USAF Public Health Operations Block 1 Practice Test

The key idea is who is doing the searching for cases. Active surveillance means public health personnel take the initiative to find cases—they reach out to labs, hospitals, and clinics, verify diagnoses, and systematically collect data. This proactive approach aims to catch more cases and gather complete information, though it requires more resources. Passive surveillance, on the other hand, relies on routine reporting by health-care providers as part of their normal duties, so cases are reported only when clinicians or laboratories submit them to public health. This method is less resource-intensive but tends to yield underreporting and delays. So the statement that best captures the difference is that active surveillance involves proactive case finding by public health personnel, while passive surveillance relies on routine reporting by health-care providers. The other descriptions mischaracterize the methods or scope of surveillance.