Failure of combination therapy with imidocarb dipropionate and toltrazuril to clear Hepatozoon canis infection in dogs

Abstract

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.

First report of Babesia gibsoni in Central America and survey for vector-borne infections in dogs from Nicaragua

“…Many dogs have concurrent infections with vector-borne agents such as E. canis and Babesia spp., and deciding each agent’s contribution to signs is difficult. Various treatments have been used but none are fully effective [34]. …”

An Australian dog diagnosed with an exotic tick-borne infection: should Australia still be considered free from Hepatozoon canis?

“…Imidocarb dipropionate (5-6 mg/kg every 14 days) is used to treat canine hepatozoonosis (Baneth and Weigler, 1997), but the therapeutic efficacy is inconsistent and will not necessarily result in a parasitological cure (Ogunkoya et al, 1981;Sasanelli et al, 2010;De Tommasi et al, 2014). Similarly, the efficacy of toltrazuril is inconsistent (Krampitz and Haberkorn, 1988;Macintire et al, 1997;Tort et al, 2007) and results from studies on combination therapies with emodepside/toltrazuril (Procox® suspension for dogs (Altreuther et al, 2011)) and clindamycin (De Tommasi et al, 2014), and imidocarb dipropionate/toltrazuril (Pasa et al, 2011) showed no statistically significant difference in clinical efficacy compared with monotherapies. However, Pasa et al (2011) reported a better overall clinical response with imidocarb dipropionate/toltrazuril compared with imidocarb dipropionate treatment alone (Pasa et al, 2011).…”

Brazilian canine hepatozoonosis

“…The drug of choice has long been ID, although the treatment results from this drug have been inconsistent (PASA et al, 2011).…”

“…Recently, Pasa et al (2011) tried to improve the efficacy of H. canis treatment with an association of ID (at a dose of 6 mg.kg -1 subcutaneously twice, 14 days apart) with oral toltrazuril (at 10 mg.kg -1 once daily for the first five treatment days). The overall clinical efficacy of ID with and without toltrazuril was 83.3% and 66.7%, respectively, and the authors concluded that toltrazuril did not produce any additional benefit for ID therapy.…”