessment program for the molecular detection of EEEV, VEEV, WEEV, SLEV, WNV, YFV, TBEV, HeV and NiV was organized. The assessment panel included 26 negative and positive samples with different concentrations of virus-like particles and distributed to 31 laboratories to evaluate the accuracy of virus detection. RESULTS At the laboratory level, 87.5% (7/8, EEEV), 85.7% (12/14, WEEV), 100% (13/13, VEEV), 87.5% (7/8, HeV), 76.5% (13/17, NiV), 92.6% (25/27, YFV), 81.3% (13/16, WNV), 100% (5/5, SLEV) and 75.0% (6/8, TBEV) of the participants were considered "competent". Of all the results, the false-positive and false-negative rates were 0.3% and 0.7%, respectively. The sensitivity of most detection assays (15/17, 88.2%) was more than 90%. In addition, we observed significantly different cycle threshold values when using primer-probe sets in different target regions to detect EEEV and SLEV. CONCLUSIONS Most laboratories have reliable virus detection capabilities. However, laboratory testing capabilities need to be improved to avoid cross-contamination and to better manage undetected false-negative samples.
Collapse
Affiliation(s)
- Runling Zhang
- National Center for Clinical Laboratories, Institute of Geriatric Medicine, Chinese Academy of Medical Sciences, Beijing Hospital/National Center of Gerontology, P. R. China; Graduate School of Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing, P. R. China; Beijing Engineering Research Center of Laboratory Medicine, Beijing Hospital, Beijing, P. R. China
| | - Ping Tan
- National Center for Clinical Laboratories, Institute of Geriatric Medicine, Chinese Academy of Medical Sciences, Beijing Hospital/National Center of Gerontology, P. R. China; Graduate School of Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing, P. R. China; Beijing Engineering Research Center of Laboratory Medicine, Beijing Hospital, Beijing, P. R. China
| | - Lei Feng
- National Center for Clinical Laboratories, Institute of Geriatric Medicine, Chinese Academy of Medical Sciences, Beijing Hospital/National Center of Gerontology, P. R. China; Graduate School of Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing, P. R. China; Beijing Engineering Research Center of Laboratory Medicine, Beijing Hospital, Beijing, P. R. China
| | - Rui Li
- National Center for Clinical Laboratories, Institute of Geriatric Medicine, Chinese Academy of Medical Sciences, Beijing Hospital/National Center of Gerontology, P. R. China; Graduate School of Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing, P. R. China; Beijing Engineering Research Center of Laboratory Medicine, Beijing Hospital, Beijing, P. R. China
| | - Jing Yang
- National Center for Clinical Laboratories, Institute of Geriatric Medicine, Chinese Academy of Medical Sciences, Beijing Hospital/National Center of Gerontology, P. R. China; Graduate School of Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing, P. R. China; Beijing Engineering Research Center of Laboratory Medicine, Beijing Hospital, Beijing, P. R. China
| | - Rui Zhang
- National Center for Clinical Laboratories, Institute of Geriatric Medicine, Chinese Academy of Medical Sciences, Beijing Hospital/National Center of Gerontology, P. R. China; Graduate School of Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing, P. R. China; Beijing Engineering Research Center of Laboratory Medicine, Beijing Hospital, Beijing, P. R. China.
| | - Jinming Li
- National Center for Clinical Laboratories, Institute of Geriatric Medicine, Chinese Academy of Medical Sciences, Beijing Hospital/National Center of Gerontology, P. R. China; Graduate School of Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing, P. R. China; Beijing Engineering Research Center of Laboratory Medicine, Beijing Hospital, Beijing, P. R. China.
| |
Collapse
|
8
|
AlShebly MM, AlQahtani FS, Govindarajan M, Gopinath K, Vijayan P, Benelli G. Toxicity of ar-curcumene and epi-β-bisabolol from Hedychium larsenii (Zingiberaceae) essential oil on malaria, chikungunya and St. Louis encephalitis mosquito vectors. Ecotoxicol Environ Saf 2017; 137:149-157. [PMID: 27918946 DOI: 10.1016/j.ecoenv.2016.11.028] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/24/2016] [Revised: 11/14/2016] [Accepted: 11/29/2016] [Indexed: 06/06/2023]
Abstract
Mosquitoes act as vectors of key pathogens and parasites. Plant essential oils have been recognized as important sources of biopesticides, which do not induce resistance and have limited toxic effects on human health and non-target organisms. In this research, we evaluated the larvicidal and oviposition deterrence activity of Hedychium larsenii essential oil (EO) and its major compounds ar-curcumene and epi-β-bisabolol. Both molecules showed high toxicity against early third instars of Anopheles stephensi (LC50=10.45 and 14.68µg/ml), Aedes aegypti (LC50=11.24 and 15.83µg/ml) and Culex quinquefasciatus (LC50=12.24 and 17.27µg/ml). In addition, low doses of ar-curcumene and epi-β-bisabolol were effective as oviposition deterrents against the three tested mosquito species. Notably, the acute toxicity of H. larsenii oil and its major compounds against the mosquito biocontrol agent Poecilia reticulata was low, with LC50 higher than 1500ppm. Overall, the results from this study revealed that ar-curcumene and epi-β-bisabolol from the H. larsenii oil can be considered for the development of novel and effective mosquito larvicides.
Collapse
Affiliation(s)
- Mashael Marzouq AlShebly
- Department of Obstetrics and Gynecology, College of Medicine, King Saud University and King Saud University Medical City, Riyadh, Saudi Arabia
| | - Fatma Saeed AlQahtani
- Hematology Unit, Department of Pathology, College of Medicine, King Saud University and King Saud University Medical City, Riyadh, Saudi Arabia
| | - Marimuthu Govindarajan
- Unit of Vector Control, Phytochemistry and Nanotechnology, Department of Zoology, Annamalai University, Annamalainagar 608002, Tamil Nadu, India.
| | - Kasi Gopinath
- Department of Botany, Bharathiar University, Coimbatore 641046, Tamil Nadu, India
| | - Periasamy Vijayan
- Unit of Vector Control, Phytochemistry and Nanotechnology, Department of Zoology, Annamalai University, Annamalainagar 608002, Tamil Nadu, India
| | - Giovanni Benelli
- Department of Agriculture, Food and Environment, University of Pisa, via del Borghetto 80, 56124, Pisa, Italy.
| |
Collapse
|
9
|
Diaz LA, Quaglia AI, Konigheim BS, Boris AS, Aguilar JJ, Komar N, Contigiani MS. Activity Patterns of St. Louis Encephalitis and West Nile Viruses in Free Ranging Birds during a Human Encephalitis Outbreak in Argentina. PLoS One 2016; 11:e0161871. [PMID: 27564679 PMCID: PMC5001705 DOI: 10.1371/journal.pone.0161871] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2016] [Accepted: 08/12/2016] [Indexed: 11/30/2022] Open
Abstract
St. Louis encephalitis virus (SLEV) (Flavivirus) is a reemerging arbovirus in the southern cone of South America. In 2005, an outbreak of SLEV in central Argentina resulted in 47 human cases with 9 deaths. In Argentina, the ecology of SLEV is poorly understood. Because certain birds are the primary amplifiers in North America, we hypothesized that birds amplify SLEV in Argentina as well. We compared avian SLEV seroprevalence in a variety of ecosystems in and around Córdoba city from 2004 (before the epidemic) and 2005 (during the epidemic). We also explored spatial patterns to better understand the local ecology of SLEV transmission. Because West Nile virus (WNV) was also detected in Argentina in 2005, all analyses were also conducted for WNV. A total of 980 birds were sampled for detection of SLEV and WNV neutralizing antibodies. SLEV seroprevalence in birds increased 11-fold from 2004 to 2005. Our study demonstrated that a high proportion (99.3%) of local birds were susceptible to SLEV infection immediately prior to the 2005 outbreak, indicating that the vertebrate host population was primed to amplify SLEV. SLEV was found distributed in a variety of environments throughout the city of Córdoba. However, the force of viral transmission varied among sites. Fine scale differences in populations of vectors and vertebrate hosts would explain this variation. In summary, we showed that in 2005, both SLEV and to a lesser extent WNV circulated in the avian population. Eared Dove, Picui Ground-Dove and Great Kiskadee are strong candidates to amplify SLEV because of their exposure to the pathogen at the population level, and their widespread abundance. For the same reasons, Rufous Hornero may be an important maintenance host for WNV in central Argentina. Competence studies and vector feeding studies are needed to confirm these relationships.
Collapse
Affiliation(s)
- Luis Adrián Diaz
- Laboratorio de Arbovirus—Instituto de Virología “Dr. J. M. Vanella”–Facultad de Ciencias Médicas–Universidad Nacional de Córdoba, Córdoba, Argentina
- Instituto de Investigaciones Biológicas y Tecnológicas–CONICET–Universidad Nacional de Córdoba, Córdoba, Argentina
- * E-mail:
| | - Agustín Ignacio Quaglia
- Laboratorio de Arbovirus—Instituto de Virología “Dr. J. M. Vanella”–Facultad de Ciencias Médicas–Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Brenda Salomé Konigheim
- Laboratorio de Arbovirus—Instituto de Virología “Dr. J. M. Vanella”–Facultad de Ciencias Médicas–Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Analia Silvana Boris
- Laboratorio de Arbovirus—Instituto de Virología “Dr. J. M. Vanella”–Facultad de Ciencias Médicas–Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Juan Javier Aguilar
- Laboratorio de Arbovirus—Instituto de Virología “Dr. J. M. Vanella”–Facultad de Ciencias Médicas–Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Nicholas Komar
- Centers for Diseases Control and Prevention, Fort Collins, Colorado, United States of America
| | - Marta Silvia Contigiani
- Laboratorio de Arbovirus—Instituto de Virología “Dr. J. M. Vanella”–Facultad de Ciencias Médicas–Universidad Nacional de Córdoba, Córdoba, Argentina
| |
Collapse
|
10
|
SMITH MG, BLATTNER RJ. Experiments on the role of the chicken mite, Dermanyssus gallinae. and the mosquito in the epidemiology of St. Louis encephalitis. ACTA ACUST UNITED AC 2008; 87:119-38. [PMID: 18911174 PMCID: PMC2135767 DOI: 10.1084/jem.87.2.119] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022]
Abstract
The present experimental results concern primarily the question, whether or not mosquitoes feeding on chickens having viremia, as a result of the bite of infected mites, can acquire the virus of St. Louis encephalitis and whether or not mosquitoes thus infected, can transmit the virus to chickens and hamsters. During the course of the investigation, 7 species of mosquitoes of 3 genera were infected with the virus in one or two or all of three ways: by feeding on a suspension of infected mouse brain tissue, by feeding on chickens in which viremia had been produced by subcutaneous inoculation of virus, and by feeding on chickens having viremia as a result of the bite of infected mites. These mosquitoes transmitted the virus to chickens at periods varying from 5 to 33 days after the infective meal. The virus of St. Louis encephalitis was transmitted to hamsters by Culex pipiens at periods varying from 4 to 27 days after feeding on chickens having viremia as a result of the bite of infected mites. While viremia was demonstrated readily in hamsters, signs of encephalitis did not develop. In all transmission experiments the method of chorioallantoic passage proved necessary for the demonstration of viremia. A concept of the epidemiology of St. Louis encephalitis is presented: two blood-sucking vectors may be involved, one an arachnid, the mite, maintaining the virus in nature by transovarial passage, and the other, an insect, the mosquito, which carries the infection from birds to other vertebrates including man.
Collapse
|
11
|
Abstract
This descriptive prevalence study describes the relationships between mosquito density and the presence of arboviruses (in mosquitoes and humans) with various socioeconomic and environmental factors present near the time of teh arbovirus outbreak in Harris County, Texas, in 2002. This study suggests that mosquito density increased if the trap was located in an area with a large number of containers that may inadvertently retain rainwater (P = 0.056). When considering only virus-positive mosquitoes, significant relationships were observed if the trap was located near waste materials (P < 0.001) or near containers that may inadvertently retain rainwater (P = 0.037). Furthermore, the presence of arbovirus activity (in mosquitoes or humans) in a geographic area tended to be associated with the socioeconomic status of the local community. Although the results of socioeconomic comparisons were not significant, they were suggestive, demonstrating an interesting trend. Compared with communities where virus activity was not observed, the socioeconomic status of the arbovirus-positive community was consistently lower. Specifically, results showed that the populations residing in virus-positive census tracts attained less education, earned less income per household, and were more likely to be below the poverty level. In addition, this study found that virus-positive mosquitoes were randomly distributed throughout the study area, whereas severe human infection cases were clustered. Based on the results of this study, we conclude that the health outcome of a local community as it relates to West Nile virus and St. Louis encephalitis is dependent on many factors, including eh socioeconomic and environmental characteristics of the community.
Collapse
Affiliation(s)
- Janelle Rios
- University of Texas Health Science Center, School of Public Health Management, Community Health, and Policy Division, 1200 Herman Pressler, Houston, TX 77030, USA
| | | | | | | |
Collapse
|
12
|
Reisen WK, Fang Y, Martinez VM. Avian host and mosquito (Diptera: Culicidae) vector competence determine the efficiency of West Nile and St. Louis encephalitis virus transmission. J Med Entomol 2005; 42:367-75. [PMID: 15962789 DOI: 10.1093/jmedent/42.3.367] [Citation(s) in RCA: 104] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
The ability of the invading NY99 strain of West Nile virus (WNV) to elicit an elevated viremia response in California passerine birds was critical for the effective infection of Culex mosquitoes. Of the bird species tested, Western scrub jays, Aphelocoma coerulescens, produced the highest viremia response, followed by house finches, Carpodacus mexicanus, and house sparrows, Passer domesticus. Most likely, few mourning, Zenaidura macroura, or common ground, Columbina passerine, doves and no California quail, Callipepla californica, or chickens would infect blood-feeding Culex mosquitoes. All Western scrub jays and most house finches succumbed to infection. All avian hosts produced a lower viremia response and survived after infection with an endemic strain of St. Louis encephalitis virus. Culex species varied in their susceptibility to infection with both viruses, with Culex stigmatosoma Dyar generally most susceptible, followed by Culex tarsalis Coquillett, and then Culex p. quinquefasciatus Say. Populations within Culex species varied markedly in their susceptibility, perhaps contributing to the focality of WNV amplification. Transmitting female Cx. tarsalis expectorated from six to 3,777 plaque-forming units (PFU) of WNV during transmission trials, thereby exposing avian hosts to a wide range of infectious doses. Highly susceptible house finches and moderately susceptible mourning doves were infected by subcutaneous inoculation with decreasing concentrations of WNV ranging from 15,800 to <0.3 PFU. All birds became infected and produced comparable peak viremias on days 2-3 postinoculation; however, the rise in viremia titer and onset of the acute phase of infection occurred earliest in birds inoculated with the highest doses. WNV virulence in birds seemed critical in establishing elevated viremias necessary to efficiently infect blood feeding Culex mosquitoes.
Collapse
Affiliation(s)
- W K Reisen
- Center for Vectorborne Diseases, School of Veterinary Medicine, University of California, Davis, CA 95616, USA
| | | | | |
Collapse
|
13
|
Bradford CM, Nascarella MA, Burns TH, Montford JR, Marsland EJ, Pepper CB, Presley SM. First report of West Nile virus in mosquitoes from Lubbock County, Texas. J Am Mosq Control Assoc 2005; 21:102-105. [PMID: 15825772 DOI: 10.2987/8756-971x(2005)21[102:frownv]2.0.co;2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Since July 2002, ongoing surveillance efforts have been conducted to determine potential vectors of West Nile virus (WNV) and Saint Louis encephalitis virus (SLEV) in the mosquito population occurring in Lubbock County, Texas. Adult mosquitoes collected in Lubbock County during 2002 and 2003 represented 7 genera, with Culex tarsalis and Ochlerotatus sollicitans being the predominant species collected. Mosquitoes were initially screened for WNV and SLEV by using the VecTest antigen panel assay. Positive VecTest results were confirmed by reverse transcriptase-polymerase chain reaction. West Nile virus-positive pools of mosquitoes were detected in 2002 and 2003, with the majority of the positive pools consisting of Cx. tarsalis. None of the mosquito pools tested positive for SLEV.
Collapse
Affiliation(s)
- Carrie M Bradford
- The Institute of Environmental and Human Health, Department of Environmental Toxicology, Texas Tech University, Box 41163, Lubbock, TX 79409-1163, USA
| | | | | | | | | | | | | |
Collapse
|
14
|
DUFFY CE, JORDAN RT, MEYER HM. Effect of multiple inoculations on interference between St. Louis encephalitis virus and equine encephalomyelitis virus. Exp Biol Med (Maywood) 2004; 80:279-81. [PMID: 14949023 DOI: 10.3181/00379727-80-19595] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
|
15
|
Abstract
Two simulation models were used to investigate the epidemiology of St. Louis encephalitis virus (SLEv) in south Florida, one including sentinel hosts (chickens) and amplification hosts (wild birds), while the other one included age structure in the amplification host population. The overall population size of the vector, Culex nigripalpus, was a major factor in the likelihood of epizootics for both models, but the seasonal dynamics of the vector alone did not explain variation in transmission. Interactions between seasonal factors in the mosquito and reproduction in the wild amplification avian hosts appeared to be important in the likelihood of epizootics. Biased feeding between sentinel and amplification hosts affected the time course of virus prevalence and may have implications for the interpretation of sentinel data. The time of virus introduction strongly affected the timing of outbreaks but did not affect the likelihood of epizootics. In most cases, the outbreak occurred immediately after virus introduction; however, in some cases the outbreak was delayed until the mosquito population increased. This has implications for the timing of control strategies directed against mosquito populations.
Collapse
Affiliation(s)
- C C Lord
- Florida Medical Entomology Laboratory, University of Florida-Institute of Food and Agricultural Sciences, Vero Beach, FL 32962, USA.
| | | |
Collapse
|
16
|
Abstract
West Nile virus (WNv) has spread through much of the eastern United States following its introduction in 1999, and arrived in Florida in 2001. Prior to its arrival, we anticipated that its transmission cycle was likely to be similar to that of St. Louis encephalitis virus (SLEv). However, high levels of avian mortality have been reported for WNv in the northeastern United States, and it was unknown how this would impact the transmission dynamics of WNv. Simulation models were used to compare the two viruses by considering the impact of bird mortality on the transmission dynamics of arboviruses in south Florida. Transmission models without disease-induced mortality (SLEv) were compared with models including disease-induced mortality (WNv). Disease-induced mortality depressed transmission, eliminating epizootics in two of 14 simulations that were epizootic without the additional mortality. In both models, the most important factor in the likelihood of epizootics was mosquito population size; the mosquito mortality rate was also important. The additional avian mortality altered the factors most important in the size and timing of epizootics, although it did not always directly affect the outcome of the simulations. In some cases, low-level transmission occurred prior to the epizootic peak. When disease-induced avian mortality was included in the simulations, appreciable numbers of dead birds occurred prior to high levels of infection in mosquitoes. This has implications for the use of dead birds as a surveillance tool monitoring the spread and transmission of WNv.
Collapse
Affiliation(s)
- C C Lord
- Florida Medical Entomology Laboratory, University of Florida-Institute of Food and Agricultural Sciences, Vero Beach, FL 32962, USA.
| | | |
Collapse
|
17
|
Jones SC, Morris J, Hill G, Alderman M, Ratard RC. St. Louis encephalitis outbreak in Louisiana in 2001. J La State Med Soc 2002; 154:303-6. [PMID: 12517026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 04/19/2023]
Abstract
A description of the St. Louis encephalitis (SLE) outbreak in Northeast Louisiana is presented. In the fall of 2001 there were 63 cases of St. Louis encephalitis in Monroe and West Monroe and seven additional cases in the neighboring parishes of Richland, Morehouse and Franklin. All cases had a clinical presentation of encephalitis and were confirmed serologically. Clinically most cases presented with fever, meningitis syndrome with altered mental status. Tremors were common (56% of cases). There were three deaths. Age-group distribution showed a predominance among 45 and older. The epidemic curve based on diagnosis date showed an explosive outbreak starting August 8, 2001, reaching a peak by the second week, and progressively slowing down. The curve showed that by the time the first case was diagnosed, 60% or more of the cases were already infected. Most of the cases come from low socio-economic areas. Houses were often run down, many with screens in disrepair. Backyards were usually large, with heavy brush and many trees. There was an abundance of sources of mosquito larvae, particularly for Culex quinquefasciatus which is the main vector. Mosquito pools confirmed the presence of SLE virus. As soon as the first case was reported, a campaign of health education and increased mosquito adulticiding were implemented.
Collapse
|
18
|
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.
Collapse
Affiliation(s)
- J F Day
- Florida Medical Entomology Laboratory, Institute of Food and Agricultural Sciences, University of Florida, Vero Beach, Florida 32962, USA.
| |
Collapse
|
19
|
Pietrantonio PV, Gibson G, Nawrocki S, Carrier F, Knight WP. Insecticide resistance status, esterase activity, and electromorphs from mosquito populations of Culex quinquefasciatus Say (Diptera: Culicidae), in Houston (Harris County), Texas. J Vector Ecol 2000; 25:74-89. [PMID: 10925799] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Culex quinquefasciatus Say is a vector of St. Louis encephalitis (SLE) in Texas. This disease is endemic and prevalent in the Houston area. Disease prevention through mosquito control is mainly targeted against adults by application of a resmethrin-piperonyl butoxide formulation (Scourge). Immature mosquitoes were collected from eight areas in Harris County during 1998. The susceptibility status of these populations to Scourge, malathion, and resmethrin, the latter alone or with an esterase inhibitor as a synergist, was determined using a bottle assay with females. The population structure was investigated by electrophoretic analysis of esterases and their activity. Individual females were also analyzed for esterase activity by plate assay and for isoenzyme pattern by native PAGE. Bioassays indicated high levels of resistance to malathion in all areas. In addition, the effectiveness of Scourge in mosquitoes from area 51 deteriorated throughout the season. A localized, distinctive esterase pattern and activity level was observed in mosquitoes from different areas. Overall, the frequency of esterases Est alpha 2 (A2)/Est beta 2 (B2) was higher than that of Est beta 1 (B1). Altogether, these results indicate the onset of a fragile situation for mosquito control that should be further analyzed to effectively maintain the SLE prevention program for Harris County.
Collapse
Affiliation(s)
- P V Pietrantonio
- Department of Entomology, Texas A&M University, College Station 77843-2475, USA
| | | | | | | | | |
Collapse
|
20
|
Wasay M, Diaz-Arrastia R, Suss RA, Kojan S, Haq A, Burns D, Van Ness P. St Louis encephalitis: a review of 11 cases in a 1995 Dallas, Tex, epidemic. Arch Neurol 2000; 57:114-8. [PMID: 10634457 DOI: 10.1001/archneur.57.1.114] [Citation(s) in RCA: 63] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
OBJECTIVE To update some of the clinical features of St Louis encephalitis (SLE), a common arboviral infection that occurs in epidemic patterns in the south-central and midwestern United States. METHODS Eleven patients with SLE from a 1995 epidemic in Dallas, Tex, were studied clinically, radiologically, neurophysiologically, and neuropathologically (in 1 case). RESULTS The electroencephalograms and magnetic resonance imaging (MRI) scans of our patients revealed features that have received little attention in previous studies. Of the 9 patients who were examined with electroencephalography, all 9 had seizures or other abnormalities, and 1 had nonconvulsive status epilepticus. Two of 6 patients who had MRIs showed substantia nigra edema. Finally, 2 (18%) of our patients had coinfection with the human immunodeficiency virus. CONCLUSIONS The MRI findings of substantia nigra edema in patients with SLE have not been previously reported. Nonconvulsive status epilepticus can occur in patients with SLE and should be considered in patients with prolonged encephalopathy. Finally, human immunodeficiency virus coinfection may be a risk factor for symptomatic SLE infection.
Collapse
Affiliation(s)
- M Wasay
- Department of Neurology, University of Texas Southwestern Medical School, Dallas, USA
| | | | | | | | | | | | | |
Collapse
|
21
|
Day JF, Curtis GA. Blood feeding and oviposition by Culex nigripalpus (Diptera: Culicidae) before, during, and after a widespread St. Louis encephalitis virus epidemic in Florida. J Med Entomol 1999; 36:176-181. [PMID: 10083754 DOI: 10.1093/jmedent/36.2.176] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
A widespread epidemic of St. Louis encephalitis (SLE) virus was reported from central Florida from late July through December 1990 with 226 clinical cases and 11 deaths in humans. The abundance of blood-fed and gravid Culex nigripalpus Theobald females, the vector of SLE in Florida, was monitored at a resting site in Indian River County, FL, for the 3 yr before the epidemic, the epidemic year, and for 1 yr following the epidemic. Each study year was divided into four 3-mo periods that depict the subtropical SLE transmission cycle; a January-March maintenance phase, an April-June amplification phase, a July-September early transmission phase, and an October-December late transmission phase. The abundance of blood-fed and gravid females was significantly greater during the amplification, early transmission, and late transmission phases of the 1990 SLE epidemic when compared with the 3 pre-epidemic years. Throughout the study, Cx. nigripalpus blood feeding and oviposition was driven by epic (> 50 mm) rainfall events. The abundance of gravid females decreased, whereas the number of blood-fed females increased following heavy rainfalls. Epizootic and epidemic transmission of SLE to sentinel chickens and humans in Indian River County was greatest immediately following heavy rainfalls that synchronized Cx. nigripalpus oviposition and blood feeding.
Collapse
Affiliation(s)
- J F Day
- Florida Medical Entomology Laboratory, University of Florida, Vero Beach 32962, USA
| | | |
Collapse
|
22
|
Reisen WK, Hardy JL, Presser SB. Effects of water quality on the vector competence of Culex tarsalis (Diptera: Culicidae) for western equine encephalomyelitis (Togaviridae) and St. Louis encephalitis (Flaviviridae) viruses. J Med Entomol 1997; 34:631-643. [PMID: 9439117 DOI: 10.1093/jmedent/34.6.631] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
The effects of water quality during immature development on the vector competence of adult female Culex tarsalis Coquillett for western equine encephalomyelitis (WEE) and St. Louis encephalitis (SLE) viruses was evaluated during 6 field and 4 laboratory experiments. Immatures of the Bakersfield Field Station laboratory strain and the F1 progeny of field-collected females were reared in the field or laboratory and then infected by feeding on pledgets, after which remnants (head, thorax, abdomen), legs, and salivary secretions were tested for WEE or SLE virus to estimate infection, dissemination, and transmission rates, respectively. Although the salt content of the 6 larval habitats varied markedly (range, alkalinity 160-1,310 ppm CaCO3, conductivity 460-7,600 microns hos/cm, chlorides 22-1,560 ppm) and significantly altered immature survival, development time, and female body size (wing length), consistent changes in infection, dissemination, or transmission rates were not observed. Susceptibility (ID50) to WEE virus in field strains decreased as a linear function of developmental time, with populations from a dry alkali lake bed (Goose Lake) least susceptible. Three subsequent laboratory experiments that tested the effects of rearing immatures in dilution series of water from Goose Lake failed to produce consistent within or among experiment patterns in vector competence. A 4th laboratory experiment tested changes in NaCl concentration with negative results. Changes in female size was not related to vector competence. These and previous temperature studies indicated that temporal changes in vector competence observed within and among field populations probably were related to intrinsic genetic factors and were not related directly to extrinsic factors in the immature aquatic environment.
Collapse
Affiliation(s)
- W K Reisen
- Division of Epidemiology and Public Health Biology, School of Public Health, University of California, Berkeley 94720, USA
| | | | | |
Collapse
|
23
|
DOW RP, COLEMAN PH, MEADOWS KE, WORK TH. ISOLATION OF ST. LOUIS ENCEPHALITIS VIRUSES FROM MOSQUITOES IN THE TAMPA BAY AREA OF FLORIDA DURING THE EPIDEMIC OF 1962. Am J Trop Med Hyg 1996; 13:462-8. [PMID: 14159986 DOI: 10.4269/ajtmh.1964.13.462] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
|
24
|
Abstract
Diseases caused by flavivirus infection have been a scourge of mankind for over three centuries; with yellow fever, dengue fever and Russian spring-summer encephalitis causing epidemics resulting in thousands of fatalities. Due to the development of a safe and efficacious live-attenuated vaccine against yellow fever, this disease is no longer such a threat in countries where adequate vaccination is practised. A similarly safe and efficacious inactivated vaccine against central-European tick-borne encephalitis has also been developed and this has drastically reduced the incidence of this disease in many countries where it is endemic. In spite of these successes, the development of vaccines against other pathogenic flaviviruses, causing diseases such as dengue fever and Russian spring-summer encephalitis, have not been successful. This review attempts to summarize the development of flavivirus vaccines to date and identify areas for future improvements. Problems associated with designing flavivirus vaccines are discussed and the advantages and disadvantages of future strategies for vaccine development are considered.
Collapse
Affiliation(s)
- J R Stephenson
- Division of Biologics, Centre for Applied Microbiology and Research, Porton Down, Salisbury, UK
| |
Collapse
|
25
|
MESH Headings
- Animals
- Arboviruses
- Culicidae/microbiology
- Encephalitis Virus, California
- Encephalitis Virus, St. Louis
- Encephalitis Virus, Western Equine
- Encephalitis Viruses
- Encephalitis, Arbovirus/epidemiology
- Encephalitis, Arbovirus/history
- Encephalitis, Arbovirus/transmission
- Encephalitis, St. Louis/epidemiology
- Encephalitis, St. Louis/history
- Encephalitis, St. Louis/transmission
- Encephalomyelitis, Equine/epidemiology
- Encephalomyelitis, Equine/history
- Encephalomyelitis, Equine/transmission
- History, 20th Century
- Humans
- Insect Vectors/microbiology
- Research
- United States
Collapse
Affiliation(s)
- W C Reeves
- Department of Biomedical and Environmental Health Sciences, School of Public Health, University of California, Berkeley 94720
| |
Collapse
|
26
|
Sabattini MS, Monath TP, Mitchell CJ, Daffner JF, Bowen GS, Pauli R, Contigiani MS. Arbovirus investigations in Argentina, 1977-1980. I. Historical aspects and description of study sites. Am J Trop Med Hyg 1985; 34:937-44. [PMID: 4037184] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
This is the introductory paper to a series on the ecology of arboviruses in Argentina. Epizootics of equine encephalitis have occurred since at least 1908, principally in the Pampa and Espinal biogeographic zones, with significant economic losses; human cases of encephalitis have been rare or absent. Both western equine and eastern equine encephalitis viruses have been isolated from horses during these epizootics, but the mosquitoes responsible for transmission have not been identified. A number of isolations of Venezuelan equine encephalitis (VEE) virus were reported between 1936 and 1958 in Argentina, but the validity of these findings has been seriously questioned. Nevertheless, serological evidence exists for human infections with a member of the VEE virus complex. Serological surveys conducted in the 1960s indicate a high prevalence of infection of humans and domestic animals with St. Louis encephalitis (SLE), and 2 SLE virus strains have been isolated from rodents. Human disease, however, has rarely been associated with SLE infection. Only 7 isolations of other arboviruses have been described (3 of Maguari, 1 of Aura, 2 of Una, and 1 of an untyped Bunyamwera group virus). In 1977, we began longitudinal field studies in Santa Fe Province, the epicenter of previous equine epizootics, and in 1980 we extended these studies to Chaco and Corrientes provinces. The study sites are described in this paper.
Collapse
MESH Headings
- Animals
- Arbovirus Infections/epidemiology
- Arbovirus Infections/microbiology
- Arboviruses
- Argentina
- Birds
- Cattle
- Child
- Climate
- Ecology
- Encephalitis Virus, St. Louis
- Encephalitis Virus, Venezuelan Equine
- Encephalitis Virus, Western Equine
- Encephalitis, St. Louis/epidemiology
- Encephalitis, St. Louis/microbiology
- Encephalomyelitis, Equine/epidemiology
- Encephalomyelitis, Equine/microbiology
- Encephalomyelitis, Equine/veterinary
- Encephalomyelitis, Venezuelan Equine/epidemiology
- Encephalomyelitis, Venezuelan Equine/microbiology
- Encephalomyelitis, Venezuelan Equine/veterinary
- Geography
- Horse Diseases/epidemiology
- Horse Diseases/microbiology
- Horses/microbiology
- Humans
Collapse
|
27
|
Abstract
Distribution of DOPA-oxidase isozymes in larval Culex pipiens pipiens, Culex pipiens quinquefasciatus and their hybrids was determined by agarose gel electrophoresis. Three zones of enzyme activity were detected in the subspecific and hybrid populations. Zone I was cathodic whereas Zones II and III were anodic. Electrophoretic variability was evident only in Zone II which was dimorphic for enzyme activity. Zones I and III were monomorphic. The subspecific and hybrid populations were distinguishable from one another only in Zone II. In all three populations, melanization was most intense in Zone II, less in Zone I, and least in Zone III.
Collapse
|
28
|
Hardy JL, Rosen L, Reeves WC, Scrivani RP, Presser SB. Experimental transovarial transmission of St. Louis encephalitis virus by Culex and Aedes mosquitoes. Am J Trop Med Hyg 1984; 33:166-75. [PMID: 6696174 DOI: 10.4269/ajtmh.1984.33.166] [Citation(s) in RCA: 30] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Colonized and field-collected female Culex tarsalis, infected with St. Louis encephalitis, (SLE) virus by intrathoracic inoculation or by feeding on a viremic host, transmitted virus to their F1 adult and/or larval progeny when reared at 18(+/- 1) degree C but not when reared at 27(+/- 1) degrees C. The minimal infection rates (MIR) for different populations of Cx. tarsalis ranged from 1:32 to less than 1:250 (mean = 1:121) for larval progeny and from 1:32 to less than 1:1, 989 (mean = 1:1,571) for adult progeny. SLE virus also was transmitted transovarially by colonized and field-collected populations of Culex pipiens (mean MIRs = 1:340 and 1:1,815 for larval and adult progeny, respectively) and by a field population of Culex quinquefasciatus (MIR = 1:500 and less than 1:246 for larval and adult progeny, respectively), but not by colonized strains of Cx. quinquefasciatus and Culex peus. SLE virus was not recovered in tests on 5,522 Cx. tarsalis and 4,798 Cx. quinquefasciatus that were collected as larvae or pupae from field sites in Southern California and reared to adults at 18 degrees C in the laboratory. Transovarial transmission of SLE virus by Aedes epactius was confirmed and extended to a closely related species, Aedes atropalpus. Efforts to demonstrate transovarial transmission of SLE virus by Aedes melanimon, Aedes sierrensis, and Aedes triseriatus were unsuccessful. Aedes dorsalis, Cx. peus, and Toxorhynchites amboinensis were equally sensitive hosts for viral isolation when inoculated with suspensions of larvae transovarially infected with SLE virus.
Collapse
|
29
|
Abstract
Comparisons were made between groups of Culex pipiens L. with different physiologic histories to test their ability to sucessfully overwinter under field conditions. On 14 December 1978, each group of mosquitoes was marked with a distinctive fluorescent dust and released inside an abandoned ammunition bunker at Fort Washington, Maryland. To insure that dead mosquitoes could be dissected and information obtained on their ovarian development, a sample of females from each group was also released into a plexiglass cage that was attached to the inside wall of the room. The physiologic histories of each group of mosquitoes were as follows: (a) "wild caught", those which had entered the bunker prior to the release date, (b) "lab-reared diapausing nonblood-fed," (c) "lab-reared diapausing blood-fed nongravid, " (d)"lab-reared diapausing blood-fed gravid," (e) "lab-reared nondiapausing nonblood-fed," and (f) "lab-reared nondiapausing blood-fed." By 8 March 1979, all of the lab-reared nondiapausing groups, of mosquitoes released in the room had died, whereas 15.7, 22.4 and 24.7% were recovered from the "lab-reared diapausing nonblood-fed," "lab-reared diapausing blood-fed" (gravid and nongravid) and "wild caught" mosquitoes, respectively. For the mosquitoes in the cage, only 0, 2.1 and 7.0% of the "lab-reared nondiapausing blood-fed," "lab-reared nondiapausing nonblood-fed" and "lab-reared diapausing blood-fed gravid," respectively, survived. This compared to 45.4, 56.8 and 58.0%, respectively, for the "lab-reared diapausing nonblood-fed," "lab-reared diapausing blood-fed nongravid" and the "wild caught" groups. These data provide evidence to support the theory that a significant number of diapausing Cx. pipiens which have taken a prehibernation (possibly viremic) blood meal do not develop eggs and can survive the winter at rates comparable to diapausing nonblood-fed mosquitoes.
Collapse
|
30
|
Kuno G. Replication of dengue, yellow fever, St. Louis encephalitis and vesicular stomatitis viruses in a cell line (TRA-171) derived from Toxorhynchites amboinensis. In Vitro 1981; 17:1011-5. [PMID: 6119288 DOI: 10.1007/bf02618427] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
The replication of seven arboviruses in a cell line (TRA-171) derived from a nonhematophagous mosquito was studied. Four serotypes of laboratory adapted and three serotypes of unadapted dengue viruses replicated in the TRA-171 cell line, inducing syncytia. The sensitivity of TRA-171 cells to dengue virus infection was comparable to that of Aedes albopictus or A. pseudoscutellaris cells. Yellow fever, St. Louis encephalitis, and vesicular stomatitis viruses also replicated. All four serotypes of dengue viruses could be plaque assayed with TRA-171 cell cultures.
Collapse
|
31
|
Mitchell CJ, Monath TP, Sabattini MS. Transmission of St. Louis encephalitis virus from Argentina by mosquitoes of the Culex pipiens (Diptera: Culicidae) complex. J Med Entomol 1980; 17:282-285. [PMID: 7401124 DOI: 10.1093/jmedent/17.3.282] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
|
32
|
Hudson BW, Wolff K, DeMartini JC. Delayed-type hypersensitivity responses in mice infected with St. Louis encephalitis virus: kinetics of the response and effects of immunoregulatory agents. Infect Immun 1979; 24:71-6. [PMID: 378848 PMCID: PMC414263 DOI: 10.1128/iai.24.1.71-76.1979] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Labeled monocyte infiltration techniques have been used to study delayed-type hypersensitivity responses in mice immunized with St. Louis encephalitis virus. A delayed 24- to 48-h inflammatory response occurred 6 to 7 days after immunization. This response can be potentiated by cyclophosphamide treatment, by BCG administration, or by splenectomy. Treatments known to selectivity inhibit T-cell function suppressed the response.
Collapse
|
33
|
Emel'ianov BA, Novokhatskiĭ AS. [Reproduction and interferogenic activity of togaviruses]. Vopr Virusol 1977:216-22. [PMID: 898898] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
A comparative study of the correlation between reproduction and the interferon-inducing activity of viruses in chick embryo fibroblast cultures was carried out with members of different groups of togaviruses: alphavirus (Venezuelan equin encephalomyelitis viru, VEE) and flavivirus (Saint Louis encephalitis virus, SLE). The correspondence between cycles of accumulation of intracellular and extracellular viruses and the dynamics of interferon production the synthesis of which began early in the stage of exponential virus growth and correlated with the dynamics of their reproduction, was determined. Reproduction of the viruses was found to be directly dependent upon the multiplicity of infection; optimal infecting doses for the induction of the largest amounts of interferon were established. The calculations of the reproductive activity of VEE and SLE viruses showed their yield per one cell to be approximately 10,000 PFU and 1,000 LD50, respectively. Partial thermal inactivation of the viruses resulted in decreased yields of the infectious virus and interferon production. The regimen of thermal inactivation at which infectivity was lost completely, but the interferon-inducing capacity was retained probably due to residual synthesis of viral RNA was established for VEE virus. From the fact that the pattern of realization of genetic information is similar for both viruses, a similar mechanism of interferon synthesis induction is assumed.
Collapse
|
34
|
Watts DM, Eldridge BF. Transovarial transmission of arboviruses by mosquitoes: a review. Med Biol 1975; 53:271-8. [PMID: 1207183] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
One interesting aspect of mosquito-borne arboviruses is their endemic persistence, espeically during adverse climatic conditions in the temperate zones. The hypothesis that transovarial transmission of alpha- and flaviviruses by their respective mosquito vectors could serve as an overwintering mechanism has been proposed; however, experimental data in support of this hypothesis are not very convincing. Recently, some of the California encephalitis group arboviruses have been shown to be transmitted transovarially by Aedes species mosquitoes, and studies indicate that this mechanism contributes to the natural maintenance cycle of these viruses. Finally, consideration is given to the possibility that transovarial transmission may be unique to the California encephalitis group arboviruses and may be related to their association with a vector that overwinters in the egg stage of its life cycle.
Collapse
|
35
|
Grossberg SE, Frerman FE, Lengle EE, Roch LA, Hron WT, Dixon M. Viral infection and lipemia: a problem of disordered host physiology. J Reticuloendothel Soc 1974; 15:334-41. [PMID: 4366424] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
|
36
|
Holden P, Hayes RO, Mitchell CJ, Francy DB, Lazuick JS, Hughes TB. House sparrows, Passer domesticus (L.), as hosts of arboviruses in Hale County, Texas. I. Field studies, 1965-1969. Am J Trop Med Hyg 1973; 22:244-53. [PMID: 4688420 DOI: 10.4269/ajtmh.1973.22.244] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
|
37
|
Abstract
The virion polypeptides of eight group B arboviruses were compared by polyacrylamide gel coelectrophoresis. All contained three polypeptides, V-1, V-2, and V-3. The mosquito-borne viruses had electrophoretically similar small membrane polypeptides (V-1); the tick-borne viruses had a V-1 of significantly decreased mobility.
Collapse
|
38
|
Luby JP, Sanders CV, Johanson WG, McCubbin JH, Barnett JA, Sanford JP, Sulkin SE. Trinity River serologic survey. A survey of residents of communities along the course of the Trinity River between Houston and Dallas, Texas, for antibodies to the viruses of St. Louis encephalitis, western equine encephalitis and California encephalitis. Am J Epidemiol 1971; 94:479-86. [PMID: 5120543 DOI: 10.1093/oxfordjournals.aje.a121345] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
|
39
|
Emel'ianov BA, Uryvaev LV. [The mechanism of interferon induction and its effect in tissue culture arbovirus infections]. Vopr Virusol 1971; 16:333-9. [PMID: 5167615] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
|
40
|
|
41
|
|
42
|
|
43
|
FROESCHLE JE, REEVES WC. SEROLOGIC EPIDEMIOLOGY OF WESTERN EQUINE AND ST. LOUIS ENCEPHALITIS VIRUS INFECTION IN CALIFORNIA. II. ANALYSIS OF INAPPARENT INFECTIONS IN RESIDENTS OF AN ENDEMIC AREA. Am J Epidemiol 1965; 81:44-51. [PMID: 14246080 DOI: 10.1093/oxfordjournals.aje.a120496] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
|
44
|
CHAMBERLAIN RW, SUDIA WD, GOGEL RH. STUDIES ON TRANSOVARIAL TRANSMISSION OF ST. LOUIS ENCEPHALITIS VIRUS BY CULEX QUINQUEFASCIATUS SAY. Am J Epidemiol 1964; 80:254-65. [PMID: 14215836 DOI: 10.1093/oxfordjournals.aje.a120474] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
|
45
|
LEWIS AL, JENNINGS WL, SCHNEIDER NJ. The First Isolation of St. Louis Encephalitis Virus from Mosquitoes in Florida. Exp Biol Med (Maywood) 1964; 116:961-3. [PMID: 14232042 DOI: 10.3181/00379727-116-29421] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
|
46
|
|
47
|
|
48
|
|
49
|
GAINER JH, WINKLER WG, LEWIS AL, JENNINGS WL, COLEMAN PH. Isolations of St. Louis Encephalitis Virus from Domestic Pigeons, Columba Livia. Am J Trop Med Hyg 1964; 13:472-4. [PMID: 14159988 DOI: 10.4269/ajtmh.1964.13.472] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
|
50
|
SULKIN SE, SIMS R, ALLEN R. STUDIES OF ARTHROPOD-BORNE VIRUS INFECTIONS IN CHIROPTERA. II. EXPERIMENTS WITH JAPANESE B AND ST. LOUIS ENCEPHALITIS VIRUSES IN THE GRAVID BAT. EVIDENCE OF TRANSPLACENTAL TRANSMISSION. Am J Trop Med Hyg 1964; 13:475-81. [PMID: 14162904] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/25/2023] Open
|