Cytauxzoonosis is an extraordinarily rapid illness that often causes death in otherwise healthy cats. The disease is caused by the hemoprotozoan parasite Cytauxzoon felis, and is transmitted to cats by the bite of a tick. Once considered a rare and geographically restricted disease, the illness is an emerging disease with an expanding geographic range, having been recognized in 20 of the 48 continental United States. Without treatment, approximately 95% of sick cats will die within 5 days of the first signs of illness.
Recently, a combination of an antimalarial drug (atovaquone) and an antibiotic (azithromycin) plus supportive care has been demonstrated to result in a 60% survival rate. Unfortunately, atovaquone doesn’t work on all strains, is expensive, difficult to obtain, and difficult to administer. An alternative antimalarial drug, Coartem®, is far less expensive and can be given as a tablet twice daily for three days. Survival rates in the few cats treated so far with this potential alternative have been encouraging.
We propose to compare the efficacy of these two treatment regimens for cytauxzoonosis in naturally infected cats. If survival is similar for the two, Coartem would offer tremendous benefit in terms of cost, ease of administration, and availability as compared to atovaquone and azithromycin. Additionally, it may work on strains of the pathogen not susceptible to atovaquone.