translation.en: And this is the reason: in two countries that hadn't had this disease for more than probably a decade, on opposite sides of the globe, there was suddenly terrible polio outbreaks.
translation.zh: 原因如下 有两个国家 十多年未出现脊髓灰质炎 它们各位于地球两端 却突然都爆发了严重的脊髓灰质炎