No, if she's been treated properly, the protozoa should be cleared from her system. No relapse, no infecting the fetus. Post-treatment symptoms are the result of extant CNS damage, not ongoing infection.

Also, the placenta is *usually* a barrier to infection; even if the mare had an active infection in the early stages when the protozoa is multiplying in the blood vessels before migrating to the central nervous system, it may not be possible for the fetus to become infected - totally dependent on the specific organism and I'm not up on the physiology of equine placentas and s. neurona . If the infection had moved out of the bloodstream and into the CNS, it would be even less likely.

She will test positive for *antibodies* to EPM, as will any horse exposed to the organism. Testing for the actual organism is much harder (requires an uncontaminated spinal tap) and is usually not done.

If the mare has recovered to a point of being physically able to manage the weight/ balance changes of pregnancy, there is no reason (related to EPM) not to breed her.