Resistência antiparasitária de diferentes populações de carrapatos(Rhipicephalus microplus) no oeste do estado de Santa Catarina, Brasil
Pazinato, RafaelKlauck, VanderleiGrosskopf, Rhayana KharynaDalla Rosa, LucianaVolpato, AndréiaBaretta, DilmarStefani, Lenita MouraSilva, Aleksandro Schafer da
Background: In Brazil, the tick Rhipicephalus microplus is a serious problem for beef and milk cattle due to the damagecaused directly to the animal. Ticks are responsible for major economic losses related to production, especially in breedsof European origin, prevalent in Southern Brazil. The use of most acaricides may allow the survival of some tick thattransmits this characteristic to future generations, consequently each successive treatment is a process of selection. Thelack of technical guidance on how to control ticks may contribute to the emergence of new resistant strains of ticks. Theobjective of this study was to test the effi cacy of antiparasitic drugs on tick populations (Rhipicephalus microplus) fromthe Western region of Santa Catarina, Brazil.Materials, Methods & Results: Thirty-one farms participated in this study and 70 engorged female ticks were collect fromeach property. They were divided into seven groups of 10 specimens each. Ticks were exposed to six commercial drugs:amitraz (A); cypermethrin, chlorpyrifos, and citronellal (B); diazinon (C); diclovós and chlorpyrifos (D); cypermethrin(E); cypermethrin, chlorpyrifos, and piperonyl butoxide (F); and one group was used as a control to validate the test (G:no drug). Tests with acaricides followed standard protocols, recommended for in vitro testing. The effectiveness of theproduct was calculated based on egg laying and hatching. The drug tested is considered effective if the result was morethan 95%. The number of farms with populations of resistant ticks were 13 (41.9% - group A), 2 (6.45% - group B), 15(48.38% - group C), 6 (19.35% - group D) and 12 (38.7% - group E). Ticks from the group F did not show resistance tothe tested products. i.e., all farms obtained 100% effi ciency. Among the products tested that showed the highest effi cacywere the combinations of three or two active principle as cypermethrin, chlorpyrifos and piperonyl butoxide (group F -...(AU)
Texto completo