目的 分析2014年发生在西非地区的埃博拉病毒病(Ebola virus disease, EVD)疫情流行特征,为制定中国防控策略和措施提供科学依据.方法 根据世界卫生组织公布的疫情相关资料,采用描述性流行病学方法对资料进行分析.结果 2013年12月至2014年9月13日几内亚(Guinea)、利比里亚(Liberia)、塞拉利昂(Sierra Leone)、尼日利亚(Nigeria)和塞内加尔(Senegal)5国共报告EVD病例4985例,死亡2461例,病死率为49%.截至目前疫情整体呈现为两个阶段,第一阶段为2013年12月至2014年4月,疫情主要集中在几内亚;第二阶段为2014年5-9月,疫情主要影响几内亚、利比里亚和塞拉利昂;除尼日利亚外,其余4国彼此相邻,大面积陆路接壤.尼日利亚疫情是由1名利比里亚患者输入导致的继发感染,而塞内加尔报告的是1例几内亚病例.截至2014年9月13日,5个国家中医务人员感染人数近300人(约占总病例数的6%),死亡超过140例.基因分析显示,引发此次疫情的病毒是埃博拉病毒中扎伊尔型(Zaire ebolavirus)的一个独立分支.结论 2014年发生在西非地区的EVD暴发疫情是自1976年发现埃博拉病毒(Ebola virus, EBOV)以来最大的一次暴发,同时也是西非地区首次报告EVD疫情,目前形势分析认为疫情可能仍将持续6~9个月.
Objective To understand the epidemiological characteristics of Ebola virus disease (EVD) in West Africa in 2014 and to provide scientific evidences for EVD prevention in China. Methods Descriptive epidemiological analysis was conducted on the EVD epidemic data published by World Health Organization. Results A total of 4985 EVD cases, including 2461 deaths, were reported in Guinea, Liberia, Sierra Leone, Nigeria and Senegal from December in 2013 to 13 September in 2014. The case fatality rate was 49%. Until now, 2 stages of epidemic have been observed, the first one was characterized by the outbreak in Guinea from December 2013 to April 2014; and the second one was from May to August in 2014 when the disease spread in Guinea, Liberia, and Sierra Leone. Except Nigeria, the other four countries bordered each other. The secondary transmission in Nigeria was caused by an EVD case imported from Liberian, and the secondary transmission reported by Senegal was caused by an EVD case from Guinean. As of September 13, nearly 300 health-care workers have been infected in the five countries (nearly 6% of total cases), in which more than 140 died. Genetic analysis indicates that the virus caused this outbreak is a separate clade of the Zaire ebolavirus (EBOV). Conclusion The public health emergency of Ebola virus disease (EVD) occurring in West Africa in 2014 is not only the largest outbreak since the Ebola virus was first discovered in 1976, but also the first report of EVD outbreak in West Africa. The outbreak might last for 6 to 9 months from now on.