Sarcocystis dubeyi n. sp. (Protozoa: Sarcocystidae) in the water buffalo (Bubalus bubalis).

Sarcocystis dubeyi n. sp. is proposed for a species forming thick-walled, microscopic sarcocysts in striated muscular tissues of the water buffalo (Bubalus bubalis). Sarcocysts of S. dubeyi were found in histological sections of skeletal muscles and esophagus, but not in heart and tongue, of 8 (13%) of 60 water buffaloes examined in Ho Chi Minh City, Vietnam. Sarcocysts of S. dubeyi were up to 600 microns long and up to 200 microns wide. The cyst wall was 4.5-9 microns thick and was composed of tightly packed, cylindrical villar protrusions (Vp) that had a uniform width of up to 3 microns, a length of up to 8 microns, and a blunt, often flattened tip. The Vp contained microfilaments but no prominent electron-dense granules. The definitive host of S. dubeyi was not determined, but it could possibly be humans or other primates. By the present description, 4 Sarcocystis species are recognized in the water buffalo: the macrocyst-forming Sarcocystis fusiformis and S. buffalonis and the microcyst-forming S. levinei and S. dubeyi.