Weak phenotypic reversion of ivermectin resistance in a field resistant isolate of Haemonchus contortus by verapamil
Recent advances in anthelmintic resistant phenotype reversion by Pgp modulating drugs in ruminant nematodes indicate that this can be a useful tool to helminth control. The aim of the present study was to evaluate the efficacy of ivermectin (IVM) in combination with verapamil (VRP), in oil or water-based vehicle, against an IVM-resistant field isolate of Haemonchus contortus through a larval migration assay and experimental infection trial. In the in vitro assay was observed a phenotypic reversion of H. contortus resistance to ivermectin at a high concentration of VRP, increasing IVM efficacy from 53.1% to 94.3. In the in vivo trial, IVM + VRP demonstrated 36.02% efficacy compared to the 7.75% of IVM alone. The vehicle formulation showed no influence in efficacy. These are the first results demonstrating the effect of VRP as a partial IVM-resistance phenotype reverser in a field isolate of IVM-resistant H. contortus experimentally inoculated in sheep.
| Main Authors: | , , , , , , |
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| Format: | Digital revista |
| Language: | English |
| Published: |
Colégio Brasileiro de Patologia Animal - CBPA
2011
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| Online Access: | http://old.scielo.br/scielo.php?script=sci_arttext&pid=S0100-736X2011000900002 |
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