Why does the Governor drink blood?

In Chapter 21 it states that the Governor is receiving vials of blood from the Raiders. It states that he drinks this. He used to get it from the Lab inside the wall, but cannot get it from there anymore. He is publishing Wanted posters for Fiona Tarsis and promises the Raiders that she is the reward, telling them to burn her body so no evidence exists.

Does he drink the blood in order to be immune to the bee flu or to have superhuman strength like the Level 10 beasts?