patogenezise

Pathogenesis is the biological mechanism by which a disease develops. In some languages, the term patogenezise is used to describe the same concept. It encompasses the progression from initial exposure to a causal agent through colonization and replication, tissue invasion, host response, and ultimately clinical symptoms, organ dysfunction, and often recovery or chronic sequelae.

The sequence typically begins with exposure or entry of a pathogen, followed by adherence to host cells, colonization, and, if conditions permit, invasion and spread within the host. As the organism multiplies, the host immune system responds with inflammation and other defenses. Tissue damage can result from direct effects of the pathogen, such as toxins or enzymes, from the host immune response, or from disruption of normal tissue architecture. Clinical disease emerges when enough tissue injury or dysfunction occurs to produce symptoms and measurable organ impairment.

Determinants of pathogenesis include pathogen virulence factors (adhesins, invasins, toxins, immune evasion molecules), the infectious dose, and tissue tropism. Host factors such as age, genetic background, nutrition, comorbidities, and immune status, as well as environmental factors like exposure route and co-infections, shape disease outcome. The interplay of these factors determines the onset, severity, and course of disease.

Studying pathogenesis uses frameworks such as Koch’s postulates (historical) and modern molecular postulates, together with experimental models and epidemiological evidence. Understanding pathogenesis informs prevention and treatment, from vaccines and antimicrobials to strategies that target virulence factors or modulate the immune response. Pathogenesis is applicable to infectious diseases and to non-infectious conditions where cellular pathways malfunction or malignant transformation drives disease development.