Werewolves were pretty universal across European mythology. If anything they were associated most often with Scandinavia and Northern Europe with the myths of skin-changers called hamrammr. The Book of Were-Wolves by Sabine Baring-Gould, published in 1865 describes the evolution of the werewolf myth and provides two origin points - Greece and Scandinavia. The Greek myths famously include Lycaon who was cursed into becoming a wolf (perhaps the earliest example of man-wolf transformation myth) and Scandinavia had the myths of the hamrammr who wore animal skins and took on the forms of beasts, famously represented in the Volsunga Saga when Sigmund and Sinfjolti wear wolf pelts and are transformed.

Baring-Gould posits that the Scandinavian myths were based on berserkers who would wear animal pelts, often of wolves and bears, and were famous for entering a state where they didn't respond to pain and fought ferociously like an animal. Baring-Gould writes that it's reasonable for people to tell stories of men wearing wolf pelts who enter these rages and cause violence, and for those stories to morph into tales of men becoming animals.

In the highly Christian societies of Europe, werewolves became treated essentially as another type of witch. Men who made pacts with the devil to take on the form of wolves for power and freedom. Baring-Gould relates several stories of men convicted of being werewolves and their stories of the devil and witchcraft, which differ from the Scandinavian and Greek mythological lycanthropy. It was this type of werewolf that became universal across European society, ranging from France to England to Eastern Europe.

Vampires, on the other hand, were indeed associated with Eastern Europe since before Dracula. This all comes down to a creature called the strigoi. Strigoi were the first creature in folklore to really resemble the modern vampire and formed the basis for the powers and behaviors of Stoker's Count Dracula.

In Universal Geography published in the late 1800s, Elisee Reclus describes the dangers that Romanians believed strigoi posed. Essentially saying that if someone with red hair died there was a chance they would change shapes and drinking the blood of young girls. Strigoi also possessed the ability to transform into an animal, turn invisible, and drain the life of their victims through their blood. All powers later made famous by Bram Stoker's Dracula.

The modern take on the strigoi was first published in 1689 by Johann Weikhard von Valvasor in The Glory of the Duchy of Carniola. He described the case of a man named Jure Grando who died in Croatia in 1656. The people of his village told tales of him coming back at night, killing people and sexually assaulting women - other hallmarks of the modern vampire myth as heavily influenced by Dracula. The people were able to repel Grando with a cross and attempted to pierce his heart with a wooden stake in Valvasor's retelling.

Other such tales of "real" strigoi and vampires almost exclusively came from Eastern Europe during this era to the point that they were associated heavily with Romania, Transylvania, and the Baltic states and made the region a natural fit for Bram Stoker to create the home of his fearsome fictional vampire Count Dracula.