Efficacy of an experimental fasciolicide against immature and mature Fasciola hepatica in artificially infected calves

Abstract

The efficacy of 5-chloro-2-methylthio-6-(1-naphthyloxy)- 1H-benzimidazole, called "alpha", was tested against Fasciola hepatica. Fluke-free calves ( n=32) were divided into 8 groups and infected with 150 metacercariae per animal. All animals subsequently received a second infection with another 150 metacercariae, given at different time intervals aimed to produce flukes of differing ages within the experimental animals. When the flukes reached the required age in the animals, four groups were treated with a single oral dose of 12 mg/kg of compound alpha and the remaining ones served as non-treated controls. Two weeks after treatment the animals of all groups were sacrificed and the livers were removed to determine the numbers of parasites present in the treated and untreated controls. In the treated groups the fluke reduction for the 3 day/2 week group was 100%, for the 3 week/4 week group it was 96.4%, for the 6 week/8 week group it was 99.2% and for the 10 week/12 week group it was 100%.

Immature triclabendazole-resistant Fasciola hepatica: tegumental responses to in vitro treatment with the sulphoxide metabolite of the experimental fasciolicide compound alpha

“…SO is capable of exerting an effect on the juvenile TCBZresistant F. hepatica. It is uncertain whether this is significant enough to yield an efficacy similar to those reported against a presumably TCBZ-susceptible Mexican isolate (Hernández-Campos et al 2002;Ibarra et al 2004;Vera Montenegro et al 2004). An in vivo study involving Fig.…”

“…In in vivo treatments involving sheep, the activity against all stages of the parasite was found to be between 86.9 and 100% using a dose of 15 mg/kg (Ibarra et al 1997a(Ibarra et al ,b, 1999Rivera et al 2002). With infected cattle, compound alpha (at 12 mg/kg) displayed an efficacy of 98.1-100% against all stages of the fluke (Vera Montenegro et al 2003Montenegro et al , 2004). An in vitro study using the Sligo TCBZresistant isolate showed that compound alpha is capable of disrupting the tegument and associated tegumental cells of mature flukes following 24 h of incubation with the sulphoxide metabolite of compound alpha (McConville et al 2006).…”

Morphological response of triclabendazole-susceptible and triclabendazole-resistant isolates of Fasciola hepatica to treatment in vitro with nitroxynil (Trodax)

“…In order to maintain control of fascioliasis, it is necessary to develop new drugs or make-do with existing drugs. With regard to new drugs, a derivative of TCBZ known as compound alpha has been developed (Hernández-Campos et al 2002;Vera Montenegro et al 2004;McConville et al 2008). Much interest has been shown in artemisinin-type compounds, which have been used as antimalarials and are active against schistosomes (Caffrey 2007;Keiser and Utzinger 2007a;Utzinger et al 2007).…”

Paramphistomicidal efficacy of an experimental compound in sheep

“…Considering the fasciolicidal efficacy previously shown by the compound 5-chloro-2-(methylthio)-6-(1-naphthyloxy)-1H-benzimidazole, known as compound alpha , in sheep and cattle, (Ibarra et al 1997(Ibarra et al , 2000Vera et al 2001Vera et al , 2003Vera et al , 2004Rivera et al 2002Rivera et al , 2004Rivera et al , 2005, it was deemed relevant to modify its chemical structure and synthesize alpha-carbamate aimed at testing this new compound at the intestinal level against paramphistomids in sheep.…”