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. An even greater slaughter of animals occurred in the spring of 2003 when a new H7N7 virus appeared in poultry farms in the Netherlands, Belgium, and Germany. This virus infected eighty-two people and killed one, and it also infected pigs. So public health authorities killed nearly thirty million poultry and some swine.
