Anthelmintic action of different formulations of macrocyclic lactones on resistant strains of nematodes of cattle

作者：Cezar Alfredo Skrebsky^*; Vogel Fernanda S F; Sangioni Luis Antonio; Antonello Ana Maria; Camillo Giovana; Toscan Gustavo; de Araujo Luciana O

来源：Pesquisa Veterinaria Brasileira, 2010, 30(7): 523-528.

DOI：10.1590/S0100-736X2010000700002

• Macrolactones
• long action
• parasite resistance
• helminthes

Cezar A.S., Vogel F.S.F., Sangioni L.A., Antonello A.M., Camillo G., Toscan G. & Araujo L.O. 2010. [Anthelmintic action of different formulations of macrocyclic lactones on resistant strains of nematodes of cattle.] Acao anti-helmintica de diferentes formulacoes de lactonas macrociclicas em cepas resistentes de nematodeos de bovinos. Pesquisa Veterinaria Brasileira 30(7):523-528. Programa de Pos-Graduacao em Medicina Veterinaria Preventiva, Universidade Federal de Santa Maria (UFSM), Santa Maria, RS 97105-900, Brazil. E-mail: [e-mail]
The macrocyclic lactones (MLs) (avermectins and milbemycins) are endectocides broadly used in livestock and in some parasitic diseases of humans. In cattle, parasite resistance to MLs is emerging, and the appearance of formulations that differ in their pharmacological properties become complex the choice of the most appropriate drug to each case. In order to evaluate possible alternatives to restore the effectiveness of MLs on resistant strains of gastrointestinal nematodes, were tested, in this study, ten different treatments based on the MLs on a population of gastrointestinal nematodes of cattle which, known, was under pressure of selection by 1% avermectins. Additionally, was tested a benzimidazole. The efficacy of the drugs was calculated with basis on the reduction of eggs per gram of feces (EPG) of cattle. The resistance of each genus was evaluated by identification of the larvae, obtained from culture in the feces, pre- and post-treatments. The desired efficacy was not obtained using long action avermectins - with high concentration and in association - even with the application of high doses. The genera Cooperia spp., Haemonchus spp. and Trichostrongylus spp. were resistant to avermectins, and Ostertagia spp. to ivermectin. It was observed that, once established parasite resistance to the 1% MLs, the application of drugs, of this same chemical group, even in formulations of high concentration, association or in high doses, may not result in the expected efficacy.

• 出版日期2010-7