What if it is a bio weapon and they don’t know where it is? Like Sum of All Fears. So they are locking people down so they can track it down. (Could be multiple weapons).
I was thinking that if the wuflu is an escaped (or purposely released) bioweapon, it seems to not be virulent enough to be a finished product. Thus, imho, it was either accidentally or prematurely released, and thus the fatality rate is pretty pathetic for a bio weapon. Maybe the heathen Chinee released it early due to urgency. Or accidental, before it was finished. That is my pet theory.
But an additional thought occurred to me; perhaps there are long term sequelae connected with the infection that have not manifested in many people yet.