Quote Originally Posted by asplundii View Post
Diseases tend to be very host specific and when they make the jump 99.999% of the time it is a dead end jump because the new host is not a fit environment for the disease.
You fail to mention one thing because it doesn't help your point at all.

The definition of a good host for a disease is one that lives long enough to spread the disease. Diseases can dead end because they are far too deadly to continue on in the new species. Normally this is not a problem but modern travel allows disease to spread world wide where in the past a single civilation would have been destroyed. There are real concerns for people here, just not with this strain of flu. There are examples in modern history of species being eliminated from disease even when the best and brightest minds tried to prevent it. The bananas we eat today are not the bananas our grandparents ate. Their bananas are all dead. We only have wine today because the roots of new world grapes are resistant to the disease we spread that nearly wiped out old world grapes.