58 Pa. Code § 183.125
If an eligibility or validation certificate has been issued and it is determined thereafter that the horse for which the certificate has been issued has equine infectious anemia or is a carrier thereof, the certificate must be returned immediately by the holder to the United States Trotting Association and the horse must vacate the premises as required under the provisions of § 183.37 (relating to requirements for admission of horses to Pennsylvania Pari-Mutuel Racing Association plants).
This section cited in 58 Pa. Code § 181.1 (relating to definitions).