Efficacy of the compound preparation imidacloprid 10% / permethrin 50% spot-on against ticks (I. ricinus, R. sanguineus) and fleas (Ct. felis) on dogs

The objective of this study was the evaluation of the acaricidal efficacy of Imidacloprid 8.8% w/w and Permethrin 44% w/w spot-on against ticks (Ixodes ricinus, Rhipicephalus sanguineus) and its adulticidal and larvicidal/development inhibiting efficacy against fleas (Ctenocephalides felis) on dogs. A total of forty dogs were allocated to two treatment and two untreated control groups of ten animals each. On day 0 ten tick and ten flea infested dogs received 0.1 ml/kg bodyweight of the test compound a combination of Imidacloprid 8.8%/Permethrin 44% dermal spot-on solution, the other two groups served as untreated controls. Dogs were reinfested weekly with 100 fleas or 50 adult Rhipicephalus + 50 adult Ixodes ticks (sex ratio: 1:1), respectively for a period of five weeks. Flea counts were conducted at 24 and tick counts at 48 hours post treatment/reinfestation.. The flea larvicidal efficacy in the dog’s surroundings was evaluated by a blanket sample incubation method. The efficacy against Rhipicephalus sanguineus was 74.0% (day 2), 94.0% (day 9), 97.6% (day 16), 92.0% (day 23), 95.9% (day 30) and 91.5% (day 37), against Ixodes ricinus was 67.0% (day 2), 100.0% (day 9), 100.0% (day 16), 99.5% (day 23), 98.7% (day 30) and 91.6% (day 37). The adulticidal flea efficacy was 99.4% (day 1), 99.8% (day 8), 99.9% (day 15), 98.8% (day 22), 95.7% (day 29) and 90.4% (day 36). The larvicidal efficacy after 12 hours blanket contact was 99.2% (day +3), 98.2% (day +10), 98.5% (day +17), 85.1% (day +24) and 50.2% (day +30). The combination of imidacloprid and permethrin eliminated the existing flea infestation and prevented the dogs from flea and tick infestation for four weeks.