Efficacy of a Combination of Imidacloprid plus Moxidectin against Larval and Adult Stages of Nematodes (Trichuris muris, Angiostrongylus cantonensis) in Rodents

Abstract

Two combination products of imidacloprid plus moxidectin for cats or dogs which differ in the ratio of the active components (10:1 or 10:2.5, w/v) were tested in the laboratory mice strain C57BL/10 experimentally infected with Trichuris muris. A single topical administration of 32.0 mg imidacloprid per kg body weight (bw) plus 3.2 mg moxidectin per kg bw at 20 day post infection (dpi) led to a complete elimination of mature T. muris at 52 dpi. However, when the same dose was administered at 35 dpi or 52 dpi, the survival rates were 24.4 or 38.2% at 52 or 54 dpi, respectively. Following incubation with 8.0, 16.0 or 32.0 mg imidacloprid per kg bw plus 2.0, 4.0 or 8.0 mg moxidectin per kg bw at 20 dpi, all mature T. muris were dead at 52 dpi. When single treatments at 35 dpi were done with 8.0, 16.0 and 32.0 imidacloprid per kg bw plus 0.8, 1.6 or 3.2 mg moxidectin per kg bw, the survival rates at 52 dpi were 31.4, 44.4 or 24.4%. Using 8.0, 16.0 or 32.0 mg imidacloprid per kg bw plus 2.0, 4.0 or 8.0 mg moxidectin per kg bw at 35 dpi, the survival rates were 54.5, 42.3 or 33.7%. When treatment was done against mature T. muris at 52 dpi, the combination of 128.0 mg imidacloprid per kg bw plus 12.8 mg moxidectin per kg bw led to a survival rate of 21.3%, whereas 128.0 mg imidacloprid per kg bw plus 32.0 mg moxidectin per kg bw resulted in the strongly decreased survival rate of 8.0%.