今年早些时候在刚果民主共和国爆发的埃博拉疫情已达到一个严峻的新里程碑，病例出现在非洲大陆的第三个地区，成为迄今为止扩散范围最广的埃博拉疫情。
The Ebola epidemic that began in the DRC earlier this year has achieved a grim new milestone, turning up in a third region of the African continent, the widest footprint of any Ebola outbreak to date.
卫生官员正紧急寻找尼日利亚新发现病例的源头，这是该西非国家发现的首例病例。
Health officials are urgently seeking answers about the origins of a case newly identified in Nigeria, the first in that West African nation.