Which elements comprise the chain of infection?

• A. Infectious Agent; Reservoir; Portal Of Exit; Mode Of Transmission; Portal Of Entry; Susceptible Host
• B. Direct Contact; Airborne Spread; Droplet Spread; Contamination
• C. Sterilization; Disinfection; Cleaning; Barrier Protection
• D. Hospital Accreditation; Patient Consent; Billing; Scheduling

Answer: (A)

Infection spreads only if six linked elements are present: the infectious agent, a reservoir where that agent lives and multiplies, a portal of exit through which the agent leaves the reservoir, a mode of transmission that carries the agent to a new host, a portal of entry into the new host, and a susceptible host who can be invaded. The option that lists Infectious Agent; Reservoir; Portal Of Exit; Mode Of Transmission; Portal Of Entry; Susceptible Host captures all six components.

In dental practice, understanding these links helps you see how infection control works to break the chain: sterilizing instruments and disinfecting surfaces target the agent and the reservoir; barrier protections and containment of saliva limit exits and routes of transmission; proper hand hygiene and personal protective equipment, along with safe work practices, reduce transmission and protect entry into the body; and vaccination or good health status reduces host susceptibility. The other options describe either methods used to control infection, or administrative aspects, or only partial aspects of transmission, but they do not enumerate the complete chain of six elements.