Response to the Letter to the Editor by Rob Armstrong.

In a recent Letter to the Editor, Armstrong raises concern that the design of the study reported by Six et al. was not consistent with the product label for treatment of Amblyomma americanum, since fluralaner was not re-administered 56 days after the initial treatment. The Authors disagree with this assessment and confirm that the design was appropriate, and therefore the results and conclusions for the entire study period are valid.