The nature of bands in parasitized bovine erythrocytes.

Anaplasma marginale is the etiological agent of a hemolytic disease of cattle, known as anaplasmosis. The organism appears as a marginal inclusion in parasitized erythrocytes, but certain isolates also have bands associated with the inclusion. Inclusions and associated bands in parasitized erythrocytes in the liver and peripheral circulation were studied by light microscope cytochemistry and electron microscopy. Bands were comet- and dumbbell-shaped by light microscopy and were stained by techniques used to demonstrate protein and fibrin. The same forms, as well as other shapes, were seen in infected erythrocytes which were sectioned and examined by electron microscopy. Bands had longitudinal and transverse periodicity. They did not appear to have a crystalline structure. Their appearance was collated with that of bovine fibrin. Bands were well differentiated in erythrocytes that were entensively hemolyzed by natural or artificial means, but poorly differentiated in mildly hemolyzed erythrocytes. Hemolysis methods appeared to influence the morphology of bands and their demonstration.