I know we're probably going to find out tomorrow but I might know how they died.
Mosquitos.HELLO?!Mosquitos suck out blood and then go to another to suck on theirs.
Now what must have happened is that the mosquito sucked out blood from a walker,went on Violet/Patrick and 'delivered' it.
Do you think this is how it happened?Tell me down below!
EDIT:I just noticed,since most people say it's waterborne then it makes a LOT of sense.Mosquitos like dirty water,in this case the infected water.So if it goes to drink the water,then onto Patrick or Violet....you know. o_o