Number of confirmed swine flu cases could be "tip of iceberg".
O'Dowd
Adrian
A
Charatan
Fred
F
D004196:Disease Outbreaks / Q000706:statistics & numerical data*; D014943:Global Health; D006801:Humans; D053118:Influenza A Virus, H1N1 Subtype; D007251:Influenza, Human / Q000453:epidemiology*