The first three quest mobs were up when I entered the zone and were killed easily. The 4th, the generian larva took about 3 hours of camping, 20 minute spawn time, killing the PH's "a planarian larva" not larvae. You get the resist disease clicky on turn in, which can be used from your inventory. You get an AA and anyone who is your group when you do the turn in gets an AA as well. You have to talk to some guy in the building SE of the bind guy in PoK to get the AA.
PH's are alleged to be planerian larva. these appear not to be the little wurm things like everything else. I don't know for sure, but I do know that I killed the planerian larva and that the generian larva wondered thru our spot.