Board Thread:Theories/@comment-27435986-20151220162535/@comment-24930713-20151220224026

They vaguely touched on the topic, but it wasn't the focus for the particular chapter it was mentioned in. So they never explained what it was, or what would have been the outcome had Grisha not intervened. Though it seemed like those that got it had a fever and were bedridden because of it.

That being said, it seems possible. We'll just have to wait and find out. There's also something mentioned in the manga about Grisha, but I'm not sure if you've read that far, or whether it actually means anything.