Originally Posted by Luckless
I've been bit and scratched by humans before. (Damn kids... Mother said they were little angels, and only needed me to watch the little demons for a few minutes while she ran for an appointment.) Didn't die from that...
I'm sure it's all about infection. For example you're scratched, then grabbed by a super infection/fever. It quickly kills you off, then
you turn like everyone else that dies.
That's why they pointed out that Herschel didn't have a fever after the ticking baby time bomb saved him.