The difference between H7N9 and H5N1, is that H5N1 kills chickens very rapidly, so it is easy to identify where the infected flocks of chickens are. H7N9 doesn't make the chicken sick, so it has been difficult to pinpoint where the infected chickens are.

There's always the danger when you have influenzas that infect chickens, that when you have the close quarters of chickens spreading from one to another and occasionally a human coming into close contact, that there will be the jumping of species from a chicken to a human. This is not something new.

All it takes is a flock of infected geese or ducks landing near a chicken farm, and because they are so close in these open pens, it can go like fire.

Even the pandemic flu of 1918 only killed one to two percent of the people who were infected.

Whooping cough is not a mild disease. Whooping cough, before the vaccination, could make you very, very sick. First of all, there was a chance you could die from it - small chance, not a big chance. You would be coughing and coughing. It wouldn't last for a few days, like a cold.

A crane standing amidst a flock of chickens