[Effect of the strategic control of Amblyomma cajennense (Fabricius, 1787) (Acari: Ixodidae) on the population of Anocentor nitens (Neumann, 1897) (Acari: Ixodidae) in equines].

The study examined the impact of a strategic control program for the tick species Amblyomma cajennense on the population of another tick species, Anocentor nitens, in horses. Despite regular treatments, there was no noticeable reduction in the A. nitens population, possibly due to the lack of acaricide in the nasal diverticulum of the horses.

Research Methods and Overview

• The study attempted to evaluate the effect of a strategic control program implemented against the Amblyomma cajennense tick on the population of the Anocentor nitens tick species which infests horses.
• The control procedures were carried out using acaricide treatments every seven days, categorized into two batches: the first series began in April 2004 with eight treatments, while the second series started in July of the same year with five treatments.
• An essential element of these treatments was cypermethrin, a pyrethroid chemical, used at a concentration of 0.015% to eradicate the ticks. Pyrethroids are common synthetic insecticides aimed at disturbing the functioning of the nervous system in insects.

Measurement and Assessment

• The researchers inspected the infestation of A. nitens on horses monthly, particularly in the ear and nasal diverticulum before (from October 2003 to March 2004) and after (from October 2004 to March 2005) executing the strategic program of acaricide treatments.
• The severity of infestation was measured using a 0-3 scale to categorize the levels of tick infestation, where 0 represents no infestation and 3 signifies a severe infestation.

Key Findings

• Despite these intensive efforts, there was no significant reduction in the A. nitens tick population in the horses’ ears and nasal diverticulum. This could indicate that the control program was ineffective, or that other factors influenced the stability of the A. nitens population.
• The lack of acaricide penetration into the nasal diverticulum may be a possible explanation for this failure since it is a recognized location for A. nitens infestation. Therefore, the nasal diverticulum should be given special attention in future tick control strategies on horses.