Which term describes the sequence of events that enable transmission from an infectious source to a susceptible host?

• A. Infectious Disease
• B. Chain of Infection
• C. Reservoir
• D. Causative Agent

Answer: (B)

The sequence that enables transmission from an infectious source to a susceptible host is described by the chain of infection. This concept shows that transmission occurs only when all links are present: the infectious agent, a reservoir where the agent can survive, a portal of exit for leaving that reservoir, a mode of transmission to move the agent, a portal of entry into a new host, and a susceptible host ready to be infected. In athletic training settings, breaking any one link prevents spread—cleaning equipment and surfaces reduces the reservoir, good hand hygiene and PPE cut down transmission routes, isolating infected individuals stops exposure, and vaccination lowers the number of susceptible hosts. The other terms refer to single aspects rather than the whole sequence: an infectious disease is the illness itself, a reservoir is where the agent lives, and the causative agent is the organism causing the disease.