I'm surprised more people aren't talking about the fact that Daryl was not only eating pork, but was licking his fingers and shaking hands with the sick kid as well. Didn't he even lick his fingers after that too? That venison was his signature too.
He must have one helluva an immune system because you know they won't let him get sick or get killed off.
If the pork was fully cooked it wouldn't hurt him a bit. And I think that whole scene and the pig laying doing nothing was to have people think it was coming from the pigs. I think it's all smoke.
Whatever it was killed the kid pretty quick. There's no way Daryl wouldn't show signs of being sick then. And look how many were eating.
My theory The kid was feeding rats to the walkers, got sick, goes into the shower and coughs over the open water barrel and it just goes from there.
Or, in feeding the rats, he gets scratched or infected somehow and gets the fever, dies and turns. Simple as that. He may or may not have infected the water hacking all over it.
Does anyone remember if the kid had bleeding eyes when they showed him laying on the floor after he turned?