Which type of public health surveillance actively seeks cases rather than waiting for clinician reports?

• A. Passive collects data proactively; active waits for reports.
• B. Passive relies on reported cases from clinicians; active actively seeks cases; active yields more complete data but is more resource-intensive.
• C. Passive is more expensive; active is cheaper.
• D. Passive uses sentinel sites only; active uses complete population coverage.

Answer: (A)

Active surveillance is the approach that actively seeks cases rather than waiting for clinician reports. In this method public health teams go out to find cases—review hospital records, lab results, conduct interviews, or perform field investigations—so they capture more complete and timely data. This is more resource-intensive because it requires more staff time and outreach, but it reduces underreporting. Passive surveillance, by contrast, relies on clinicians and laboratories to report cases through routine channels, which is cheaper but can miss cases. The scenario described best fits active surveillance because it emphasizes proactive case finding rather than waiting for reports.