The presentation of influenza virus infection varies, but it usually includes many of the following signs and symptoms:

Fever Sore throat Myalgias Frontal or retro-orbital headache Nasal discharge Weakness and severe fatigue Cough and other respiratory symptoms Tachycardia Red, watery eyes

Avian influenza (H5N1) is rare in humans in developed countries

Influenza is a viral infection that attacks your respiratory system — your nose, throat and lungs. Influenza, commonly called the flu, is not the same as stomach "flu" viruses that cause diarrhea and vomiting.

For most people, influenza resolves on its own, but sometimes,