In
biology, a
pathogen (
pathos “suffering, passion” and -γενής
-genēs “producer of”) in the oldest and broadest sense is anything that can produce
disease, a term which came into use in the 1880s. Typically the term is used to describe an infectious agent such as a
virus,
bacterium,
prion,
fungus,
viroid, or
parasite that causes disease in its
host. The host may be a human, an
animal, a
plant, a
fungus, or even another micro-organism.