A single subcutaneous administration of a sustained-release ivermectin suspension eliminates Psoroptes cuniculi infection in a rabbit farm

Background: Psoroptes cuniculi mites are the most common ear parasites infesting breeding female rabbits. The suffering rabbits show cutaneous signs of the infestation in the ears and are prone to secondary infections. Objectives: This trial was conducted to eliminate P. cuniculi in farm rabbits with a sustained-release ivermectin-loaded solid dispersion suspension (IVM-SD) suspension, and studied the stability of the formulation. Animals: There were 986 breeding female Hyplus rabbits naturally infected with P. cuniculi. Methods: All rabbits infected with P. cuniculi were subcutaneously administered with a single dose of IVM-SD suspension at 2 mg/kg body weight. Twenty-seven rabbits with severe infections were observed daily and examined on days 0 and 14 to score the lesions and count mites in crusts. Results: Fourteen days after the treatment no live mites were detected, demonstrating 100% therapeutic efficacy. The mean lesion scores decreased from 4.33 to 0.11 in the left ears and from 4.22 to 0.22 in the right ears. No reinfection occurred within 60 days of treatment. Conclusions: A single subcutaneous administration of the IVM-SD suspension at 2 mg/kg was effective in eliminating P. cuniculi infection in the rabbit farm.