It was, indeed, a place where it congregated, rather heavily, but, as he journeys into the southern ruins, he doesn't detect a centralized source of it, either. Attempts to track the spread of the disease eventually come to the conclusion that it appeared in multiple places across the continent almost simultaneously, though it's difficult to say, as it seems to have been spreading for almost fifty years, and the multiple points of origin all seem to have a beginning date, within the same year, though that's as specific as he can get, on any of them. Despite this, the most affected individuals seem to be living closest to these ruins, though it's difficult to say, for sure, if they're the cause, or if it's mere coincidence.