He seems to be in a constant state of remorse for the things he's done. He wouldn't go into details, but he did hint at murder. Also in this catagory are the vampires who claim to have been changed by a visitation in a dream or by the apparition of a ghostly vampire. I have not personally met any such vampire, but I have met people who were visited but not changed. It is passed on through blood, sexual secretions, and occasionally saliva.
Transmission is usually deliberate and ritualistic.
It is unknown if this is an actual virus or if the effects are psychosomatic based on the archetype of the American Vampire. Nonetheless, the effects and changes associated with this type of vampirism are real. The process of change is the traditional exchange of body fluids in a ritual setting. Sex drive is first decreased then increased beyond the intensity before the change. Most vampires describe the sensation as like that of being on LSD during a mild trip.