It wouldn't make sense for Daryl to die of this new sickness, because, as the finger licking implies, he would be patient zero (after the pig) but the boy died first.
You could still be correct that he would die this season for some other reason but I doubt it, since Daryl is full of all kinds of merchandising. Then again, we all know that no one is safe. If I had to guess which main character would die next, I'd say Hershel. I really like that guy though.