Standing Bear writes: "Also, if one only read the up to now current news about this, its fatality rate of over fifty percent of those contracting it would mean a global catastrophe of over 3,000,000,000 dead."
I believe that is impossible. First, not all of the population will be infected. The 1918 pandemic infected about a quarter of the population. Second, influenza symptoms are quick, unlike something like AIDS. An influenza that kills half the victims will die out. It is self-quenching. But diseases rapidly evolve to become less virulent, and less dangerous to the carrier. (A disease that does not do that goes extinct.) The danger point will come when more patients survive long enough to spread the disease. I think roughly 5% or 10% would be the cut-off point, when more than one person would be infected by each carrier before the carrier dies or recovers. The bubonic plague was spread by rats and mice, not people. It does not kill the carriers, as far as I know. So even though it killed as many as half the people in some places it did not go extinct. It still exists. A repeat of the 1918 virus, assuming no advanced medical care or anti-viral medication is available, would kill roughly 150 million people. That is more or less the situation today: the vast majority of the people in world today have no better medical care than they did in 1918. In fact health care has gotten worse in many third world countries. In first world countries many fewer would die at first until we run out of hospital beds, equipment, antibiotics (to combat the bacteria that invades tissue weakened by virus), anti-viral medicine and so on. Overall, I think the worst-case scenarios run from 100 million to 600 million worldwide, but not as high as 3 billion. In another 30 to 60 years, we will probably develop much better methods of detecting diseases, and designing and fabricating vaccines. We will be able to stop an influenza epidemic in real time. That is, we will learn to make 100 million doses of vaccine in a few weeks with something like bioengineered yeast. Now it takes months or years, using fertilized eggs. I doubt that infectious diseases will ever disappear, but they will become a minor problem, not a threat to civilization. - Jed
