natural nidality的用法和样例：
例句
- As one of the oldest identifiable diseases known to man, plague remains endemic in many natural loci around the world.
鼠疫作为人所共知的一种最古老可确定的疾病，在世界上许多自然疫源地仍呈地方性流行。 - Conclusion The findings of the present study imply that the natural foci of human monocytic ehrlichiosis may exist in northwestern Fujian Province.
结论福建西北部林区可能存在人单核细胞埃立克体病的自然疫源地。
