Vampires In Folklore
In European and Russian legends, they are dead bodies that are animated by an evil spirit, so it's basically a form of demonic possesion. In one Russian tale, the Vampire spirit will flee the body (if it's destroyed) in the form of vermin, to infect another corpse elsewhere.
Other legends portrayed them as people who were evil - or tainted by an evil curse - in life and were thus doomed to perform more evil after death by arising as a vampire. This included witches, werewolves, and gouls (from Arabian folklore, humans who ate the flesh of other humans for power in life).
With the rise of Christianity, those who were excumunicated by the Church (supposedly for commiting an evil act, but in reality it could have been politics) could not be buried in hallowed ground, and were doomed to arrise as a vampire.
All three views are compatible, and count as a form of Undeath. It's only Victorian literature that added romantic elements to something that was essentially hideous and repulsive - an animated corpse, that stank of death and spread disease by it's breath alone.
The seperate race thing came much latter, with modern literature.
That's a quick overview; there are plenty of good books on myths and legends that you can consult if curious, and others on the list more schooled in the subject than I.
Grey.