Explorers traced the Nile River to its several headstreams in Central Africa.

探险者在中非找到了尼罗河的几处源头。

Uganda: a country of east-central Africa.

乌干达：非洲中东部的一个国家。

Zambia: a country of south-central Africa.

赞比亚：非洲中南部一国家。

Now, rates are highest in west and central Africa.

现在是西非和中非最多。

Yellow fever is endemic to parts of central Africa.

黄热病是中非一些地区的地方流行病。