Incidental Case of Sarcocystis in Cynomolgus Monkey

Intramuscular cysts were found spontaneously in a 3-year-old Cynomolgus monkey used for 6-week toxicity study. The animal belonged to the control group. It didn’t exhibit any morphological and behavioral defects, and have abnormal lesion at necropsy observation. In the histopathology, there were no specific lesions except that the two cysts, wrapped by thin wall, were located in the muscle fiber of femoral muscle and full of dense substances. There was no inflammatory reaction around cysts. They are considered to be sarcocystis in view of its typical morphology and location.