The commissioner of the Bureau for Public Health is the state health officer and shall be appointed by the secretary. The commissioner shall be a physician licensed under the laws of this state to practice medicine or a person holding a doctorate degree in public health administration. The commissioner shall have not less than four years' experience in health services administration or a related field. The commissioner serves at the will and pleasure of the secretary and shall not be actively engaged or employed in any other business, vocation or employment, serving full time in the duties of the office as prescribed by this article.