Chronic carriers are typically associated with dissemination of which organism?

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

Answer: (C)

Chronic carriage means a person continues to shed the organism long after illness has passed, acting as a population source of infection. Salmonella Typhi is the classic example: after recovering from typhoid fever, bacteria can persist in the gallbladder and be shed in stool for long periods, allowing ongoing fecal-oral transmission and spread to others. This makes chronic carriers a key driver of dissemination in typhoid outbreaks.

The other organisms aren’t typically associated with a lasting carrier state that spreads widely. Bordetella pertussis causes an acute respiratory illness with transmission mainly via droplets; Campylobacter jejuni leads to acute gastroenteritis with brief or no chronic shedding driving spread; Yersinia pestis relies on fleas and animal reservoirs rather than human chronic carriage for human outbreaks.