(a) Except as provided in subsection (b) of this section, the department shall provide or designate adequate facilities for the free diagnosis, including blood and other tests, of venereal disease and for the free treatment of persons infected with venereal disease when necessary for the preservation of the public health.

(b) Upon approval of the department, any local board or department of health may undertake to share the expense of furnishing free diagnosis and free treatment of venereal disease, or the local board or department of health may take over, entirely or in part, the furnishing of free diagnosis and free treatment of venereal disease with or without financial assistance from the department.