a pathogen that can invade the host only after establishment of a primary pathogen —note 1. once established, secondary pathogens may or may not be able to induce disease on their own —note 2. secondary pathogens may include pathogens that can invade the host after insect infestation, particularly by bark beetles —see predisposition, primary insect, primary pathogen, secondary insect, secondary pest This definition last updated 08/02/2008