Tick generational treatment. Implementation of a methodology to erradicate Rhipicephalus (Boophilus) microplus tick resistant to macrocyclic lactones in a population management

Abstract

First oficial diagnosis of Rhipicephalus (Boophilus) mi­croplus resistance against macrocyclic lactones in Uru­guay was performed in 2010. This led to carry out a pilot project to eradicate resistant ticks. The methodology used and the results of the outbreak case and its boundaries is described. At the beginning, 16 farms were involved in the project with approximately 4000 cattle as an initial si­tuation, 100% dispersion (parasitic cycle) and a prevalen­ce of between 50 to 85% in ticks was present. Regarding hemoparasites, a dispersion of 100% was present. Preva­lence in babesiosis was between 67-100% and between 22-80% in anaplasmosis. After 24 months of suppressive treatments and the use of hemovaccine, a prevalence of 0.2% and 19% dispersion in ticks was registered, while the situation in hemoparasites was 20 to 33% of prevalen­ce, 31% dispersion in babesiosis and 12.5% in anaplas­mosis. Although the tick was not considered completely eradicated, in 9 of the 16 properties the situation is con­sidered to be in a very advanced stage control with very low parasite burden (prevalence 0.2%) and the remaining 7 can be considered free from ticks, due to the parasite was not found during 10 months. All actions and associa­ted costs are justified to fight against multiresistant ticks populations and prevent the formation of resistant ticks to all acaricides. This situation will not only jeopardize the technical feasibility to control the parasite, also would je­opardize the internationally recognized status of the cou­ntry in relation to food safety.