This article is from the Vampires FAQ, by BJ Kuehl bj@alpha1.csd.uwm.edu with numerous contributions by others.
There are many possible routes of becoming a vampire. Some of the more
prevalent mythological routes are:
- Suicide
- Excommunication, dying unbaptized/apostate, or anything else that
puts one "outside of the church"
- Being a wizard/witch
- Having been a werewolf
- Having your parents curse you, as in "May the earth reject you!"
- Being born with teeth or a caul (sometimes specifically a red caul).
In this case, it may be possible to prevent the inevitable by burning
the caul and feeding the ashes to the baby.
- Having a cat or other animal jump over your corpse before it gets
properly buried.
- Possessing red hair.
- Being a victim of an unavenged murder.
- Being a seventh son.
- Being sexually promiscuous.
- Being the offspring of a human woman and a demon or incubus.
- Being bitten by a vampire. In some versions, the victim has to die from
the bite to become a vampire; in others, three bites are necessary.
- Drinking the blood of a vampire.
If it is suspected that someone is likely to become a vampire, it is
possible to prevent the occurrence by using one or more of the methods
listed in 2.07 for destroying vampires or by burying the suspect body
face downwards. In Eastern Europe, it was common to periodically check
bodies to see if they showed any signs of vampirism. In China, potential
vampires were not buried until after they had decayed considerably.
 
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