Comparative study of transcription profiles of the P-glycoprotein transporters of two Haemonchus contortus isolates: Susceptible and resistant to ivermectin.

The objective of this study was to analyze the mRNA transcription levels of ten functional genes of P-glycoproteins (P-gp) in free life stages, eggs and infective larvae (L) and in endoparasitic stages, fourth larval stage (L) and adult males of two native isolates of Haemonchus contortus: resistant and susceptible to IVM. The IVM resistant isolate was obtained from sheep naturally infected with H. contortus, and the susceptible isolate (with no pressure to IVM) conserved since 1990.