“隔离”可以用quarantine[ˈkwɒrəntiːn]
If you've taken a train or flight recently, you'd better check it out to see whether you need to quarantine yourself.
如果你近期坐过火车或飞机，最好检查一下看是否需要自我隔离。
②
更为口语化的用词是isolate[ˈaɪsəleɪt]
和其名词形式isolation [ˌaɪsəˈleɪʃn]
isolate oneself = 自我隔离
stay in isolation = 保持隔离状态
A high wall isolated the house from the rest of the village.
一堵高墙将这栋房子与村庄的其他部分隔离开来。
另外，“居家医学观察”则可以说：
medical observation at home