Rabid Fiend (3.5e Feat)
From D&D Wiki
Rabid Fiend [Abyssal Heritor, Monstrous]
Your fiendish blood allows to infect others with your bite.
Prerequisite: Bite attack
Benefit: Choose a disease whose base DC does not exceed 15, your bite attack now infects those bitten with the chosen disease. The DC for the disease in by 1 point, and an additional point per Abyssal Heritor Feat.
Special: Because the disease is transferred through a bite, only diseases with an injury infection can selected.
For every Abyssal Heritor Feat you possess before taking this one, the base DC of the disease you may choose increases by 1.The disease in your body causes complications with you health causing you to receive -2 hit points.