RT Book, Section A1 Cohen, Yehuda Z. A1 Dolin, Raphael A2 Kasper, Dennis L. A2 Fauci, Anthony S. SR Print(0) ID 1141411168 T1 INFLUENZA T2 Harrison's Infectious Diseases, 3e YR 2017 FD 2017 PB McGraw-Hill Education PP New York, NY SN 9781259835971 LK accessbiomedicalscience.mhmedical.com/content.aspx?aid=1141411168 RD 2024/10/09 AB Influenza is an acute respiratory illness caused by infection with influenza viruses. The illness affects the upper and/or lower respiratory tract and is often accompanied by systemic signs and symptoms such as fever, headache, myalgia, and weakness. Outbreaks of illness of variable extent and severity occur nearly every year. Such outbreaks result in significant morbidity rates in the general population and in increased mortality rates among certain high-risk patients, mainly as a result of pulmonary complications.