Current treatments with
imidocarb dipropionate for infected dogs with Hepatozoon canis do not always provide parasitological cure. The objective of this study is to determine whether concomitant use of
toltrazuril may potentiate the effect of
imidocarb dipropionate in the management of H. canis
infection (HCI). Twelve dogs were determined to have naturally HCI based on clinical signs, identification of the parasite in blood smears, and serologic assay. The animals were allocated randomly to one of two groups (n = 6 in each group). Dogs in Imi group were given
imidocarb dipropionate at a dose of 6 mg/kg
body weight subcutaneously in two
injections 14 days apart. Imi plus Toltra group was given
imidocarb dipropionate as dose mentioned above and
toltrazuril at 10 mg/kg/day orally for the first five treatment days. Clinical findings, blood counts and parasitaemia levels in blood before and 14, 28 and 56 days after the initial treatment were performed to evaluate treatment response. The overall clinical efficacy of
imidocarb dipropionate with and without
toltrazuril was 83.3% and 66.7%, respectively; with a mean recovery time of 21.0 and 25.6 days, respectively. A substantial main effect of time on mean PCV, Hb, WBC, neutrophil and PLT and gradual reduction of parasitaemia were significantly observed in both groups (P < 0.05), whereas no significant difference was noticed between the studied protocols. The parasitologic cure rate at the end of eight weekly observation period was 16.6% and 33.3% in Imi and Imi plus Toltra groups, respectively. Similar clinicopathologic and parasitologic responses were observed in both treated groups; thus, it was concluded that
toltrazuril does not reveal additional benefit to
imidocarb therapy in dogs with HCI.