The pathogenesis of a disease is the mechanism that causes the disease. The term can also describe the origin and development of the disease, and whether it is acute, chronic, or recurrent. The word comes from the Greek pathos (“disease”) and genesis (“creation”).

Types of pathogenesis include microbial infection, inflammation, malignancy and tissue breakdown. For example bacterial pathogenesis is the mechanism by which bacteria cause infectious illness.

Most diseases are caused by multiple processes.

Often, a potential etiology is identified by epidemiological observations before a pathological link can be drawn between the cause and the disease. Recently, pathological approach can be directly integrated into epidemiological approach in the interdisciplinary field of molecular pathological epidemiology (MPE).

MPE can help to assess pathogenesis and causality by means of linking a potential etiologic factor to molecular pathologic signatures of a disease.

Thus, the MPE paradigm can advance the area of causal inference.