(Bloomberg Businessweek) -- In the evolutionary arms race between humanity and the microbes, the bugs are making a comeback. Yes, we’ve conquered diseases such as smallpox and polio, and deaths from communicable diseases have been falling worldwide. But since 1970, more than 1,500 new pathogens have been discovered, according to the World Health Organization, and “epidemics in the 21st century are spreading faster and farther than e...