Observations on topical ivermectin in the treatment of otoacariosis, cheyletiellosis, and toxocariosis in cats.

The purpose of this study was to observe the efficacy of a topical pour-on formulation of ivermectin in the treatment of otoacariosis, cheyletiellosis, and toxocariosis in cats. Forty-five cats were treated. All cats received 2 to 4 topical applications of ivermectin on the skin between the shoulder blades in a narrow strip, 14 days apart. This practical treatment was effective in 96% (23/24) of cases of feline otoacariosis and in 100% (20/20) of cats with toxocariosis. All cats with cheyletiellosis (16/16) received 4 treatments and had resolution of clinical signs, but one Cheyletiella egg could still be found 45 days after the last treatment. The viability of this egg could not be evaluated, but the cats were still free of clinical signs on follow-up 6 months later. The treatment was well tolerated in all the animals. A few cats developed a transient small alopecic area and mild scaling at the site of application of the drug.