Salmonellosis occurs worldwide; what approximate percentage of clinical cases are reported?

• A. Worldwide, about 1% of clinical cases are reported.
• B. Worldwide, about 50% of clinical cases are reported.
• C. Only a small proportion are recognized clinically, and as many as 30% are reported.
• D. In the United States, about 75% of clinical cases are reported.

Answer: (A)

Underreporting is the central idea here. Most Salmonella infections are mild or non-specific and people may not seek medical care, or they may not have stool testing or formal reporting to public health agencies. Because surveillance mostly depends on laboratory confirmation and mandatory or voluntary reporting, only a small fraction of true clinical cases make it into official statistics. That’s why worldwide the estimated proportion reported is about 1%, a figure that reflects substantial gaps between actual illness and what gets captured by systems designed to track it. The higher percentages listed would imply a much more complete, universal reporting network than is typical in many regions, including the United States, where even symptomatic cases are not routinely reported.