Navarro Juan-Carlos, Medina Gladys, Vasquez Clovis, Coffey Lark L, Wang Eryu, Suárez Alexander, Biord Hernán, Salas Marlene, Weaver Scott C
Universidad Central de Venezuela, Caracas, Venezuela.
Emerg Infect Dis. 2005 Dec;11(12):1907-15. doi: 10.3201/eid1112.050533.
Five years after the apparent end of the major 1995 Venezuelan equine encephalitis (VEE) epizootic/epidemic, focal outbreaks of equine encephalitis occurred in Carabobo and Barinas States of western Venezuela. Virus isolates from horses in each location were nearly identical in sequence to 1995 isolates, which suggests natural persistence of subtype IC VEE virus (VEEV) strains in a genetically stable mode. Serologic evidence indicated that additional outbreaks occurred in Barinas State in 2003. Field studies identified known Culex (Melanoconion) spp. vectors and reservoir hosts of enzootic VEEV but a dearth of typical epidemic vectors. Cattle serosurveys indicated the recent circulation of enzootic VEEV strains, and possibly of epizootic strains. Persistence of VEEV subtype IC strains and infection of horses at the end of the rainy season suggest the possibility of an alternative, cryptic transmission cycle involving survival through the dry season of infected vectors or persistently infected vertebrates.
在1995年委内瑞拉马脑炎（VEE）大规模动物疫情/流行病明显结束五年后，委内瑞拉西部的卡拉沃沃州和巴里纳斯州发生了马脑炎局部疫情。从每个地点的马匹中分离出的病毒在序列上与1995年分离出的病毒几乎相同，这表明IC亚型VEE病毒（VEEV）毒株以基因稳定的方式自然持续存在。血清学证据表明，2003年巴里纳斯州还发生了其他疫情。实地研究确定了地方性VEEV的已知库蚊（Melanoconion）属媒介和储存宿主，但缺乏典型的流行媒介。牛血清学调查表明，地方性VEEV毒株近期有传播，可能还有动物毒株传播。VEEV IC亚型毒株的持续存在以及雨季结束时马匹的感染表明，可能存在另一种隐秘的传播循环，即通过感染的媒介或持续感染的脊椎动物在旱季存活下来。
