Avian Influenza
Bird flu is a general term that describes any form of influenza that can infect birds (avians). According to the Center for Disease Control, most forms of bird flu are not dangerous, even for birds. In fact, many wild birds carry around strains of avian influenza in their intestines without suffering any adverse effects. Some domesticated birds, however, are more susceptible to the effects of avian influenza (due to a less robust immune system caused by inbreeding and being raised in controlled environments). These susceptible birds include turkeys, chickens and ducks and can become infected via exposure to contaminated saliva, feces and nasal secretions.
Mutation and Human Infection
Avian influenza is a type A influenza virus, which means that it comes from the same class of flu viruses that typically infect humans. Avian influenza, on the other hand, is named because it typically only infects birds, not humans. Like all flu viruses, however, this virus has a tendency to spontaneously mutate, changing its genetic code. In some cases these mutated avian flu viruses gain the ability to infect humans, allowing the virus to be transmitted from birds to the human population. These cross-over viruses can be particularly dangerous because they represent a different kind of flu and human immune systems may not have developed immunity against these new flu strains.
Routes of Human Infection
According to the Mayo Clinic, people can become infected with bird flu if they are in close contact with diseased birds. People can also contract bird flu by touching surfaces that have been contaminated with the feces, saliva, or nasal secretions of birds that have been infected. Although it is possible for bird flu to spread directly from one person to the next, the virus is not transmitted easily between humans. Thus, the people at greatest risk of developing bird flu are those that work closely with birds or who have extensive contact with bird-infested areas.
