Toxoplasma gondii-like schizonts in the tracheal epithelium of a cat.

Toxoplasma gondii-like schizonts were found in tracheal epithelium of an 8-yr-old male cat. The parasites were located in parasitophorous vacuoles within the host cell cytoplasm, divided by schizogony, contained periodic acid-Schiff-positive granules, and reacted with anti-T. gondii serum but not with anti-Neospora caninum serum. Mature schizonts were 7.0 x 5.9 microns (5-10 x 4-10 microns; n = 22) and contained 4-16 merozoites. The merozoites were approximately 5 x 1 microns.