Development and growth of Sarcocystis gigantea in experimentally-infected sheep.

Immature, microscopic Sarcocystis gigantea sarcocysts were detected in experimental sheep from 1.3 to 4 months after dosing with sporocysts from cats. Mature, microscopic sarcocysts were also present at 4 months post-inoculation (p.i.). S. gigantea sarcocysts were 0.35 mm long at 8.5 months p.i. and gradually increased in size to 7.5 mm by 45 months p.i. Transmission back to cats was demonstrated at 14 months p.i.