Active Surveillance
This scenario describes active surveillance, where health personnel proactively visit healthcare facilities to systematically collect case information rather than waiting for reports to be submitted. 1
Key Distinguishing Features
Active surveillance is characterized by surveillance personnel initiating contact with data sources and actively seeking out cases, which is exactly what occurs when a health team visits hospitals and laboratories weekly to gather influenza information. 1 This contrasts fundamentally with other surveillance types:
Why This is Active Surveillance:
- The health team initiates the data collection process by going out to hospitals and laboratories 1
- Personnel actively search for and gather case information rather than waiting for facilities to report 1
- Regular, systematic visits occur on a scheduled basis (weekly in this case) 2, 3
- Direct contact with data sources ensures comprehensive case ascertainment 3
Why This is NOT the Other Options:
Passive Surveillance (Option B):
- Passive systems rely on healthcare providers initiating reports as part of routine practice 1
- Data flows from facilities to health departments through established reporting channels without active solicitation 1
- The CDC's routine influenza monitoring uses passive surveillance where providers submit data voluntarily 4
Sentinel Surveillance (Option C):
- Involves selected reporting sites or populations monitoring disease trends 1
- Uses a sample of facilities rather than comprehensive visits to all hospitals and laboratories 4
- The CDC's ILINet uses approximately 110 WHO collaborating laboratories as sentinel sites 4
Syndromic Surveillance (Option D):
- Monitors symptom patterns or syndromes rather than confirmed disease cases 1, 5
- Relies on prediagnostic data like ILI visits, not laboratory-confirmed influenza 5
- Focuses on syndrome detection rather than case gathering 5
Clinical Context
Active surveillance systems like the one described have demonstrated superior timeliness, detecting cases 7-8 weeks earlier than passive electronic disease reporting systems. 3 This approach enables rapid case ascertainment and strain identification, making it particularly valuable during emerging outbreaks or pandemic situations. 2, 3
Answer: A - Active