Chain of Infection

The chain of infection describes the linked elements needed for disease transmission: an infectious agent, a reservoir, a portal of exit, a mode of transmission, a portal of entry, and a susceptible host. Breaking any single link prevents infection.

Understanding the chain of infection guides where hygiene and infection prevention interventions — such as hand hygiene, surface disinfection, PPE, and isolation — will have the greatest impact.

Used in infection prevention training, outbreak investigations, and the design of hygiene programmes across healthcare, food, and agricultural settings.