Connecting the DoTs: A Summoner Guide

[Sleigh]

Contagion doesn't snapshot, it just extends whatever was on there. Contagion is independent of what DoTs you currently have up. It counts this way on ACT.

Iron Jaws from BRD doesn't extend VB/WB, it restarts them, so it's purely based on which buffs you have and which debuffs are up on the enemy as you use Iron Jaws. ACT also takes this into account properly.