The most probable and the greatest likely imminent threat to the United States and the rest of the world is a severe bird flu pandemic. There are an estimated four influenza (flu) pandemics each century. The last severe one was in 1918. This killed about five percent of the world's population. Five percent of today's U.S. population would be approximately fifteen million people (three hundred million of the world's pop.). Influenza mutates extremely rapidly even compared to other viruses. Influenza also can share genes with other strains of influenza. This makes it very possible or even probable that the deadly persistent bird flu (the H5N1 strain) currently sweeping the wild and domestic bird populations will eventually be able to be easily transmitted from human to human.
Influenza has a history of being one of the most contagious of viral infections. The H5N1 strain of influenza is known to have infected 240 humans. Of these, 140 have died for a death rate of 58%. If it becomes easily contagious between humans, no one knows what the death rate will be. It could easily be very high.
Modern medicine will not be capable of curing such an infection.
This story is about a small group trying to survive in the social upheaval of a severe pandemic. I believe such chaos is possible. (Mike Stones MD)