Jerry went to the farmers market looking for something natural. He saw some real honey still in the comb, packed in a clear plastic container. That was about as real as it gets, except for one problem. The bees that made that honey were fed a diet of high-fructose corn syrup, from GMO corn. Jerry tasted a sample and something weird happened.
Jerry's blood was the product of two generations of GMO exposure which altered a few molecules in the blood cell walls which allowed for receiving connections from viral molecules found in the honey.
The combination accelerated the reproduction of a dangerous airborne strain of a flesh-eating virus which had a six month incubation period. In other words, unlike diseases with very short incubation periods that burn themselves out before they spread very far, this virus spread around the entire planet before the adverse effects started to kick-in. One day people started feeling ill and staying home from school and work. Nobody could do anything so they mostly stayed in bed. Then their flesh liquified as they lay in bed. The streets were completely empty. Everything was quiet.