Bird Flu, also known as avian influenza, is a virus carried primarily by birds, as well as certain mammals. There are actually 144 different strands of the virus, with varying intensity in symptoms and contagiousness. However, one strand in particular, H5N1, has caused widespread panic, as it has not only been transmitted to humans, but caused a mortality rate of over 50%.

The details of bird flu are very technical and somewhat difficult to understand to the average person. More in-depth information is available in ebook 2 of "A Guide to Bird Flu and How to Avoid Catching It." Influenza, in general, is grouped into one of three categories: A, B, and C. Avian influenza is considered type A. Under category A, there are 16 H subtypes and 9 N subtypes. There are basically two variations of the virus among all the subtypes, a low pathogenic form, which is rather mild, and a high pathogenic form, which is considerably more harsh. To date, only H5 and H7 variations of the virus are highly pathogenic.

What does all of that mean in English? Although there are numerous strands of the virus, only a couple have ever been known to seriously harm humans. Although bird flu was first identified in the early 1900's, the strand to cause the most concern recently, H5N1, first came to pass in 1997 in Hong Kong. In the current outbreak, there have been 100 people infected with the virus in Asia, and over half did not survive.

Bird Flu has symptoms typical of regular flu strands. These include, fever, sore throat, cough, conjunctivitis, and possibly pneumonia, in severe cases. However, with H5N1, these symptoms become severe and often lead to death.

The major concern with H5N1 is the possibility of the virus starting a pandemic. This may occur when a new virus emerges, it causes serious illness in humans, and is easily spread among humans. With bird flu, the first two conditions have already been met. H5N1 is a new virus to humans, although it has previously been found in poultry; it also causes serious illness in humans, as it has led to the death of over half of the 100 people infected by it. However, at this point, the third criteria has not been met. Bird flu is predominantly passed from fowl to humans, not human to human. Many people believe it is just a matter of time before the virus mutates to the point human transmission is possible. At that point, it will spread like wildfire throughout the world.