Contribution of general esterases to pyrethroid resistant Triatoma infestans (Hemiptera: Reduviidae) from Argentina and Bolivia

the objective of this work was the study of the relative contribution of general esterases: á-napthyl acetate (á-na) and p-nitro phenyl acetate (p-npa) in pyrethroid-resistant t. infestans from these locations. we used deltamethrin-resistant populations previously collected in two areas in argentina (salta and la rioja) and one area in bolivia (tarija). in this study, frequency histograms of á-na and p-npa esterase activities, exhibited similar patterns between bolivian population and the susceptible counterpart. in contrast, argentinean field populations showed higher proportion of increased enzyme activity individuals. these results clearly demonstrated that resistances in argentinean and bolivian field populations are based on different mechanisms, suggesting that enzyme-based pyrethroid resistance in this species has multiple origins.