In my game I found the origin of the plague, it was a malfunction in the air filters in a new found colony. The result was that the pox expanded from there afther silently infecting the colony and all went down hill from there. The Irassians were a big empire already, so the civil and commercial traffic help the fast spreed of the plague (we don't have an estimated time of incubation, but for what I found I theorise that the pox started to produce it's lethals sintoms way afther the thing was contagious, so you can have one ship carrying an infected for more or less two planets before the sick died of the disease)Sorry, I don't really understand what you are saying.
For the Irassians, I was thinking that given that the Irassians were absolutely massive racists and convinced of their own superiority, perhaps they messed around too much with genetic engineering, leading to the pox arising. In the present time, that could tie into a crisis where if your or the AI does too much genetic engineering, then you might accidentally create a mind worm parasite that hijacks biological entities. So more or less what you were saying.
talt