What is Avian influenza?
'''Avian influenza''' ('''bird flu''', or '''avian flu'''), is an [[illness]] caused by a [[virus]]. The virus, called ''influenza A'' or ''type A'', usually lives in [[bird]]s. Sometimes it [[infection|infects]] [[mammal]]s, like [[human]]s. There are many types of influenza A. It was first found in a bird in [[Italy]] in 1878. Most types have weak [[symptom]]s like [[conjunctivitis]] and afluenza-like symptoms. Also [[breathing problems]], like the [[common cold]]. It often [[mutate]]s. But some types kill birds, and a few kill humans and other mammals. One type of bird flu, called ''Spanish flu'', killed 50 to 100 million people<ref name=Knobler>{{cite book | editor=Knobler S, Mack A, Mahmoud A, Lemon S | title=The Threat of Pandemic Influenza: Are We Ready? Workshop Summary (2005) | chapter=1: The Story of Influenza | pages=60–61 | chapter-url=http://darwin.nap.edu/books/0309095042/html/60.html | publisher=The National Academies Press | location=Washington, D.C. }}{{Dead link|date=January 2021 |bot=InternetArchiveBot |fix-attempted=yes }}</ref> in 1918/1920. Another type, called ''Asian Flu'' killed one million in 1957. Another, called ''Hong Kong Flu'', killed one million people in 1968. A subtype, called ''H5N1'', killed six people in [[Hong Kong]] in 1997, but did not kill again until 2003, this time in [[China]]. Until the middle of 2005, it was primarily found in southeast [[Asia]] but since then has spread to parts of [[Africa]] and [[Europe]]. It has killed tens of millions of birds and resulted in the slaughter of hundreds of millions of other birds to limit its spread. So far it is mostly a bird disease and rarely infects humans. The concern about H5N1 is that it is constantly evolving at a very fast rate. It might create a human flu [[pandemic]]. Governments around the world are spending money to deal with this problem: studying H5N1, creating [[Vaccine|vaccines]], conducting pandemic practice exercises, stockpiling useful flu medication, and many other activities. == 2020s spread == === Unit