Larvicidal and persistent efficacy of an imidacloprid and moxidectin topical formulation against endoparasites in cats and dogs

Dogs and cats are often co-infected with endo- and ectoparasites. Roundworms of the genus Toxocara represent the most prevalent endoparasites in dogs and cats followed by hookworms of the genera Ancylostoma and Uncinaria. In the present study we have tested the anthelmintic efficacy of a new topical antiparasiticide which combines the insecticide imidacloprid and the macrocyclic lactone moxidectin for the simultaneous treatment and prevention of ecto- and endoparasitic infections in cats and dogs. Here, the efficacy against larval and immature stages of hook- and roundworms in cats was specifically investigated. Furthermore, the potential use of this product for the prevention of patent endoparasitic infections was addressed by demonstrating the persistent efficacy against Uncinaria stenocephala infections in dogs. Two controlled studies using experimentally infected cats showed 100% efficacy against third, fourth and immature adult stages of A. tubaeforme. Experimental infections with T. cati were eliminated to >97% and 91% concerning fourth and immature adult stages, respectively. Treatment of cats naturally infected with T. cati resulted in a complete removal of worm burdens. Evidence of persistent efficacy of the combination was obtained be treating dogs 18 days prior to infection with Uncinaria stenocephala larvae. In contrast to untreated control animals no worms were found in the intestines of the treated dogs 21 days post infection. No signs of local or systemic side effects were observed during these studies.