Molecular quantitative assay for esterase-mediated organophosphate resistance in Rhipicephalus microplus.

The use of pesticides is the main tool to control infestations of the cattle tick Rhipicephalus microplus, and organophosphate (OP) is one of the most used compounds for this purpose. Carboxylesterases (ChEs) are targets for OP pesticides in arthropods, and acetylcholinesterase 2 (AChE) and esterase 1 (EST) are metabolic enzymes involved in the xenobiotic detoxification process. The increase in the synthesis of these enzymes can be detected by the quantitative polymerase chain reaction (qPCR) assay, which was used to identify cattle tick populations resistant to OP pesticides.

New tick records in Rondônia, Western Brazilian Amazon.

In the present study, we provide new tick records from Vilhena Municipality, in the Southeast of the State of Rondônia, Northern Brazil. Ticks collected from a capybara, Hydrochoerus hydrochaeris (Linnaeus), were identified as Amblyomma romitii Tonelli-Rondelli (1 female), and Amblyomma sp. (1 larva).