Influenza

**Definition:** Any disease of the respiratory system, caused by an infection with influenza virus. These diseases are characterised by fever, cough, headache, myalgia, arthralgia, or malaise. Transmission is by inhalation of infected respiratory secretions. Confirmation is by identification of influenza virus from a nasopharyngeal, nose, or throat swab.

**Long definition:** Influenza (the flu) is a contagious respiratory illness caused by influenza viruses. Some people will develop complications as a result of the flu, some of which includes (a) cough, fever, shortness of breath by pneumonia, (b) wheezing, fever, chest discomfort by bronchitis, (c) ear pain, hearing loss, vomiting by sinus and ear infections, (d) neurological deterioration, seizures, coma by encephalopathy, and (e) dyspnea, shock by myocarditis.