Fluazuron Baits in the Control of Amblyomma sculptum Tick: Efficacy and Pharmacokinetics Using Guinea Pigs as an Experimental Model.

The tick Amblyomma sculptum is the vector of the bacterium Rickettsia rickettsii (which causes Brazilian Spotted Fever in humans). It can be found in domestic and wild animals, as well as humans. The objective of this work was to evaluate the efficacy of baits containing fluazuron in the control of A. sculptum in guinea pigs that were artificially infested. The work was conducted in two studies: descriptive pharmacokinetics and efficacy. Descriptive pharmacokinetics was assessed after administering one fluazuron-containing bait per animal (10 mg/kg). To determine the pharmacokinetic profile, blood samples were collected over several days. For the efficacy test, the animals were divided into four groups: a control group (untreated) and three treated groups that received a single dose of 10 mg/kg on days -21 (G1), -14 (G2) and -7 (G3). All animals were infested with A. sculptum larvae on day 0 and recovered on days +4, +5, +6, and +7. Fluazuron plasma concentrations increased rapidly, indicating rapid absorption, and decreased slowly. In all treated groups, engorged larvae with morphological and behavioral changes were observed. Although fluazuron did not show acaricidal efficacy, it was able to interfere with tick molting. Fluazuron was effective in controlling the A. sculptum tick in guinea pigs.