Influenza pandemics generally infect from 15 to 40 percent of a population; any influenza virus infecting that many people and killing a significant percentage would be beyond a nightmare. In recent years public health authorities have at least twice identified a new virus infecting humans but successfully prevented it from adapting to man. To prevent the 1997 Hong Kong virus, which killed six of eighteen people infected, from adapting to people, public health authorities had every single chicken then in Hong Kong, 1.2 million of them, slaughtered.
