Definition
Iceberg phenomenon means the clinically apparent (visible) cases are only the “tip” of the iceberg, while a larger proportion of disease remains hidden below the surface as:
– subclinical disease
– undiagnosed disease
– mild disease not presenting to health services
Components of the iceberg
Tip (visible):
– diagnosed cases
– hospital admissions
– notified cases
Submerged (hidden):
– asymptomatic or pre-symptomatic cases
– unreported cases
– undetected cases in the community
Public health implications
- True burden is underestimated if we rely only on facility data.
- Surveillance and screening are needed to detect hidden cases.
- Programme planning and resource allocation must consider undetected disease.
- Health education and risk communication should target apparently “healthy” people too.
Examples
- TB: latent infection and subclinical cases vs notified TB
- Diabetes/HTN: asymptomatic disease vs diagnosed cases
- COVID-19: asymptomatic infections vs detected cases (especially early waves)
Mini-Exam Box
5-line answer (Short note)
Iceberg phenomenon describes how the visible, clinically detected cases are only a small part of total disease burden; most cases remain hidden as subclinical/undiagnosed disease. It implies facility data underestimates true burden. Therefore, surveillance, screening and community surveys are important. Planning must consider hidden morbidity. Examples include HTN/diabetes and latent TB.
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