Background and Aim: The soft tick Ornithodoros savignyi is distributed throughout Africa, including Egypt. It primarily attacks camels, cattle, donkeys, and cows; and rarely affects humans. This study evaluated the acaricidal efficacy of ethanolic Curcuma longa extract (Turmeric) on the second nymphs of O. savignyi and then investigated the safety of this herb in rabbits.

Materials and Methods: The nymphs were immersed in 10, 5, 2.5, 1.25, and 0.625 mg/ml ethanolic C. longa extract. An additional group was immersed in ethanol as a control. On the 1st, 7th, and 15th-day post-treatment, the mortality percentages, LC₅₀ and LC₉₅ were calculated. The ticks exposed to 10 mg/ml ethanol C. longa extract were investigated by scanning electron microscopy (SEM). Three male New Zealand White rabbits were orally administered 2 ml (two doses) of 10 mg/ml ethanolic C. longa extract, and another three rabbits were orally given two doses of 2 ml of absolute ethanol as a negative control. Histopathological examination of the kidney and liver hematology and the kidney and liver function was performed. Chemical analysis of the extract was determined by gas chromatography-mass spectrometry (GC-MS).

Results: The LC₅₀ and LC₉₅ were 1.31 and 15.07, 1.07 and 8.56, and 0.81 and 6.97 mg/ml on the 1st, 7th, and 15th day, respectively. SEM revealed that mamillae and spots on the surfaces of the treated ticks were not discriminating except for some clefts on the surfaces. The histological examination, blood profile, and biochemical analyses revealed no significant differences between the treated and untreated rabbits (p>0.05). GC/MS analysis revealed 50 compounds, and curcumene and t umerone were found to be the major constituents of this ethanolic extract.

Conclusion: The ethanolic C. longa extract produced a strong acaricidal effect on the second nymph of O. savignyi, and it was safe to use in rabbits.

Keywords: histopathology, scanning electron microscopy, soft ticks, tick control, turmeric.