Molecular diagnostic of fipronil resistance in Rhipicephalus (Boophilus) microplus

Abstract

Rhipicephalus (Boophilus) microplus (Acari: Ixodidae) is the most important ectoparasite for livestock production. It causes huge economical losses in productivity (reduction of cattle weigth gain and reduced milk production) that added to the costs with its control (acaricide treatments plus labor) adds up to 2 billions of dolars per year in Brazil and 45 millions of dolars per year in Uruguay. The resistance to different classes of acaricides is spreading undiscriminated as a result of excessive selection pressure caused by the intensive use of this acaricides in the field over the years. It is very difficult to develop new acaricides drugs in a short period of time and because of this it is of great importance to preserve the efficacy of the existing molecules. Because of this, the development of molecular techniques of resistence diagnosis that will make it feaseble the monitoring the genetic susceptibility to acaricides, and obtaining faster results than the ones obtained with bioassays. For this it is nescessary to identify genetic mutations that are associated to all chemical groups that are available in the market. Nowadays there are just two techniques for molecular diagnosis, both related to sinthetic piretroid resistance. The goal of the present research is to contribute to the cattle tick control by developing a new molecular test that will diagnose the fipronil resistance. This project aim to determine if there is cross resistance between fipronil and ciclodiens, and if the rdl mutation described for dieldrin in R. (B.) microplus is involved with the resistence to fipronil. (AU)