Vampires Options

[D3TOX]

Don't think this is a spoiler, but for vampires im on one of the theifs guild quests, and there is vampires, tried my best not to contract the disease, anyway I took out about 4 of them, then I came to this room and killed one of the vampires, then 2 of them came at me, so I killed one of them and the other one hit me a few times with his sword, but before it came up i contracted the vampire disease, so i reloaded the game and did it again and he hit me about 3 times, but it did not come up with it, if a vampire hits you does that mean 100% of the time you get the disease or not? also after killing a vampire do your become a target like they get you in your sleep etc, and does the dark brother hood vampire hate you?