Sarcocystis miescheriana infection in domestic pigs (Sus scrofa) in the Philippines

Sarcocystis miescheriana sarcocysts were identified in skeletal muscles of 9 (27%) of 33 swine slaughtered for human consumption. Sarcocysts were 144–180 μm × 20–38 μm in size. Ultrastructurally, the cyst wall resembled the type 10 sarcocyst wall. The villar protrusions (VP) were 3–4.5 μm long and 0.6–1.2 μm wide and had prominent longitudinally arranged microtubules extending from the VP tips to the granular layer (=ground substance). The parasitophorous vacuolar membrane with its underlying electron-dense layer (EDL) measured 25 nm in thickness. The base of the VP exhibited minute (0.42–0.87 μm) bulblike inpocketings. Each VP had 80–90 microtubules situated underneath the EDL. The granular layer was 0.5–1.2 μm thick, and contained hairlike microtubules continuous with those of the VP core. This is the first report of S. miescheriana in Philippine domestic pigs Sus scrofa.