Chronic carriers are typically associated with dissemination of which organism?

• A. Salmonella Typhi
• B. Bordetella pertussis
• C. Campylobacter jejuni
• D. Yersinia pestis

Answer: (A)

Chronic carriers shed the pathogen long after symptoms have resolved, allowing ongoing transmission to others. Salmonella Typhi is the classic example of this pattern because some individuals harbor the bacteria in the gallbladder and biliary tract for extended periods and continuously shed in feces, enabling spread through contaminated food or water even when the person feels well. Bordetella pertussis is mainly an acute respiratory infection with shedding during illness rather than a long-term carrier state that sustains wider dissemination. Campylobacter jejuni usually causes a short, self-limited gastroenteritis, and chronic carriage is not a common driver of spread. Yersinia pestis transmission is tied to fleas and acute infections rather than a persistent human carrier state.