It shall be unlawful for school authorities to employ teachers, janitors, food handlers or bus drivers who have tuberculosis in an infectious stage. Every board of education shall require a physical examination for tuberculosis, including adequate laboratory tests and X rays, of all such employees of the board at least once in three years. Such examinations, tests and X rays shall be made by the several county health departments; or an employee may be examined at his own expense by any other duly licensed doctor of medicine who is a specialist in the treatment of the disease of tuberculosis of his own choosing. If the result of such examination indicates the presence of tuberculosis in an infectious stage, the employee shall be ineligible for further service until satisfactory proof of recovery is furnished. It shall be unlawful for any school official to employ this section as a means of discharging any teacher or other employee for any reason other than failure to comply with the provisions of this section; and, upon proof thereof, the same shall constitute malfeasance in office and shall be grounds for his removal therefrom.