(a) An individual shall be deemed disabled on any day in which, because of his or her physical or mental condition, he or she is unable to perform his or her regular or customary work.
(b) For purposes of this section, “disability” or “disabled” includes:
(1) Illness or injury, whether physical or mental, including any illness or injury resulting from pregnancy, childbirth, or related medical condition.
(2) Inability to work because of a written order from a state or local health officer to an individual infected with, or suspected of being infected with, a communicable disease.
(3) Acute alcoholism being medically treated or, to the extent specified in Section 2626.1, resident status in an alcoholic recovery home.
(4) Acute drug-induced illness being medically treated or, to the extent specified in Section 2626.2, resident status in a drug-free residential facility.