B S T R A C T
Ticks, particularly Rhipicephalus annulatus, pose significant threats to livestock, causing economic losses and
transmitting various infectious diseases. This study aimed to evaluate the potential acaricidal properties of garlic
oil and its nanoemulsion against ticks infesting cattle, Rhipicephalus annulatus through the evaluation of mortality
rate and morphological changes of the treated ticks. The study also included prevalence, risk factors, and molecular
confirmation of tick species. Genetic characterization confirmed the identity of R. annulatus. Our results
revealed a high prevalence of R. annulatus (46.9%) with a higher risk in male cattle (50%) than females (44.9%)
and a nonsignificant high infection (49.1%) in animals ≤ 1 year old. The acaricidal efficiency of garlic oil and its
nanoemulsion was concentration and time-dependent. The high concentration of garlic oil (20 mg/L) induced
complete mortality within 48 hours. The nanoemulsion formulation enhanced efficacy, particularly at 5 mg/L,
which exhibited rapid and substantial acaricidal activity. Scanning electron microscopy revealed morphological
alterations induced by garlic oil and its nanoemulsion, including changes to the anterior capitulum, dorsal, and
ventral cuticles. The study contributes to the exploration of effective, safe, and eco-friendly alternatives for tick
control. Further research is warranted to validate their efficacy under diverse conditions and assess practical
strategies.