Avian Influenza (Bird Flu) is a highly contagious and almost always fatal disease that was started in southeast asia in 2003. It is formed by the influenza virus type A. Influenza viruses are classified into 3 types. Type A is the strongest and most dangerous one of all. It can spread the most and is found in humans, birds, liveslock and several other mammals. Type B can spread only between humans. Type C is almost harmless and cannot be spreaded.
H5N1(The virus that crutes the Bird Flu) is a subtype of the type A influenza virus.H and N stands for Haemagglutinin and Neuraminidase, which are kinds of proteins. H5N1 is 5 parts of Haemagglutinin combined with 1 part of Neuraminidase. The virus can stay infected in something for a long time, and that will increase the chance for it to spread. The virus can travel to far distances by migrating birds, and infect furthur regions. The Type A influenza virus can spread rapidly and can mutate every 2-3years. The disease's mutation is the worst fear. It will become more contagious and more deadly. In 1918-1919, there was an outbreak of a type A influenza virus subtype H1N1 called "Spanish Flu" . It killed 50 million people worldwide.