Hi

I was reading about New Phyrexia and noticed some things it seems I don't understand:
I was assuming the invaders of Mirrodin must be survivors of Phyrexia who escaped Yawgmoth's defeat and managed to establish a foothold on Mirrodin which, I read somewhere, had been somehow influenced or weakened by glistening oil. Since the Phyrexians were busily gathering valuable ressources all over the multiverse, it isn't a big stretch to imagine that there might be enough of them left, including powerful leader types.
Now it seems the glistening oil now works like some contagious technological illness that turns people who touch it into Phyrexians... How did the Phyrexians come to Mirrodin? And do they still breed newts which are compleated into Phyrexian machine-creatures?