I'm trying to make the disease from the undead to transmit from one unit to another very quick. Par Example a peasant gets infected then it aproaches another unit and that gets infected like a plague. Please help me with triggers!
Sounds like what you want is the disease cloud that abominations have. You could probably just get away with tweaking the AoE and changing the tech requirements, and it should work just fine for what you want. No triggers necessary, except for the original infection perhaps. I don't know how you were planning on setting that up.
I wanted for example: a peasant uninfected approaches a diseased abomination; the peasant infected then approaches a healthy unit then that gets infected!