Which clinical sign would prompt inclusion of equine babesiosis (piroplasmosis) in your differential diagnosis?

• A. Anemia
• B. Hives
• C. Lameness
• D. Profuse nasal discharge

Answer: (A)

Equine babesiosis causes red blood cell destruction by parasites that replicate inside RBCs, leading to hemolytic anemia. The most consistent sign you’d expect from this process is anemia, often with pale mucous membranes and fatigue, and sometimes fever or icterus. Because the parasite directly targets erythrocytes, noticing anemia should prompt including babesiosis in your differential, especially if there’s tick exposure or travel to endemic areas. The other signs listed—hives, lameness, or profuse nasal discharge—don’t fit the typical disease pattern as well, since they point toward non-hemolytic or non-cardiopulmonary processes rather than an RBC-destructive infection.