Hmmm good calls, they're supposed to be annoyances not tpk material. The spitter zombie and the berserker zombie will be more powerful but not debuffing ...
Also, i plan on giving them, like, 4 vials of antidote to the disease, and none of the zombies will coup de grace, they like eating their prey alive.
But yah, I'll retool the duration.
EDIT: Done. I'll maybe make them meaner with longer durations on the next inquisition into zombie land, when they will be around level 7 and have access to things like iron heart surge, panacea, and other nice things ^^