N-UNCOUNT 慢性疲劳综合征(常使用缩略形式 CFS) Chronic fatigue syndrome is an illness that is thought to be caused by a virus, and which affects people for a long period of time. Its symptoms include tiredness and aching muscles. The abbreviation CFS is often used. 慢性疲劳综合征(常使用缩略形式 CFS)