An equine in isolation pursuant to sections 22-415e and 22-415f shall be confined to an enclosure or pasture whose boundaries are not less than two hundred yards from an enclosure or pasture harboring an equine which has not had an official equine infectious anemia test or is found to be negative to such test, provided the commissioner may approve confinement to an enclosure or pasture whose boundaries are less than two hundred yards upon determination that such enclosure or pasture is sufficiently screened to preclude entry of biting insects. No reactor may be moved from an isolation area except upon written authorization by the State Veterinarian.