The commissioner of the department of health and human services or designee shall appoint directors of the various divisions of the department and shall determine the salary, within the limits of legislative appropriations to the department and in conformity with the state merit system, to be received by such persons. The duties of such director must be those prescribed by the commissioner of the department of health and human services or designee. The state health officer may appoint a deputy state health officer. A deputy state health officer who does not hold a health-related degree may not individually issue an order regarding public health unless the order is cosigned by a physician who is employed by the department or cosigned by the state epidemiologist. The deputy state health officer serves at the pleasure of the state health officer.