@nitsua60 What do you think about this? If the party does a little bit of research. They can learn about the disease. At that point, if any of them mention anything about coming up with a way to protect themselves, the druids will know about eyebright, and they can make an ointment with it that will give them immunity to the disease as well.
that way, all they need is the smallest sliver of foresight and they'll be good.