That's what I think. Whatever it is, it only affects humans and possibly primates (I think the Little Ones are monkeys or apes).
It causes rapid and selective mutation. It's a toss up right now if it was meant to be benign (to make a better human) or malign (to make a better soldier or a world with less/no humans or an alien attack).
I wonder if the smart ones were those infected soonest (the Zombie with the name tag) so they were scientists or techs working in a lab or facility. Or, they could have been trying to cure mental illness and so the more mentally ill you were, the better zombie you make.
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