So eh … i tried the WQ Deworming Solution today.
The NPC told me something about a hostile worm infestation but i am pretty damn sure they have sent young Hemet Nesingwary in just before me. And he has not only killed the worm men but also the worm women and worm children. As i got the first two, it seemed that i just have eradicated an entire species, never to be found again.
So maybe we should change the quest to reintroduce worms into this habitat instead. There cant be an infestation if i need to kill twelve worms and there seem to exist only two of them.