alleryStart learning →The epidemiologic triad models infectious disease as the interaction of which three elements?
AReservoir, vehicle and vector
BIncidence, prevalence and rate
CAgent, host and environment
DExposure, outcome and control
Answer & Solution
Correct answer: C. Agent, host and environment
1. The triad is the traditional model of causation for infectious disease.
2. Its three corners are an external agent, a susceptible host, and an environment that brings the two together.
3. Reservoir, vehicle and vector belong to the chain of infection rather than the triad.
4. Incidence and prevalence are measures of disease frequency, not causal components.
_Source: CDC Principles of Epidemiology in Public Health Practice, 3rd Edition, section Causation_
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