Die, wait till it crawls out, resurrect...........Get a maul, splat someones head flat, resurrect..........Make a big bonfire and burn someone to bones, take bones to chapel and resurrect.

I see a great big fat plothole forming.........

Basically a 100% cure would be death, wait a bit then resurrect. Two instances of the tadpole crawling from dead host breaks the plot. I am unsure why someone with high wisdom especially a cleric wouldn't come to this conclusion.