Ala. Code § 22-12-21

During the existence of quarantine, state or local, the supervision of trains, buses, aircraft and watercraft affected by such quarantine shall be placed under the State Board of Health; and the quarantine authorities of any county, incorporated city, or town traversed by such roads or which such aircraft or watercraft may enter may decline to receive freight, mail or express matter from a place infected with a quarantinable disease, of which refusal the said authorities must give the State Health Officer immediate notice.