There were also stories about them making deals the the devil for magic powers, and drinking the blood of babies (i.e. blood libel), which is probably where some of the vampiric association comes from. Supposedly, a lot of descriptions of vampires in classic literature, including Dracula, were based on Jewish stereotypes or described as having Jewish features, but I don't know a lot about that. (Any litfags here who can confirm?)
The son of the preeminent italian rabbi (chief rabbi of rome) Ariel Toav wrote passovers of blood.
Here he lays the historic base of blood obtained by murder in use in rituals in history.
That wasn't just some conspiracy theory.
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The vampire myth is another thing though.
I've looked at the vampire myth and found that it doesn't have quite as much overlap with jewish themes as one might think. Although 18th and 19th century had quite a lot of it (with early movie with bela lugosi even just wearing a davids star), before bram stoker the connection isn't as strong. In bram stoker's dracula, you have parasitic nature, hoards of gold, aversion to the crucifix. Also at the end when they try to track down dracula's remaining box, it turns out that it has been received by a jewish man, which implies he was an accomplice of dracula.
However in the Romanian myth of the strigoi, which is the early roots of vampirism in western culture, the only possible link is that the strigoi were nocturnal humanlike creatures that preyed on children. Just that is a pretty weak link as we know quite a bit about the strigoi and how you were supposed to deal with them.
For example, the original strigoi weren't killed by a stake through the heart. It was there to secure them in place so they can't go out and prey on children. And it had to be right kind of wood. Yew and two others were specified.
The closest link I've read, and this is far from scholarship and more conspiracy theory territory, is that degenerative porphyria diseases or tays sachs may have given rise to the myth. Because this might result in the strange appearance.
Tays sachs is a congenital ashkenazi disease that causes the body to disintegrate at the cellular level if I understand it correctly.