Efficacy of permethrin, dinotefuran and pyriproxyfen on adult fleas, flea eggs collection, and flea egg development following transplantation of mature female fleas (Ctenocephalides felis felis) from cats to dogs.

A novel spot-on formulation combining permethrin, pyriproxifen and dinotefuran (Vectra 3D™ spot-on solution for dogs) was evaluated in adult Beagle dogs in a study to determine adulticidal efficacy, egg laying inhibition and viability of Ctenocephalides felis felis eggs (development and emergence of fleas from the collected eggs). Prior to treatment sixteen dogs were checked for their ability to keep fleas 24 hours after infestation and were allocated to treatment groups: 8 dogs served as untreated controls, and 8 dogs were treated once with the tested formulation. The spot on was administered respecting the laboratory recommendations at a dosage of 65-126 mg/kg of permethrin; 8.9-17.4 mg/kg of dinotefuran and 0.8-1.5mg/kg of pyriproxyfen. Each dog was infested with 100 adult cat fleas ready to lay eggs after 72 hours spent feeding on cats. Dogs were infested 24 hours after treatment and then weekly during 63 days. Eggs were collected and counted 24 hours after each infestation and dogs were combed 48 hours after each infestation. Fleas were counted and removed. Collected eggs were placed in incubator to study their development in larvae and into newly emerged adults. A single treatment provided 99.7% adulticidal efficacy on fleas within 48 hours after treatment and controlled re-infestations for up to 30 days (efficacy >96.20%, p<0.05). The egg laying inhibition was over 92.3% for up to 29 days (p<0.05). The adult emergence inhibition remained 100% during 8 weeks after treatment and was 99.8% nine weeks after treatment (p<0.001).