Fungi which don't often cause infections in people with healthy immune systems but can under some circumstances, and can be tremendous problems in patients that have weakened immune systems.

真菌在免疫系统健康的情况下通常,不引起感染,但在某些情况下也会感染,那就成了极大的问题,在免疫系统脆弱的病人体内

耶鲁公开课 - 生物医学工程探索课程节选