5.) Vampirism Virus
Featured in: I Am Legend, The Last Man on Earth, The Omega Man
Source: Varies. Bacteria that infects both the living and dead, biological warfare, a cancer cure gone wrong
Effects: Sensitivity to sunlight, severe garlic allergy, insatiable thirst for human blood

Richard Matheson's original novel, I Am Legend, has inspired everything from Night of the Comet to "Battlestar Galactica." Throughout three adaptations, the premise remains basically the same: chronicling the daily routine of one man living in a world full of things that want to murder him. The film serves as a good guide for what to expect if Swine Flu either manages to kill everyone or turn them into vampires. You go out for groceries, stop for the occasional staking, and dump some bodies off at the into the smoldering corpse pit of unimaginable depth. Later adaptations suggest playing golf off of a battleship like Will Smith in I Am Legend, or blindly firing automatic weapons into buildings like Charlton Heston in The Omega Man.

Worse than Pig Flu?: While the vampirism that ravages the planet in I Am Legend doesn't cause death, it does make us realize what terrible, violent, untrusting creatures human beings really are-and that's, like, way worse.