In Vivo Acaricidal Effect of Linoleic Acid and Olive Oil Against Psoroptes cuniculi Mites in Experimentally Infested...

Psoroptes cuniculi is the most prevalent mite affecting rabbits worldwide. It is the primary cause of otitis in this species and significantly compromises animal welfare, leading to considerable economic losses. In search of alternative control strategies, several plant-derived oils such as olive, cinnamon, oregano, neem, and lemon oils have been evaluated in vitro for their acaricidal potential. In this study, the in vivo efficacy of extra virgin olive oil (EVOO) and linoleic acid (LA) was assessed as alternative treatments against P. cuniculi.

Twenty-four rabbits were experimentally infested with 150 mites placed in each auricle. After 139 days, animals were randomly allocated into four treatment groups (n = 6): 60% EVOO (with 0.1% DMSO in distilled water), 150 mg/mL LA, 4 mg/mL ivermectin (IV), and 0.1% DMSO in distilled water. Treatments were applied topically on day 0, and a second dose was administered on day 7. The infested area was quantified in vivo using a transparent grid on days 0, 3, 7, 10, and 14 after the first treatment application.

A marked reduction in infestation area was observed in the LA, EVOO, and IV treated groups, whereas lesion area increased in the negative control group. By day 14, infestation areas were nearly eliminated in rabbits treated with LA, EVOO, and IV. Final infestation areas were significantly lower than those observed in the negative control group (P ≤ 0.0001). Post-mortem evaluation on day 15 revealed no statistically significant differences compared with the in vivo measurements, indicating agreement between both assessment methods. No visible signs of irritation, erythema, or inflammation were observed during treatment.

These findings demonstrate that EVOO and LA exhibit substantial acaricidal activity against P. cuniculi under controlled experimental conditions and support their potential as alternative treatments for further investigation.