Ikegami Tetsuro, Makino Shinji
Department of Microbiology and Immunology, University of Texas Medical Branch, Medical Research Building, 301 University Blvd., Galveston, Texas 77555-1019, USA.
Uirusu. 2004 Dec;54(2):229-35. doi: 10.2222/jsv.54.229.
Rift Valley fever virus (RVFV) causes massive mosquito-borne epidemics among humans and decimates ruminants in which the mortality rate is about 1% and 10-30%, respectively. Morbidity in RVFV-infected humans is high largely due to the effects of hemorrhagic fever and encephalitis. This virus is native to sub-Saharan Africa; yet if this virus is introduced into the environment, virus transmission appears to occur whenever sheep and cattle are present with abundant mosquito populations. RVFV is a negative-strand RNA virus which belongs to the family Bunyaviridae, genus Phlebovirus, and contains tripartite-segmented genomes (S, M, and L). S-segment is the ambisense genome, where N and NSs genes are coded in an antiviral-sense and viral sense S-segment, respectively. The inhibition of host mRNA synthesis, which is induced by the binding of NSs protein to RNA polymerase II transcription factor TFIIH, is the primary reason for the host-protein shut-off in RVFV-infected cells. Development of a RVFV reverse genetics system, which has not been accomplished yet, is important for the study of viral replication mechanisms, host virus interaction, viral pathogenicity as well as vaccine evaluation and development.
裂谷热病毒（RVFV）在人类中引发大规模蚊媒传播的流行病，并导致反刍动物大量死亡，其死亡率分别约为1%和10%-30%。RVFV感染人类后的发病率很高，主要是由于出血热和脑炎的影响。这种病毒原产于撒哈拉以南非洲；然而，如果这种病毒被引入环境中，只要有大量蚊子种群存在且有绵羊和牛，病毒传播似乎就会发生。RVFV是一种负链RNA病毒，属于布尼亚病毒科白蛉病毒属，含有三段式基因组（S、M和L）。S片段是双义基因组，其中N基因和NSs基因分别在反义S片段和正义S片段中编码。NSs蛋白与RNA聚合酶II转录因子TFIIH结合诱导宿主mRNA合成受到抑制，这是RVFV感染细胞中宿主蛋白关闭的主要原因。尚未完成的RVFV反向遗传学系统的开发，对于研究病毒复制机制、宿主与病毒相互作用、病毒致病性以及疫苗评估和开发具有重要意义。
