PGP expression in Cooperia oncophora before and after ivermectin selection.

Area of Science:

• Veterinary Parasitology
• Molecular Biology
• Antiparasitic Drug Resistance

Background:

• Cooperia oncophora is a significant gastrointestinal nematode in cattle.
• Macrocyclic lactone resilience in nematodes poses a challenge to parasite control.
• P-glycoprotein (PGP) is implicated in drug efflux and resistance mechanisms.

Purpose of the Study:

• To investigate P-glycoprotein (PGP) gene expression in Cooperia oncophora isolates.
• To assess genetic selection and PGP expression changes following ivermectin (IVM) treatment.
• To compare PGP expression between sexes and treatment groups.

Main Methods:

• Quantitative real-time reverse transcription PCR (qRT-PCR) was used to measure Con-pgp-9 mRNA expression.
• Adult parasites from susceptible and resilient Cooperia oncophora isolates were analyzed pre- and post-IVM treatment.
• Amplified fragment length polymorphism (AFLP) analysis assessed genetic diversity and differentiation.

Main Results:

• Mean PGP concentrations were significantly higher in female than male worms (4-5 fold).
• No significant differences in Con-pgp-9 gene expression were detected between pre- and post-IVM treatment groups.
• A trend towards increased PGP gene expression was observed in male worms post-IVM treatment (p=0.091).
• AFLP analysis indicated no significant genetic bottleneck or differentiation within or between isolates after treatment.

Conclusions:

• Ivermectin treatment did not significantly alter Con-pgp-9 gene expression in Cooperia oncophora overall.
• A tendency for increased PGP expression in male worms warrants further investigation regarding sex-specific drug responses.
• Genetic diversity and population structure remained largely unaffected by ivermectin treatment in the studied isolates.