Influenza virus transmission.

An interesting blog post from 2006 by Revere on some aspects of what H5N1 virulence (in terms of disease severity), transmission and preconceptions. 

Do we put too much stock in believing that recently emerged viruses eventually settle in to their new hosts, seeking a perfect balance between virus replication, transmission and host mortality? 

In other words, do viruses adapt over time so that originally severe infection outcomes (like pneumonia) become mild illnesses (like the common cold or just feeling a it crook). 

There may be some parallels to be drawn with H7N9 as we continue down its path. 

Or perhaps H7N9 has been adapting to humans for longer than we think?