Combinação de drogas antiparasitárias como uma alternativa para o controle de nematódeos gastrintestinais multirresistentes em ovinos

Abstract

This study was conducted to find effective anthelmintic treatments on a multi-resistant population of gastrointestinal nematodes of sheep, which was found resisting to all the classes of nematicidal drugs available in the Brazilian market. We took as a starting point the data obtained in a previous study performed in the targeted flock, in which were tested conventional treatments. Thus, using the calculated efficacy of the drugs (tested previously) for the genera of nematodes found in the flock, we selected drugs which, combined or used in higher doses, could improve the efficacy of the treatments. We evaluated the anthelmintic action of each treatment using the percentage of reduction of eggs in the feces, along with larvae cultures. A combination of moxidectin 1% + disophenol 20% showed 99% of efficacy, and combinations of moxidectin 1% + trichlorphon 10% and moxidectin 1% + levamisole phosphate 22.3% showed efficacy over 90%. Combinations of drugs, with different mechanisms of action, can provide effective anthelmintic treatments on multidrug-resistant populations of gastrointestinal nematodes of sheep.