They would have the same risk as any other wild caught worm. Perhaps even less if they are only eating one food course, of potentially healthy rabbits that an'rt foraging in areas where they'd collect L1 parasites. As per usual, having a fecal analysis done 1-2x's per year is a good idea. On that note, those farmed nightcrawlers are equally at risk for parasitism as any other worm, unless they are CB indoors, away from potential parasite vectors.