Cohn LA, Birkenheuer AJ, Brunker JD, et al. Efficacy of atovaquone and azithromycin or imidocarb dipropionate in cats with acute cytauxzoonosis. J Vet Intern Med 2011;25:55-60.
Cytauxzoonosis is an acute-onset disease of cats caused by the parasite Cytauxzoon felis, which is transmitted by the bite of a tick. The disease is historically considered a fatal infection in domestic cats, though a number of cats have been known to have survived the disease. Most affected cats are young adults with exposure to the outdoors and vague clinical signs of lethargy and anorexia. The standard therapy for cytauxzoonosis has become imidocarb diproprionate. A combination of atovaquone and azithromycin (A&A) has also been suggested as a treatment. Neither form of therapy has been prospectively evaluated for efficacy. Eighty acutely ill cats with Cytauxzoon felis infection were treated at one of 18 veterinary clinics. Of 53 cats treated with A&A, 32 (60%) survived to discharge. Only 7 of 27 cats (26%) treated with imidocarb survived. Still, mortality remained high with approximately 40% of A&A treated cats dying in the hospital. The course of illness is swift and most cats that died did so shortly after presentation for care. The authors suggest that efforts must remain focused on prevention of disease, either through minimization of exposure to tick vectors or through development of chemoprophylaxis or vaccination. [VT]