H5N1 Human death in NanJing. 3rd December 07, page 1

I guess the good news is that unless someone handles infected birds directly there really isn't much danger to the general population yet. Avian Influenza H5N1 has yet to alter its Hemagglutinin proteins and/or Neuraminidase enzymes in such a way as to allow human to human infection. However, in comparison to other serotypes of Influenza A it shares most of its genome with other known avian viruses, which appear to cause the most damage when humans are infected. Case in point, when the surface glycoproteins and genome of H1N1 antigenically shifted back in 1918 it of course caused a pandemic, but also shared a majority of its genome with avian viruses as well. This shows that should H5N1 retain a majority of genes associated with avian viruses upon antigenic shift it will more than likely cause a large scale human infection. Should it drift to the point where it retains a distinct majority of genes shared with humans then we will probably not see the large scale infection rates that could otherwise be expected.

On a larger scale the most interesting thing about H5N1 is that it's the only Avian influenza virus to alter its RNA polymerase enzyme from Glutamic Acid into Amino Acid, which in turn gives it that ability to interfer with human Lysine bases. Unlike other serotypes of Influenza A, which tend to infect only one species per mutation, H5N1 has the ability to cross the species barrier. In fact, most of the Orthomyxoviridae family of viruses share either Lysine or Glutamic Acid in common, making H5N1 the odd one out, and why it may become more of a problem than previously thought.

As ChiKeyMonKey pointed out the virus dwells in the upper respiratory tract in humans. This is essentially because there are only some areas in the body that will allow H5N1 to bind with cellular surface receptors, and in birds these receptors share binding factors with a sugar known as Galactose found primarily in the brain of birds. On the other hand in humans these receptors are few and far between, so much so that the only place the are located at in the human body are around the Aveoli in the lungs. Once they bind, the virus becomes hard to expel because the Aveoli are are so deep in lung tissue that they do not easily allow a normal cough to expel the virus.

As for the medications...

Oseltamivir (Tamiflu) is a Neuraminidase enzyme inhibitor that breaks down the process of Neuraminidase cleavage with sialic acid and thus prevents viral budding from a host cell. Now, the best medication would be something that essentially disallows the virus from binding with the cellular receptors. However, with Influenza this becomes virtually impossible as fast mutating RNA viruses like Influenza tend to alter their surface glycoprotein structure enough to negate the effects of Entry Inhibitor medications. Currently, and sadly, only Tamiflu and Relenza can do anything against the virus as they do not block surface binding.