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Scott C. Weaver - One of the best experts on this subject based on the ideXlab platform.
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Enzootic mosquito vector species at equine encephalitis transmission foci in the republica de panama
PLOS ONE, 2017Co-Authors: Rolando Torres, Scott C. Weaver, Rafael Samudio, Jeanpaul Carrera, Josue Young, R Marquez, Lisbeth Amarilis Hurtado, Luis Fernando Chaves, Robert B Tesh, Lorenzo CaceresAbstract: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 Republica de Panama. We sampled adult mosquitoes during the dry and rainy season of Panama. 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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V Enezuelan E Quine E Ncephalitis *
Annual Review of Entomology, 2004Co-Authors: Scott C. Weaver, Jorge Boshell, Roberto Barrera, Carlo Ferro, Juan Carlos NavarroAbstract:Venezuelan equine encephalitis virus (VEEV) remains a naturally emerging disease threat as well as a highly developed biological weapon. Recently, progress has been made in understanding the complex ecological and viral genetic mechanisms that coincide in time and space to generate outbreaks. Enzootic, equine avirulent, serotype ID VEEV strains appear to alter their serotype to IAB or IC, and their vertebrate and mosquito host range, to mediate repeated VEE emergence via mutations in the E2 envelope glycoprotein that represent convergent evolution. Adaptation to equines results in highly efficient amplification, which results in human disease. Although epizootic VEEV strains are opportunistic in their use of mosquito vectors, the most widespread outbreaks appear to involve specific adaptation to Ochlerotatus taeniorhynchus, the most common vector in many coastal areas. In contrast, Enzootic VEEV strains are highly specialized and appear to utilize vectors exclusively in the Spissipes section of the Culex (Melanoconion) subgenus.
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generation and characterization of closely related epizootic and Enzootic infectious cdna clones for studying interferon sensitivity and emergence mechanisms of venezuelan equine encephalitis virus
Journal of Virology, 2004Co-Authors: Michael Anishchenko, Slobodan Paessler, Ivorlyne P Greene, Patricia V Aguilar, Anne Sophie Carrara, Scott C. WeaverAbstract: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.
Marcelo De Las Heras - One of the best experts on this subject based on the ideXlab platform.
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characterization of Enzootic nasal tumour virus of goats complete sequence and tissue distribution
Journal of General Virology, 2003Co-Authors: A Ortin, C Cousens, E Minguijon, Michael J Sharp, Zoraida Pascual, Maider Perez De Villarreal, Marcelo De Las HerasAbstract:The complete genome sequence of a new isolate of Enzootic nasal tumour virus (ENTV-2), associated with Enzootic nasal adenocarcinoma (ENA) of goats, was determined. The genome exhibits a genetic organization characteristic of β-retroviruses. ENTV-2 is closely related to the retrovirus (ENTV-1) associated with Enzootic adenocarcinoma of sheep, and to jaagsiekte retrovirus. The main sequence differences between these viruses reside in orfX, the U3 LTR, two small regions in gag and the transmembrane (TM) region of env. Sequence analysis of the TM region of env from several sheep and goats naturally affected by ENA suggested that ENTV-1 and ENTV-2 are distinct viruses rather than geographical variants. Although both viruses transform secretory epithelial cells of the ethmoid turbinate, the study of their tissue distribution using specific PCRs showed that ENTV-2 establishes a disseminated lymphoid infection whereas ENTV-1 is mainly confined to the tumour.
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complete sequence of Enzootic nasal tumor virus a retrovirus associated with transmissible intranasal tumors of sheep
Journal of Virology, 1999Co-Authors: C Cousens, E Minguijon, Robert G Dalziel, A Ortin, Mercedes Garcia, Jane Park, Lorenzo Gonzalez, Michael J Sharp, Marcelo De Las HerasAbstract:The sequence of the complete genome of ovine Enzootic nasal tumor virus, an exogenous retrovirus associated exclusively with contagious intranasal tumors of sheep, was determined. The genome is 7,434 nucleotides long and exhibits a genetic organization characteristic of type B and D oncoviruses. Enzootic nasal tumor virus is closely related to the Jaagsiekte sheep retrovirus and to sheep endogenous retroviruses.
Scott R Walsh - One of the best experts on this subject based on the ideXlab platform.
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construction of a molecular clone of ovine Enzootic nasal tumor virus
Virology Journal, 2016Co-Authors: Scott R Walsh, Maria Carla Rosales Gerpe, Sarah K WoottonAbstract:Background Enzootic nasal tumor virus (ENTV-1) is an ovine betaretrovirus that has been linked to Enzootic nasal adenocarcinoma (ENA), a contagious tumor of the ethmoid turbinates of sheep. Transmission experiments performed using virus isolated from cell free nasal tumor homogenates suggest that ENTV-1 is the causative agent of ENA; however, this etiological relationship has not been conclusively proven due to the fact that the virus cannot be propagated in vitro nor is there an infectious molecular clone of the virus.
C Cousens - One of the best experts on this subject based on the ideXlab platform.
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Coexistence of Enzootic Nasal Adenocarcinoma and Jaagsiekte Retrovirus Infection in Sheep
Journal of Comparative Pathology, 2004Co-Authors: A Ortin, C Cousens, E Minguijon, J. M. Sharp, M. Pérez De Villarreal, M. De Las HerasAbstract:Ten sheep naturally affected with Enzootic nasal adenocarcinoma (ENA), a disease associated with ovine Enzootic nasal tumour virus (ENTV-1), were found also to be infected with jaagsiekte sheep retrovirus (JSRV), the causal agent of ovine pulmonary adenocarcinoma (OPA). Only one of the sheep showed OPA lung lesions. The animals belonged to 10 flocks located in a geographical area in which OPA is frequently seen. ENTV-1 was found in all the ENA tumours but only occasionally in extra-tumoral sites, confirming the results of a previous study. In contrast, JSRV had a disseminated tissue distribution, similar to that previously reported for animals infected with JSRV. However, the occurrence of JSRV in lymphoid tissues was clearly greater than in sheep infected with JSRV but with no lesions of ENA. The data suggested a synergistic relationship between ENTV-1 and JSRV, resulting in increased proliferation of JSRV.
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characterization of Enzootic nasal tumour virus of goats complete sequence and tissue distribution
Journal of General Virology, 2003Co-Authors: A Ortin, C Cousens, E Minguijon, Michael J Sharp, Zoraida Pascual, Maider Perez De Villarreal, Marcelo De Las HerasAbstract:The complete genome sequence of a new isolate of Enzootic nasal tumour virus (ENTV-2), associated with Enzootic nasal adenocarcinoma (ENA) of goats, was determined. The genome exhibits a genetic organization characteristic of β-retroviruses. ENTV-2 is closely related to the retrovirus (ENTV-1) associated with Enzootic adenocarcinoma of sheep, and to jaagsiekte retrovirus. The main sequence differences between these viruses reside in orfX, the U3 LTR, two small regions in gag and the transmembrane (TM) region of env. Sequence analysis of the TM region of env from several sheep and goats naturally affected by ENA suggested that ENTV-1 and ENTV-2 are distinct viruses rather than geographical variants. Although both viruses transform secretory epithelial cells of the ethmoid turbinate, the study of their tissue distribution using specific PCRs showed that ENTV-2 establishes a disseminated lymphoid infection whereas ENTV-1 is mainly confined to the tumour.
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complete sequence of Enzootic nasal tumor virus a retrovirus associated with transmissible intranasal tumors of sheep
Journal of Virology, 1999Co-Authors: C Cousens, E Minguijon, Robert G Dalziel, A Ortin, Mercedes Garcia, Jane Park, Lorenzo Gonzalez, Michael J Sharp, Marcelo De Las HerasAbstract:The sequence of the complete genome of ovine Enzootic nasal tumor virus, an exogenous retrovirus associated exclusively with contagious intranasal tumors of sheep, was determined. The genome is 7,434 nucleotides long and exhibits a genetic organization characteristic of type B and D oncoviruses. Enzootic nasal tumor virus is closely related to the Jaagsiekte sheep retrovirus and to sheep endogenous retroviruses.
A Ortin - One of the best experts on this subject based on the ideXlab platform.
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Enzootic nasal adenocarcinoma in sheep: An update
Small Ruminant Research, 2019Co-Authors: M. De Las Heras, A Ortin, M. Borobia, T. NavarroAbstract:Abstract Enzootic nasal adenocarcinoma of sheep (ENAS) is a contagious tumor of the ethmoid turbinate mucosa. The disease occurs naturally in all continents except Australia and New Zealand. Similar disease has been described in goats. ENAS is aetiologically associated with Enzootic nasal tumor virus 1 (ENTV-1) a type Beta retrovirus and closely related to jaagsiekte sheep retrovirus (JSRV) and Enzootic nasal adenocarcinoma virus of goats (ENTV-2). Clinical signs include continuous nasal discharge, respiratory distress, exophtalmus and skull deformations. The tumors have been classified histologically as low grade adenocarcinoma. ENTV-1 can be demonstrated in tumors by immunohistochemistry using several antisera developed against JSRV antigens which cross-react with ENTV-1 ones. ENTV-1 shares a oncogenic mechanisms with JSRV and ENTV-2 and active replication of the virus is required because oncogenic proprieties are associated with env gene products. Information about immune reactions in relation to ENTV-1 is scarce and controversial. Some early studies indicated absence of immune reaction although more recent studies have detected the presence of neutralizing antibodies in sheep with tumors and in contact sheep. However, the sensitivity and specificity of these tests are very low to be used in field studies. Several specific PRC techniques are available to detect viral genome in tissues and tumors. ENTV-1 can be detected in nasal secretion but is rarely found out of the tumor. The utility of PCR tests in control or eradication plans is discussed.
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Coexistence of Enzootic Nasal Adenocarcinoma and Jaagsiekte Retrovirus Infection in Sheep
Journal of Comparative Pathology, 2004Co-Authors: A Ortin, C Cousens, E Minguijon, J. M. Sharp, M. Pérez De Villarreal, M. De Las HerasAbstract:Ten sheep naturally affected with Enzootic nasal adenocarcinoma (ENA), a disease associated with ovine Enzootic nasal tumour virus (ENTV-1), were found also to be infected with jaagsiekte sheep retrovirus (JSRV), the causal agent of ovine pulmonary adenocarcinoma (OPA). Only one of the sheep showed OPA lung lesions. The animals belonged to 10 flocks located in a geographical area in which OPA is frequently seen. ENTV-1 was found in all the ENA tumours but only occasionally in extra-tumoral sites, confirming the results of a previous study. In contrast, JSRV had a disseminated tissue distribution, similar to that previously reported for animals infected with JSRV. However, the occurrence of JSRV in lymphoid tissues was clearly greater than in sheep infected with JSRV but with no lesions of ENA. The data suggested a synergistic relationship between ENTV-1 and JSRV, resulting in increased proliferation of JSRV.
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characterization of Enzootic nasal tumour virus of goats complete sequence and tissue distribution
Journal of General Virology, 2003Co-Authors: A Ortin, C Cousens, E Minguijon, Michael J Sharp, Zoraida Pascual, Maider Perez De Villarreal, Marcelo De Las HerasAbstract:The complete genome sequence of a new isolate of Enzootic nasal tumour virus (ENTV-2), associated with Enzootic nasal adenocarcinoma (ENA) of goats, was determined. The genome exhibits a genetic organization characteristic of β-retroviruses. ENTV-2 is closely related to the retrovirus (ENTV-1) associated with Enzootic adenocarcinoma of sheep, and to jaagsiekte retrovirus. The main sequence differences between these viruses reside in orfX, the U3 LTR, two small regions in gag and the transmembrane (TM) region of env. Sequence analysis of the TM region of env from several sheep and goats naturally affected by ENA suggested that ENTV-1 and ENTV-2 are distinct viruses rather than geographical variants. Although both viruses transform secretory epithelial cells of the ethmoid turbinate, the study of their tissue distribution using specific PCRs showed that ENTV-2 establishes a disseminated lymphoid infection whereas ENTV-1 is mainly confined to the tumour.
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complete sequence of Enzootic nasal tumor virus a retrovirus associated with transmissible intranasal tumors of sheep
Journal of Virology, 1999Co-Authors: C Cousens, E Minguijon, Robert G Dalziel, A Ortin, Mercedes Garcia, Jane Park, Lorenzo Gonzalez, Michael J Sharp, Marcelo De Las HerasAbstract:The sequence of the complete genome of ovine Enzootic nasal tumor virus, an exogenous retrovirus associated exclusively with contagious intranasal tumors of sheep, was determined. The genome is 7,434 nucleotides long and exhibits a genetic organization characteristic of type B and D oncoviruses. Enzootic nasal tumor virus is closely related to the Jaagsiekte sheep retrovirus and to sheep endogenous retroviruses.
