Scanning electron microscopy of Haemonchus contortus exposed to tannin-rich plants under in vivo and in vitro conditions

► By SEM, H. contortus exposed to tannin rich materials showed structural damage. ► Changes were found in the cuticle including aggregated material in the buccal area. ► Changes in the female reproductive system were found in vitro but not in vivo. ► The structural changes might affect worm motility, nutrition and reproduction.