It shall be unlawful for any county judge in this state to be either directly or indirectly interested, in his or her own county, in:
(1) The building or repairing of any public building or the building or repairing of any public bridge;
(2) Any toll bridge or causeway;
(3) Any public ferry;
(4) The keeping, feeding, or clothing of any pauper or poor or insane person;
(5) Any real or personal property, stationery, furniture, wood, or other materials purchased for the use of the county; or
(6) Any internal improvement to be paid for, in whole or in part, by the county.