What is Influenza?
{{Infobox disease |Name=Influenza |Image=EM of influenza virus.jpg |Caption=Influenza virus, magnified approximately 100,000 times |Width=226 |DiseasesDB=6791 |ICD10={{ICD10|J|10||j|09}}, {{ICD10|J|11||j|09}} |ICD9={{ICD9|487}} |MedlinePlus=000080 |eMedicineSubj=med |eMedicineTopic=1170 |eMedicine_mult={{eMedicine2|ped|3006}} |MeshID=D007251 }} '''Influenza''', better known as the '''flu''' and sometimes called the '''grippe''', is a common childhood illness, but is not as common among adults. It is not limited to humans, most mammals and many birds can also catch influenza. It is caused by several different viruses, termed influenza viruses A, B, C, and D. == Flu transmission and symptoms == Human influenza can pass from one person to another very easily. It is most commonly spread by the microscopic droplets of [[mucus]] and fluid that are sent into the air when the sick person [[cough]]s or [[sneeze]]s. [[Symptom]]s include cough, sore throat, [[muscle]] aches and pains, [[fever]], headache, and rarely [[vomit]]ing and [[diarrhoea|diarrhea]]. Influenza can also lead to other diseases, such as [[pneumonia]]. This makes it especially dangerous to young children and elderly people. Although there is no cure for influenza, [[antiviral drug]]s can be used to treat the illness so it is not as severe and does not last as long. Influenza [[Vaccine|vaccines]] are available worldwide, and are quite effective. They are changed each year as the virus changes. The influenza season runs from late fall to spring because most people catch it in the winter months. When there are more cases of influenza than expected, it will sometimes be called an [[epidemic]]. When there are a large number of cases of the same type of influenza all over the world, it is often called a [[pandemic]]. == History == The virus is ancient. It has infected humans for centuries.<ref>Morens D.M, Taubenberger J.K, Folkers G.K, Fauci A.S. 2010. Pandemic influenza's 500th anniversary. ''Clinical Infectious Diseases''. '''51''' (12): 1442–1444. doi