Not the way it works. Of all possible mutations, only a tiny percentage, probably far below 1%, make the disease more deadly to humans. Were this not the case, such a rapidly mutating disease would have wiped out the human race long ago. In actual fact, a truly virulent form comes along only every few decades.
I've read that the flu virus is actually descended from an intestinal virus affecting dinosaurs. It's not easy for a virus with this history to affect the human respiratory system.
BTW, one theory for the 90% to 95% loss of population in North America during the 16th century is the spread of swine flu and anthrax from De Soto's pigs to the human population.
So, what are you saying, we shouldn’t be concerned? At all? I’m not saying panic, just saying it might be man-made. This virus has mutated in a very deadly way at least twice before, 1918 and 1976.