[quote=@jasonwolf]
[@Wraithblade6]I think it'd be like a cancer as a disease. (I'll discuss with my biology professor about other possible similarities). Maybe over a few weeks it gets really spread through the body and then it basically kills the person as they have crucial functions stopped and rebuilt. Then the disease gets them back up because diseases exist to spread and killing things is actually not their plan.
[/quote]

I think we can combine these. Say, a bite from a vampire injects these 'vampire' cells in your body. These cells are extremely volatile, and act over the course of 3 days, giving the host superhuman abilities, but with an extreme energy cost, and due to the cells' unique chemical makeup, can only be satiated with blood.