510 ILCS 95/4
All breeding swine 4 months of age and over entering Illinois for breeding or exhibition purposes shall be accompanied by an official interstate health certificate, issued by an accredited veterinarian of the state of origin, showing that such swine meet the Illinois entry requirements and are negative to an official test for brucellosis conducted by an official laboratory of the state of origin within 30 days prior to entry. However, swine from a validated brucellosis-free herd or a Validated Brucellosis-free Area may enter the State or be exhibited without a test for brucellosis when accompanied by a certificate of health issued by an accredited veterinarian of the state of origin or a veterinarian employed by the Animal and Plant Health Inspection Service of the United States Department of Agriculture or any successor agency, showing such swine to have originated from a Validated Brucellosis-free Area or validated Brucellosis-free herd and giving the validated herd certificate number and anniversary date.
510 ILCS 95/4