My Marksman recently got the Infect spellbook, and I tried it out on a battle with some melee Orcs. It ended up spreading to their entire team, then one of the Orcs ran over to us, and infected my entire team! I was under the impression it only spreads on the turn that it was cast.
This is obviously a problem, since making everyone (including my team) diseased isn't particularly useful.
Is Infect really only useful against enemies that are exclusively range-based? Is there a way to prevent it from spreading to my team, besides only using it against non-melee enemies, and avoiding melee attacks while they're infected?