VENEZUELAN EQUINE ENCEPHALITIS

Abstract

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.

Direct and indirect pro-inflammatory cytokine response resulting from TC-83 infection of glial cells

“…Venezuelan equine encephalitis virus (VEEV) is a neurotropic virus that causes periodic outbreaks of febrile and neurological disease in the Americas [1]. VEEV is an important human and equine pathogen that is transmitted by mosquitoes, with recent outbreaks involving thousands of human and equine cases spread over large geographical regions [1].…”

“…VEEV is an important human and equine pathogen that is transmitted by mosquitoes, with recent outbreaks involving thousands of human and equine cases spread over large geographical regions [1]. VEEV is a single-stranded, positive-sense RNA virus belonging to the genus Alphavirus , family Togaviridae [2,3].…”

Mosquitos (Diptera: Culicidae) en el caserío de Chingalé, Santander, donde se registró un caso humano de encefalitis equina venezolana

“…confinnis es considerado vector de las cepas epizoóticas (subtipo IC) y segundo en importancia después de Ae. taeniorhynchus (1). En los estudios realizados por Morales et al (27,28), a nivel experimental se logró la infección de este mosquito con el subtipo ID y luego la transmisión a ratones.…”

“…Los casos humanos de encefalitis equina venezolana son ocasionados por diferentes subtipos de una especie de virus llamada VEEV (Togaviridae: Alphavirus), la cual, conjuntamente con otras seis especies de virus, hace parte del complejo seroló-gico de la encefalitis equina venezolana (1,2).…”

“…Los subtipos enzoóticos comenzaron a aislarse en los años 50 en hábitats selváticos y pantanosos de Suramérica, México y Florida, donde sus ciclos epidemiológicos se mantienen permanentemente (1,4). A diferencia de los subtipos epizoóticos, infectan principalmente pequeños mamíferos, no están asociadas con enfermedad en équidos, pero sí con los humanos, que se pueden infectar y desarrollar la enfermedad, la cual en algunos casos puede llegar a ser fatal (6).…”