Except as otherwise provided by law, the mayor and council of each incorporated town or city, whether incorporated under general statutes or special charter in this state, may establish a municipal public health agency and appoint a municipal board of health. If appointed, the municipal board of health shall have all the powers and responsibilities and perform all the duties of a county or district board of health as provided in this part 5 within the limits of the respective city or town of which they are the officers.