Ultrastructural studies of Sarcocystis cruzi (Hasselmann, 1926) Wenyon, 1926 infection in cattle (Bos taurus): Philippine cases

Abstract

This paper documents the first report of Sarcocysti s cruzi infection domesticated cattle (Bos taurus] in the Philippines. Fusiform-shaped microscopic sarcocysts (183-578 μm long and 20-98 μm wide) with distinct septae were found in the skeletal, striated and heart muscle. The sarcocyst wall or parasitophorous vacuolar membrane, 1.37-2.75 μm thick consisted of closely-packed villar protrusions 80-400 nm in dm. Middle and distal segments of VP were bent approximately 90 degrees parallel to the cyst wall surface. The villar core lacked microtubules, and at some points, the distal ends of the VP collectively formed conical tufts. Primary cyst wall had numerous 70-100 nm bubble-like undulations, and the ground substance was 0.25-0.5 μm in thickness. The ultrastructure of S. cruzi cyst wall typifies the Type 7 sarcocyst wall, and bears close similarities with the Philippine and the Vietnam strain of bubaline Sarcocystis levinei.