Ozone as a potential acaricide: Evaluation of reproductive parameters and detection of morphophysiological changes in reproductive tissue of female ticks of Rhipicephalus linnaei

Ticks of the species Rhipicephalus linnaei are responsible for significant medical and veterinary importance diseases, therefore several studies have sought to find effective control methods for this parasite. The indiscriminate use of these synthetic chemicals has caused disadvantages, such as the selection of resistant tick strains, toxicity in non-target organisms, and environmental contamination through the generation and accumulation of residue. These facts stimulate the search for more sustainable control strategies, which are less harmful to animals and the environment while being efficient. Furthermore, in previous studies, seed ozonated water was applied in semi-engorged females, which caused morphophysiological changes in the salivary glands and the integument of the same species. Thus, the present study aimed to evaluate the ozone as acaricidal potential against the species R. linnaei, after exposure (immersion) of engorged females in ozone (ozonated water 3 mg/L). For this purpose, 15 engorged female ticks were used, with bioassays conducted in triplicate to evaluate both changes in biological parameters (weight of the engorged female before laying, weight of the egg mass, and hatching rate-values used to calculate the egg production index (EPI) and control rate) as well as morphophysiological alterations in the ovaries and Gene's organ, which are fundamental organs for the reproductive success of these ectoparasites. The results presented demonstrate that ozonated water in the concentration of 3 mg/L has the potential to cause not only morphophysiological changes in oocytes and Gene's organ's tubular glands in exposed females of R. linnaei, as well as its biological parameters, demonstrated by a control rate of 40.69 %. The bioassay results demonstrate that ozone is a promising method for controlling dog ticks. The data shows ozone effectively reduces reproductive capacity, indicating it as a tick management solution.