A doctor called it Wildfire 'cause of how fast it spread. It's in everyone. The water, probably, as much as the air.

[Daryl leaned back, put his weight on one foot as he went back to studying the kid. The cogs in his own head turning just as hard. One hand came up so he could bite at his thumb while his head dropped and he had to look up from under the heavy layer of bangs to see anything. The uncertainty and wariness in him obvious.]

Jenner never said how it got started, just that it did. And that once it went global, it didn't take more'n a few weeks 'fore everything went to shit.