Ultrastructure of Sarcocystis Sporocysts from Passerine Birds and Opossums: Comments on Classification of the Genus Isospora

Authors

Edith D. Box, University of Texas Medical Branch
Alan A. Marchiondo, Brigham Young University
Donald W. Duszynski, University of New MexicoFollow
C. Patrick Davis, University of Texas Medical Branch

Date of this Version

2-1980

Comments

Published in the Journal of Parasitology (February 1980) 66(1): 68-74. Copyright 1980, the American Society of Parasitologists. Used by permission.

Abstract

Sporocysts were obtained from the feces of opossums (Didelphis virginiana) which had been fed muscles of passerine birds (Molothrus ater and Cassidix mexicanus) infected with Sarcocystis. Sporocysts were examined by phase microscopy and scanning and transmission electron microscopy. Ridges on the surface of the sporocysts outlined four plates. Thin sections of the sporocyst wall showed thickened regions and gaps interpreted as cross sections of the ridges. The sporocyst wall has four major layers with a thick, granular inner layer which resembles the inner layer of sporocysts of related species. Excystation structures are discussed as a basis for classifying disporocystic coccidia to correlate with Frenkel's (1977) life cycle classification of this group.