Which statement best defines a carrier in epidemiology?

• A. An Individual Who Has the Organism but Is Not Infected
• B. An Individual Who Is Ill With Disease
• C. An Individual Who Is Immune
• D. An Individual Who Has Died From the Disease

Answer: (A)

The idea being tested is the concept of a carrier: a person who harbors a pathogen and can spread it to others without showing illness themselves. The statement describing someone who has the organism but is not infected fits this idea best because it captures the notion of carrying the pathogen without manifesting disease, allowing transmission despite not being visibly ill. Carriers can sustain and propagate infection in a population even when they don’t have symptoms. In contrast, being ill describes an active case, being immune means not susceptible, and dying means no longer contributing to transmission.