[Radical Edward]

The thing I wonder about this, is that the Bird Flu is dangerous to humans because it infects lower down in the trachea, however that is also what makes it difficult to travel from human to human, because it cannot cause the same sorts of physiological responses. If on the other hand it did mutate and attach to proteins higher in the trachea, it would become more infectious, but lose much of its lethality. Of course there is the possibility of it having multiple surface proteins which allow it to attach to both, but that is pretty unlikely.