Two types of ovine Sarcocystis macrocysts distinguished by periodic acid-Schiff staining of the cyst walls

Abstract

Periodic acid-Schiff (PAS) applied to histological sections of ovinemuscles, infected naturally with sarcocysts, showed that only macroscopic “fat” Sarcocystis tenella had PAS-positive secondary cyst-walls after fixation only. Macroscopic “thin” S. medusiformis and microscopic S. ovicanis sarcocysts had cyst-walls that were not positive despite fixation.