How many zombie scenarios actually address the fact that fucking up any part of the human body starts making movement incredibly difficult?
Runners are impossible, they'd burn so many calories so quickly they'd be dead in a day, or less, much less in areas with risk of exposure, too hot or cold, body will just shut down.
So that leaves only slow walkers and crawlers, not exactly a dangerous threat.
And what is the pathogen itself feeding off of? It's not photosynthesizing energy is it?