Passive Surveillance
The Ministry of Health is employing passive surveillance (Answer C) when it gathers routine influenza case reports from hospitals, health centers, and laboratories during the winter season.
Understanding the Surveillance Type
The scenario describes a system where healthcare facilities report flu cases to the Ministry of Health through established channels. This is the hallmark of passive surveillance, where:
- Healthcare providers initiate reports as part of routine practice, rather than surveillance personnel actively seeking out cases 1
- Data flows from healthcare facilities to state/national health departments through established reporting channels, as described in CDC's influenza surveillance framework 1
- The system relies on existing healthcare infrastructure and medical record documentation for sustainable, cost-effective long-term monitoring 1
Why Not the Other Options
Not Sentinel Surveillance (Option A)
- Sentinel surveillance involves selected reporting sites or populations to monitor disease trends, not comprehensive case gathering from all hospitals and healthcare facilities 1
- The CDC uses sentinel surveillance through specific networks like the Outpatient ILI Surveillance Network (ILINet), which involves approximately 110 WHO collaborating laboratories and 240 National Respiratory and Enteric Virus Surveillance System laboratories 2
- The question describes gathering data from all hospitals, health centers, and labs—not selected sites
Not Active Surveillance (Option B)
- Active surveillance requires deliberate, organized data collection by trained personnel who actively seek out cases, rather than waiting for routine reports 3
- In active surveillance, surveillance teams proactively contact healthcare facilities and search for cases, which is not described in this scenario 3
- The question describes passive receipt of data, not active case-finding efforts
Not Syndromic Surveillance (Option D)
- Syndromic surveillance monitors symptom patterns or syndromes before laboratory confirmation, typically through automated data systems 1, 3
- The CDC uses syndromic surveillance for influenza-like illness (ILI) monitoring, which tracks symptom patterns rather than confirmed diagnoses 1
- The question describes detecting "flu cases" (confirmed diagnoses) from labs and healthcare facilities, not monitoring symptom patterns
Clinical Context
Passive surveillance is the backbone of most national notifiable disease systems because it is sustainable and cost-effective for long-term monitoring 1, 4. While it has limitations including underreporting and delays compared to active surveillance 5, it remains the practical choice for routine seasonal influenza monitoring across an entire country's healthcare system.