I have recently come across the idea of a vampire's drudge: a slave to do a vampire's bidding. However, I have not been able to find the origin of it. In fact, the only references to it I am able to find are unsourced replies to generic questions on sites such as Wikianswers (the questions being of the nature "What is a vampire's slave?" and the answer being "A drudge"), fan-fictions and a series of fiction books called the Chronicles of Vladimir Tod.
What I am looking for is the origin of the term "drudge". I understand the nature of the drudge -- the vampire's servant -- but I am looking for the origin of the actual term: did it come from mythology or is it the creation of an individual author and so on?
EDIT: I had made the connection between drudgery and drudge: it makes sense that a person designated to do hard or menial tasks could, from drudgery, be called a drudge; so I just want to stress I'm after the origin of using the word to mean a vampire's servant.