Tetanus tweaks.

Makes tetanus slightly less brutal on the sufferer (reduced the constant
falling on your face part) and harder to contract in the first place,
makes tetanus respect the infection resistance/immunity traits, adds
chance of infection to falling in spiked pits, reduces infection chance
from bear traps (they don't generally create the type of wounds that
tetanus thrives in), and makes tetanus respect medical bionics.