Have any other groups of players just allowed the plague to spread? My group ignored it for a while, and now is just trying to enact a quarantine over the human district to prevent the plague from taking the entire city. They've ignored the repeated references to the vrykolakas, so that's not even going to work. The boggards and serpentfolk have come into repeated contact with plague victims, so I guess they're next. (Akarundo is dead, so he won't be intervening.)
I think the vegepygmies will be weaponizing the plague against the troglodyes and charau-ka, and certainly they'll be moving among the dying populations spreading spores. Four of the five caravans have been infiltrated by the serpentfolk patrols and will probably either die or leave town. Yog'oltha and M'deggog will likely do what they can, then bail.
So the PCs will probably be heading to Ilmurea with no backup. Is this the first time this has happened, or might any of you be able to tell me what it's like?
(I don't need suggestions on how to softball this for the PCs, btw; I know how to dumb things down if I choose to do so.)