If the physicians (who are competent) confirm that a particular disease is contagious (by Allah’s permission) , then it is a must for the guardians of the sick person to quarantine him in a suitable place in their home and other people should not mix with him due to the saying of the Prophet (salallāhu ‘alaihi wasallam):
لاَ ضَرَرَ وَلاَ ضِرَارَ
“There should be neither harming [of other people] nor reciprocating harm.” This is a hasan hadīth reported by Ibn Mājah (no. 2341).
See, Al-Jāmi’ fī Fiqhil-‘Allāmah Ibn Bāz (p. 1179).
Such a person should pray all his prayers in full at home including Jumu’ah, except that he prays 4 rak’ahs Dhuhr at home instead of Jumu’ah. If his sickness is hard upon him, he can combine Dhuhr with ‘Asr (at either prayer time), and Maghrib with ‘Ishā (at either prayer time), and Fajr at its time.
 There is no such thing as an infectious or contagious disease except by Allah’s permission and no disease afflicts a person or passes from person to person by itself. It is Allah who decrees it to occur.