Internet-based monitoring of influenza-like illness (ILI) in the general population of the Netherlands during the 2003–2004 influenza season

Table 2 Questions asked about symptoms of ILI

-No symptoms?	Cough?
-Running nose?	Headache?
-Sore throat?	Chest pain?
-Muscle pain?	Diarrhea?
-Abdominal pain?	Cold shivers?
-Nausea	Irritated eyes?
-Sudden fever? (No/yes/don't know)
-How high was the fever? (37C/between 37C and 40C, in steps of 0.5 degree)

Definition of ILI: Fever >38C, that started suddenly, plus headache or muscle pain, plus at least one of the respiratory symptom: running nose/coughing/sore throat/chest pain

ISSN: 1471-2458