The schizonts of Cytauxzoon develop within macrophages while Theileria and Gonderia have their leukocytic stage in lymphocytes. Domestic cats with C.felisinfection usually present with a hemolytic crisis. An antemortem diagnosis was made in this case by demonstrating piroplasms in erythrocytes of Giemsa and Wright's stained blood smears. The domestic cat is considered to be a dead-end host due to the rapidly fatal course of the disease. Clinically, cats are depressed, anoretic, pyrexic, dehydrated, pale and jaundiced.
Death commonly occurs within a few days of onset of clinical signs.
Gross lesions include splenomegaly, enlarged edematous mesenteric lymph nodes often with petechia, ecchymotic hemorrhages in the lung and other viscera, and distended abdominal vessels. Microscopically, the presence of prominent, large schizont-containing phagocytic cells within and often occluding the lumens of vessels in the lung and spleen is considered pathognomonic. Differential diagnosis for this phase should include Haemobartonella felis, Babesia felis, Howell-Jolly bodies, or stain precipitate. The leukocytic or tissue phase must be distinguished from Toxoplasma, Leishmania, and Histoplasma. Organisms are best seen in Wright's or Giemsa-stained thin blood smears or impression smears of the spleen.