Both the Leech brothers, hmmm..... Seven help us if Azul were here, too.

[Ugh. Ugh. Azul is a far slimier leech than either of the twins could ever hope to be. Knowing him, Azul would not only have antidotes prepared for these creatures, but also sell them at a steep markup. It's possible Jade would know, with his interest in flora and fauna..... But he has to admit, someone who runs a potion shop sounds more knowledgeable and promising than either of them.]

You're welcome to call any of them, if you think they might have some answers.