• This tick-transmitted intracellular protozoan affects cats.
• Cytauxzoon felis is typically seen during the spring and summer.
• The piroplasms are found within erythrocytes, commonly at the feathered edge of the smear.
• The inclusions appear as signet rings, comma-shaped, or elongated signet forms (safety pin). Multiple inclusions may be
present within the erythrocyte.
• The inclusion will have a refractile appearance within the band portion of the ring (Figures 5A-5C).
5A-5C. Cytauxzoon felis on a blood smear. These inclusions have highly refractile centers (Wright’s stain; 5A—40x, 5B & 5C—100x).
• Signs of cytauxzoonosis are related to the disease stage. Unfortunately, this disease progresses within two or three days
and is often fatal.
• Everything from lethargy, anorexia, dyspnea, icterus, and pale mucous membranes to high fever is consistent with infection
with this blood parasite.
• Quick intervention is necessary for any chance of recovery.
• Supportive treatment should be given as appropriate.
• To target the infection, cats should be given imidocarb (2 to 3 mg/kg intramuscularly) once a week for two weeks or a combination
of atovaquone (15 mg/kg orally three times a day) and azithromycin (10 mg/kg orally once a day) for 10 days.