Successful management of immune-mediated hemolytic anemia secondary to infection with cytauxzoon felis and feline immunodeficiency virus

Cytauxzoonosis is caused by Cytauxzoon felis (C. felis) in wild and domestic cats. However, cytauxzoonosis is uncommon in Asia. Additionally, clinical reports of C. felis infection along with associated complications are rare. A seven-year-old neutered male Maine Coon cat was presented with acute dyspnea and lethargy despite the absence of a history of overseas travel. Mild regenerative anemia and autoagglutination were detected in hematological investigations. The parasitic and viral PCR assays revealed infection with C. felis and feline immunodeficiency virus (FIV). Thoracic radiographs showed pleural effusion with secondary bacterial infection. Ultimately, a diagnosis of infection-induced secondary immune-mediated hemolytic anemia (IMHA) and pyothorax was established. The cat was treated with a combination of atovaquone, prednisolone, and cyclosporine over 6 months and the final treatment was completed 8 months after initiation of therapy. This is the first report of its kind demonstrating successful management of feline IMHA and fatal pyothorax induced by FIV and C. felis in South Korea.