大多数结核病发生在南亚、东亚 、 非洲和西太平洋沿岸国家.

Most TB cases are in South and East Asia, Africa and West Pacific nations.

因此，汉朝人了解非洲并且有书籍描述了红海和非洲沿岸国家的情况。

Thus, people of the Han Dynasty knew about Africa and had books with description of the kingdoms on the African coast and the Red Sea.