Diminazene diaceturate clears chronic Cytauxzoon infection in cats

Abstract

BACKGROUND: Cytauxzoon felis is a hemoprotozoal parasite that causes substantial morbidity and mortality during the acute phase of infection in cats. However, cats that survive the acute illness remain persistently infected and may serve as a reservoir for the tick-transmitted pathogen. OBJECTIVE: We investigated the ability of the antiprotozoal compound diminazene diaceturate to eliminate the pathogen from naturally infected C. felis carriers. ANIMALS: Seven healthy, chronically infected domestic cats housed in a research setting. METHODS: Prospective clinical trial. Cats were treated in a masked fashion with diminazene diaceturate (3 mg/kg) or placebo IM in a series of 2 injections 7 days apart. Clearance of the organism was assessed by light microscopy and real-time polymerase chain reaction (PCR) at 0, 3, 6, and 10 weeks. In addition, cats were monitored for behavioral changes or for changes on physical examination, CBC, plasma biochemical profile, and urinalysis periodically. Cats that remained parasitemic at the end of 10 weeks were switched to the alternative treatment and similarly monitored for an additional 10 weeks. RESULTS: Adverse events associated with treatment were limited to self-resolving hypersalivation and injection site soreness; the former was ameliorated by premedication with atropine. Parasite burden, as assayed by both light microscopy and real-time PCR, was similar between diminazene- and placebo-treated cats. CONCLUSIONS AND CLINICAL RELEVANCE: Diminazene diaceturate was unable to eliminate the pathogen or decrease parasite burden in healthy, chronically infected cats.