Filthy Weapons (Combat)Source Heroes of the Streets pg. 29
You spread contagion with your weapons by covering their business ends in virulent muck and sewage.
Prerequisites: Knowledge (dungeoneering) 1 rank, Knowledge (nature) 1 rank.
Benefit: You can take a standard action to cover a weapon in decomposing waste, slimy filth, or other virulent agent. The next attack with that weapon that succeeds against a foe exposes the target to filth fever. If the attack is a critical hit, the filth fever has an onset time of 1 round, and a save DC equal to 10 + 1/2 your base attack bonus + your Intelligence modifier.