The jurisdiction of an established county department of health in the county or counties which have established it shall extend to all townships of the second class, to all municipalities which do not have departments or boards of health at the time of the establishment of the county department of health, to all municipalities or parts of municipalities in which the local administration of health laws at the time of the establishment of the county department of health is being performed by the State Department of Health for any reason whatsoever, to all municipalities which dissolve their departments or boards of health in accordance with section 15 of this act,¹ and to certain parts of municipalities as provided in sections 15 and 16 of this act.²