Pathogen (epidemiology)

A pathogen is an agent that causes disease. Typically the term is used with infectious agents. An infected organism is termed the host. For humans most pathogens are prions, viruses, bacteria, fungi or parasites.

History and etymology

The prefix patho- is derived from the Ancient Greek pathos (πάθος) which meant suffering, and implies disease. The suffix -gen is also from Ancient Greek (γενής) and means producer. The word pathogen came into use in the late 1800s .