Muscular Sarcocystis infection in a bear (Ursus americanus).

Sarcocysts of an unidentified Sarcocystis species were found in sections of skeletal muscles of a black bear (Ursus americanus) from North Carolina. Two sarcocysts in a section measured 45 x 37.5 microm and 67.5 x 50 microm and had a thin (<2 microm) sarcocyst wall. The villar protrusions on the cyst wall were up to 2 microm long and up to 0.7 microm wide. The bradyzoites were approximately 6 X 2.5 microm in size. This is the first report of muscular Sarcocystis in a bear.