Efficacy of two formulations of afoxolaner (NexGard® and NexGard Spectra®) for the treatment of generalised demodicosis in dogs, in veterinary dermatology referral centers in Europe

Background

A multi-centre field trial was conducted to evaluate the efficacy of afoxolaner based chewables (NexGard® or NexGard Spectra®) for the treatment of generalised demodicosis caused by Demodex canis in dogs under field conditions in France, Italy and Poland.

Methods

Client-owned dogs, diagnosed positive for Demodex mites by pre-treatment skin scrapings and presenting clinical signs of generalised demodicosis were included. Dogs were orally treated with afoxolaner three times at monthly intervals. Of the 50 dogs enrolled, 48 completed the whole study. Efficacy of the treatments was assessed monthly by Demodex mite counts and physical examination with special regard to the severity and extension of skin lesions.

Results

Treatments were well tolerated in all dogs and resulted in a rapid reduction of mites, with all post-treatment mite counts significantly lower than baseline. The number of mites was reduced by 87.6%, 96.5% and 98.1% on Days 28, 56 and 84, respectively. In addition, the skin lesion severity and extent scores as well as the pruritus were all significantly lower at all post-treatment visits compared to the pre-treatment assessment.

Conclusions

This clinical field study demonstrated that monthly administrations of afoxolaner in NexGard® or NexGard Spectra®, offered a convenient and reliable solution for the treatment of canine generalised demodicosis.

Efficacy of topically administered fluralaner or imidacloprid/moxidectin on dogs with generalised demodicosis

Background

Canine demodicosis is classified as localised or generalised according to the extent of the disease. Chronic generalised demodicosis is a difficult skin disease to treat and unlikely to resolve without therapy. This laboratory study compared the efficacy of two topical spot-on medications, fluralaner or a combination of imidacloprid and moxidectin, against naturally acquired generalised demodicosis in dogs.

Methods

Sixteen client-owned dogs with naturally acquired generalised demodicosis were randomly allocated to 1 of 2 study groups consisting of 8 dogs each. On Day 0, dogs in 1 group were treated once with fluralaner spot-on solution. Dogs in the other group were treated with the imidacloprid/moxidectin spot-on solution on 3 occasions (Days 0, 28 and 56) or weekly in severe cases. Mites were counted in skin scrapings and demodectic lesions were evaluated on each dog before treatment, and at 28-day intervals over the 12-week period. Deep skin scrapings were made from the same 5 sites on each dog at each examination.

Results

After administration of fluralaner, miticidal efficacy was 99.7% at Day 28, > 99.9% at Day 56 and 100% at Day 84. Efficacy in dogs treated topically with the imidacloprid and moxidectin combination, was 9.8% at Day 28, 45.4% at Day 56 and 0% at Day 84, and was significantly (P < 0.01) lower than the fluralaner treated group at each post-treatment time point.

Conclusions

A single topical administration of fluralaner eliminated Demodex sp. mites on dogs with generalised demodicosis. Topical imidacloprid/moxidectin combination treatment administered 3 times at 28-day intervals, or more frequently, did not eliminate mites from most treated dogs.