Iceberg Phenomenon

Icebarg of disease

• Disease in a community may be compared with an iceberg.
• The floating tip of the iceberg represents what the physian sees in the community, i.e. clinical cases (Diagnosed case, symptomatic case or clinically apparent case).
• It includes sub-clinical cases & carriers
• The vast submerged portion of the iceberg represents the hidden mass of disease, i.e. latent, inapparent, presymptomatic and undiagnosed cases and carriers in the community.
• The “waterline” represents the demarcation between apparent and inapparent disease.
• Epidemiologist is concerned with Hidden portion of iceberg whereas clinician is concerned with tip of iceberg.
• Screening is done for Hidden portion of iceberg whereas diagnosis is done for tip of iceberg.
• Iceberg phenomenon of disease is not shown by rabies, tetanus and measles.
• The clinician concerned only with the tip of iceberg, i.e symptomatic cases that are seen in clinical treatment, this can result in inaccurate view of the nature and causes of a disease results because the minority of the cases are studied (hidden cases :-. submerged portion of ice berg is not studied) → Clinician’s Fallacy.

In some disease, a great deal of subclinical infection occurs –

• Rubella
• Polio
• Japanese encephalitis
• Influenza
• Mumps
• Hepatitis A and B
• Diphtheria