Aliens, Plagues and Epidemics (S03E07)

Researchers are persistently faced with unknown bacterial strains that have enigmatic beginnings. Is it conceivable that some of history's deadliest pandemics stem from the deepest reaches of the cosmos or perhaps from alien influence? During the Middle Ages' Black Death, there were accounts of metallic vessels releasing a peculiar vapor. Fast forward to 2011, when NASA scientist Richard Hoover presented findings suggesting life within meteorites. Could it be that ancient extraterrestrial organisms, even microscopic ones, have played a role in the evolution of human events?