The way the disease spread was well documented.  Each Veela had dutifully described how she'd been contaminated, and, while Draco wondered idly who Hermione's source had been, it didn't really matter.  At least, he thought it didn't matter.   What he wanted - what his father wanted - was to figure out how she'd latched onto him.   How did any of this stain of Veela select their mates?  There didn't seem to be a common thread.  Two had already been married to theirs.  The other five had known theirs, but with such varying degrees of intimacy, it made no sense.  Some had been lovers.  Some had only known their mates casually before the disease grabbed them in its claws.  One had had the bad luck to have been in a building Muggles had tried to burn, her only connection to her future mate that he'd been there as well.  They hadn't known each other before that day and had no contact again until she'd somehow figured out he was her savior.