Sorry if i spoiled anything for you TIS, i presume that you watched when you posted..

I'm guessing you don't need to be bitten to turn to a walker ii must be like a cold virus where you are just infected. Remember at the end of the first season when the scientist whispered something to Rick, i'm think it has something to do with this.. Soon to be revealed im sure..

The Mafia Is Not Primarily An Organisation Of Murderers.
First And Foremost,The Mafia Is Made Up Of Thieves.
It Is Driven By Greed And Controlled By Fear.

Between The Law And The Mafia, The Law Is Not The Most To Be Feared

"What if the Mafia were not an organization but a widespread Sicilian attitude of hostility towards the law?"

"Make Love Not War" John Lennon