Confidently identify parasites on blood smears - Firstline
Team Center
Firstline Featuring Information from:


Confidently identify parasites on blood smears
Blood film evaluation skills a little rusty when it comes to hemoparasites? Have no fear. Read on for tips to help you prepare a readable blood smear and identify what you see.


Cytauxzoon felis


• 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.

5A-5C. Cytauxzoon felis on a blood smear. These inclusions have highly refractile centers (Wright’s stain; 5A—40x, 5B & 5C—100x).
• The inclusion will have a refractile appearance within the band portion of the ring (Figures 5A-5C).

Clinical signs

• 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.



Click here