Efficacy of imidacloprid 10%/moxidectin 2.5% spot on (Advocate®, Advantage Multi®) and doxycycline for the treatment of natural Dirofilaria immitis infections in dogs.

•Combination treatment with moxidectin and doxycycline is adulticidal in dogs naturally infected with D. immitis.•Efficacy is 100% at 9 months from the beginning of treatment.•Efficacy for elimination of microfilariae is 99.9% after 1 month from the beginning of treatment.•Treatment is well tolerated and non-inferior to melarsomine at 12, 18 and 24 month from the beginning of treatment.