Bird flu was first identified in the early 1900s and has since spread worldwide. Also known as avian influenza, this virus has caused considerable concern due to the mutation of a particular strain of the disease. Although this virus previously only infected birds and other types of animals, namely pigs, since 1997, it has also been known to infect humans.
The strain of the disease to cause so much concern is H5N1. These are simply numbers and letters that represent the subtype of this particular strain, 1 of 144 influenza subtypes. Not only has the virus caused an epidemic in poultry, but it has recently been feared to be leading to a pandemic, or worldwide epidemic, in humans.
While the virus was first identified in humans in 1997, it was not until 2004 that the spread became of great concern. At that time, a major outbreak occurred in Vietnam and Thailand, which spread to ten countries and regions of Asia within weeks and caused the death of 23 people. Within three months the outbreak was contained after the slaughter of tens of millions of potentially infected birds. However, the damage was already done and the virus had spread across Asia to lead to...