untreated

Drinking untreated water from a stream can lead to severe stomach infections caused by parasites.

(Chinese) 饮用溪流中未经处理的水可能会导致由寄生虫引起的严重胃部感染。

If a deep cat scratch is left untreated, it can quickly become infected and cause a fever.

(Chinese) 如果猫抓的深伤口不处理，很快就会被感染并引起发烧。