Vampires have always been a passing interest for me; so as I was reading godawful vampire fiction the other day, a thought came to me . . .
'What if vampires were real, yet not supernatural?'
This led me to think of them as an ethnic group, which led to this map. The Upir are an ethnic-linguistic group in Eastern Europe, who were formed by a mass genetic mutation. Generally they tend to have slightly lighter skin than their other brethren, which is the main factor of the mutation. The other is that they have slightly longer canine teeth, though this is not always noticeable.
By the time this map takes place, they are all throughout Europe, though they've been treated as second-class citizens in Europe for centuries.