So far this season...
Hershel: Leg chopped off after zombie bite.
T-Dog: Severely bitten, then self-sacrificially eaten alive in effort to buy Carol time to escape.
Rick and Lori's baby: Born during a self-sacrificial C-Section, reluctantly administered with a knife by Maggie.
Lori: Bullet administered by son Carl to prevent "turning" after fatal C-Section.
Dark times, the Zombie Apocalypse.