Because of the medical and veterinary importance of ticks and the wide use of synthetic chemical substances such as permethrin (active ingredient of Advantage® Max3 - Bayer)for their control, this study evaluated the effects of different concentrations (206, 1031 and 2062 ppm) of the acaricide on the salivary glands of Rhipicephalus sanguineus semi-engorged females. Results showed that permethrin is a potent substance that acts morpho-physiologically in the tick glandular tissue, causing changes in the acini shape intense vacuolation in acinar cells, and disruption of the tissue by cell death process, with subsequent formation of apoptotic bodies, especially at higher concentrations, thus precluding the accurate identification of different types of acini. Importantly, it is demonstrated that permethrin acts on salivary gland tissue, as well as affecting the nervous system, accelerating the process of glandular degeneration, and interfering with the engorgement process of female ticks, preventing them from completing the feeding process.
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