pathogener

Pathogener are biological agents capable of causing disease in living hosts, including humans, animals, and plants. They comprise a diverse set of organisms and agents, such as bacteria, viruses, fungi, protozoa, helminths, prions, and certain toxic products produced by microbes. Disease results when the pathogen overcomes host defenses, establishes infection, and causes tissue damage or dysregulates immune responses.

Pathogenicity is determined by virulence factors that enable attachment and entry into host cells, replication, dissemination, and evasion of host immunity. Examples include adhesins, invasins, secreted toxins, and mechanisms to avoid detection by the host immune system. Host susceptibility, prior immunity, and environmental conditions influence disease outcomes.

Pathogens can be transmitted through multiple routes: direct contact, respiratory droplets, ingestion of contaminated food or water, vectors such as insects, vertical transmission, or contaminated surfaces. The same agent may cause different diseases in different hosts, dependent on tissue tropism and immune status.

Detection and management rely on clinical assessment and laboratory testing, including culture, microscopy, molecular diagnostics, serology, and, when appropriate, genomic sequencing. Public health surveillance tracks incidence and spread, guiding interventions.

Prevention and control efforts include vaccination, good hygiene and sanitation, safe food and water practices, vector control, infection prevention in healthcare settings, and prudent use of antimicrobials to limit resistance.

This is about pathogens in general; for disease-specific information, refer to individual pathogens or disease articles.