Pathogen \Path"o*gen\, Pathogene \Path"o*gene\, n. [See
{Pathogenic}.] (Biol.)
Any microorganism which causes disease; a pathogenic
organism; an infectious microorganism; a bacterium, virus, or
other agent which can cause disease by infection; -- opposed
to {zymogene}. The spelling pathogene is now archaic.
[1913 Webster + PJC]