Survey of sarcocystis spp. infection in Philippine livestock animals: light microscopic and ultrastructural studies

Sarcocystis, a coccidian apicorrplexan species,is known to infect a wide range of wild and domestic animals,including humans (Heydorn et al.,1975, Dubey et al., 1989). Except for earlier reported infection of Philippine water buffaloes (Bubalus bubalis) with Sarcocystis fusiformis (Tongson and Molina, 1979, Manuel et al.; 1983, Paraiso et al.,1988), studies on the etiologic agents of sarcocystosis in Philippine livestock animals are scanty. Using microscopy, examination of muscle tissues obtained from water bufaloes, cattle, hogs, goats, chickens, and ducks revealed the presence of sarcocysts in skeletal,diaphragm, cervical,pharyngeal, esophageal, and heart muscle.Identification of the etiologic agents was based on the ultrastructural analysis of the sarcocyst wall following the cyst wall type classification scheme (Dubey et al.,1989). The species identified are as follows: Sarcocystis cruzi (Hasselman,1926) Wenyou, 1926 homegrown cattle (Bos taurus) possessing the Type7 sarcocyst wall (Claveria et al., 2001:Parasite 8: 251-254);Sarcocystis levinei in water buffaloes (Bubalus bubalis) possessing a Type 7 sarcocyst wall (Claveria and Cruz, 2000:Parasitology International, 48: 243-247) with similarities of S.cruzi; Sarcocystis miescheriana (Kuhn,1865) Labbe,1899 (syn: Sarcocystis suicanis Erber,1977) in domestic pigs (Sus scrofa) with Type10 sarcocyst wall (Claveria et al., 2001:J.Parasitology, 87: 928-939), and Sarcocystis capracanis in domestic goats (Capra hircus) with Type 14 sarcocyst wall (Claveria et al., 2004:Philippine J Science,133:33-37).Muscle tissues of chickens showed large fusiform shaped immature sarcocystis with underdeveloped sarcocyst wall and manifested marked damage to surrounding host tissues and muscle cell/fiber and myofibrils, suggestive of the pathogenic nature of this species. While the sarcocystis exhibited striated primary cysts wall with stubby looking villar protrusions,species could not be ascertained owing to the difficulty in interpretation of microtubular arrangement. The sarcocystis spp. infection reported here in represent the first documented Philippine studies in cattle, water buffaloes, hogs, goats, and chicken.