Probably not, unless it's in one of the novels
Do you think there's a real possibility that one of the writers could write a history of the Vidiians, with maybe an explanation as to what started the phage in the first place. I suspect that time travel could be involved. What if the Vidiians caused themselves the phage to appear with a time travel experiment gone wrong? As Picard dd say a "Chicken and the egg" paradox.