Differentiate passive and active surveillance with examples.

• A. Passive: routine reporting by health facilities; Active: staff actively seek cases through case finding and records review.
• B. Passive: staff actively seek cases; Active: routine reporting by health facilities.
• C. Passive: surveillance generates no data; Active: collects all data.
• D. Passive: laboratory surveillance; Active: community surveys only.

Answer: (A)

Understanding how data are collected is key: passive surveillance relies on routine reports from health facilities, while active surveillance involves public health staff going out to find cases themselves.

In passive surveillance, clinicians or labs submit information about diagnosed cases to health authorities as part of normal operations. This approach is less resource-intensive and good for ongoing monitoring, but it can miss cases that aren’t reported. Notable examples include routine reporting of notifiable diseases by hospitals or clinics and laboratory reports that are automatically sent to public health offices.

In active surveillance, public health teams proactively seek out cases. They may conduct case finding, review medical records, contact facilities, or carry out targeted surveys to identify cases that might not be captured through passive systems. This method is more resource-heavy but yields more complete and timely data, and it’s often used during outbreaks or for focused studies.

So the best description matches passive as routine reporting by health facilities and active as staff actively seeking cases through case finding and records review. The other options either swap the activities, claim no data are generated, or restrict active surveillance to community surveys, which doesn’t reflect how these systems operate in practice.