It seems to me the whole Zombies plot is so simple ... Mind Control. Hitler was obsessed with Science and as we all know he wasnt exactly 'SANE'. The end of Nazi rule saw the dissolution of all of the Nazi Scientists work, or so its thought. Many scientist were transported across the world to the Allied Nations (America, England etc) to aid in there attempts of new, mind boggling scientific research (For Example 'Oppenheimer's' extraction to the US - You know the dude who created the Nuke). I think the whole 'Nova' project is the 'Americas' attempt to reboot what Hitler's army of scientists failed to create.
Mind control in the US's hands is evident even as far back as the Korean War 1950-53, and was at its hight in the 1960's with new theories of 'The New World Order' etc.
I know this is all guessing but is it possible the end result was not Mind Control, but Mind Destroying. Thus the outcome of brainless, flesh eatting zombies.