Efficacy of Ivermectin in a Beef-Based Chewable Formulation against Ancylostoma caninum and Uncinaria stenocephala in Dogs

Abstract

The effective dosage of a chewable formulation of ivermectin was determined in 35 young dogs with induced infections of Ancylostoma caninum and Uncinaria stenocephala. Dogs were inoculated with these parasites and held until the infections were patent. Within each of 7 replicates, dogs were allocated randomly to 1 of 5 treatment groups: vehicle control, or ivermectin at 6, 12, 18, or 24 micrograms/kg. Chewable treatments were tailored to body weight. Seven or 8 days after treatment, parasites were recovered using standard techniques. All 7 controls had adult A. caninum (geometric mean = 35.5) and U. stenocephala (geometric mean = 82.6). Against A. caninum, the efficacy of ivermectin was 52%, 98%, 95%, and 97% at 6, 12, 18, and 24 micrograms/kg, respectively. The statistical model that best described the dose response was linear to 12 micrograms/kg with a plateau thereafter. Using this model, the estimated reduction from the predicted control mean was 97.2%; the estimated dose to eliminate 90% of the worms (ED90) was 8.4 micrograms/kg, and the ED95 was 10.5 micrograms/kg. Against U. stenocephala, the dose response was linear in the range studied, with an ED90 of 20.8 micrograms/kg; it was estimated that 93.2% of the worms would be eliminated.

Comparative efficacy of ivermectin and fenbendazole against ancylostomiasis in dogs

“…Chhabra et al (2001) reported complete elimination of Ancylostoma caninum in dogs treated with single dose of ivermectin at 200 µg/kg body weight one week after its administration. Daurio et al (1993) reported the e cacy of chewable formulation of ivermectin to be 52%, 98%, 95% and 97% at 6, 12, 18 and 24 µg/kg body weights respectively in 35 young dogs with induced infections of A. caninum and U. stenocephala .…”

Pharmacological approaches towards rationalizing the use of endoparasitic drugs in small animals

“…At this dose IVM has a relatively narrow spectrum of activity, and is less effective against other GI nematodes. For example, efficacy is only 52% against A. caninum , although this can be improved to 98% by doubling the dose (Daurio et al. , 1993).…”

“…At this dose IVM has a relatively narrow spectrum of activity, and is less effective against other GI nematodes. For example, efficacy is only 52% against A. caninum, although this can be improved to 98% by doubling the dose (Daurio et al, 1993). A chewable tablet formulation containing a combination of IVM (at 6 lg/kg) and PRT (at 5 mg/kg) has been shown to have high efficacy against T. canis (90%) and >98% efficacy against T. leonina, A. caninum and Uncinaria stenocephala (Clark et al, 1992).…”