Avian influenza (bird flu) is an infection that occurs naturally amongst wild birds.

The virus is carried in their intestines, but it usually does not make the birds sick. However, avian influenza is very contagious and can make some domesticated birds, including chickens, ducks, and turkeys, very sick and kill them (WHO 2006).

Concerns have been raised regarding the high possibility of bird flu mutating into a highly contagious human flu.

The influenza A viruses associated with the three major 20th century human pandemics all appear to have genetic components originating from bird viruses.

The 1918 H1N1 virus killed 20 to 40 million people worldwide and the 1957 H2N2 and 1968 H3N2 viruses were far less lethal, but still were each responsible for more than 1 million deaths (WHO 2006).

Now, in 2006, all eyes are focused on H5N1, which is more commonly known as bird flu.

The World Health Organisation (2006) warns that it will only be a matter of time before the Avian Flu, which has been spreading throughout parts of Asia and Europe in the past months, develops into a global pandemic: "Extrapolating these figures to the world population, a gross estimate of the impact of the next pandemic calls for 1-2 billion cases of flu, 5-12.5 million cases of severe illness, and 1.5-3.5 million deaths worldwide!".