Abstract
Sarcocystis mihoensis n. sp., a heteroxenous coccidium was detected from sheep in Japan and dogs were experimentally determined as the definitive host. The cysts were 1,300-2,100 × 200-300 μm in size and had the thick cyst wall which was 10 to 12 μm thick and provided with radial striated and finger-like villar protrusions. Two 6-month old dogs fed with the cysts passed sporocysts, 15-16 × 8-9 μm in size, in the feces from day 11 to days 57-60 after ingestion. No domestic cats fed with the same cysts shed sporocysts throughout the experimental period.