Crystalline inclusions in Leucocytozoon simondi

Abstract

Vacuoles have been observed in haemosporidian ookinetes fixed in methanol and stained with Giemsa's (5) (Fig. 1). Electron microscopy studies on sporogony of Leucocytozoon simondi indicate that the "vacuoles" contain accumulations of crystalline material (8) (Fig. 3). This material is observed in the ookinete and later aggregates into a central core in the early oocyst. As the sporozoite buds form around the peripheral cytoplasm, the central core breaks up and crystalline material passes into each forming sporozoite. A reserve energy source was postulated as a possible function for the material (6, 8). Recently a similar crystalline inclusion found in ookinetes and early oocysts of related Plasmodium species (9) has been incriminated as a virus on strictly morphological grounds (14). A histochemical study was undertaken to clarify the nature and composition of this material in L. simondi.