Instructions
Travel to the headquarters of one of the three main vampire clans--the Warriors of Quarra, the Mages of Aundae and the Shadows of Berne. The Quarra are located in the Dwemer ruins in Druscashti, east of Khuul; the Aundae reside in the Ashmelech cavern, on an island southwest of Dagon Fel; the Berne stay in the Dwemer ruins in Galom Daeus, west of Tel Uvirith.
Engage in battle with one of the vampires. The vampire may attempt to battle you from a distance with magic, so you will need to move in close to the vampire to trigger hand-to-hand combat.
Force the vampire to damage you with physical attacks in order achieve infection. The disease will not infect you through magical attacks, but there is a small chance of infection with each physical attack. Escape from the battle once you become infected.
Find a place to rest and sleep for three days, which is how long it takes for the infection to completely transform you. On the third day, you will wake up from a nightmare, which signifies that you are a vampire.