What is a notifiable disease?

• A. A disease that must be reported to public health authorities by law to enable rapid detection, investigation, and response to protect population health.
• B. A disease that is never reportable and does not require surveillance.
• C. A disease that only occurs in travelers.
• D. A disease that is diagnosed only by symptoms.

Answer: (A)

Notifiable diseases are diseases that must be reported to public health authorities by law so they can rapidly detect, investigate, and respond to protect the health of the population. This legal requirement creates a surveillance system that helps identify outbreaks, trace contacts, implement control measures, and inform necessary public health actions quickly. The other descriptions don’t fit because a notifiable disease is not something that is never reportable; it is specifically defined as one that must be reported. It’s not limited to travelers, since many notifiable diseases can occur in anyone. And reporting isn’t defined by symptoms alone; many notifiable diseases require confirmation through diagnostic testing, though the obligation to report can be triggered by suspicion as well as confirmed diagnoses.