(a) The governing body of a municipality or the commissioners court of a county that has not established a local health department or a public health district may appoint a physician as health authority to administer state and local laws relating to public health in the municipality's or county's jurisdiction.
(b) The governing body of a municipality or the commissioners court of a county described by Subsection (a) that is receiving a grant under Section 121.0065 shall appoint a physician as health authority.
(c) An individual appointed to serve as health authority for a county or municipality may serve as the health authority for one or more other jurisdictions under an interlocal contract made in accordance with Chapter 791, Government Code.