Each time you give a model a Deadly Pathogen, select one plague weapon that model is equipped with to upgrade (this cannot be a Grenade weapon or a Relic). In addition to the effects listed for that Deadly Pathogen, add1 to the Strength characteristic of that plague weapon. The Power rating of that model's unit is increased by 1.
Each time an attack is made with this weapon, an unmodified hit roll of 6 scores 1 additional hit. This is not cumulative with the Tollkeeper ability.