Good point! Get better soon!
yeah, but who would you be catching these viruses from... the dead?
Well, yeah. Dead bodies are highly unsanitary, and once they get in the water, you start getting dysentery and cholera spreading quickly, along with other nasties. And in a post-apocolyptic world, very like current war zones and third-world nations, between lack of potable water, malnutrition and/or uncertain food supplies, and lack of pasteurization and refrigeration, it's a harder to avoid the viruses and bacteria of the wild.
The rule of Zombieland I wish they'd covered was "Zombies travel in packs, DON'T RELY ON A DOUBLE BARREL SHOTGUN YOU FOOL!"