What would emerge would be a disease as deadly as avian influenza, which currently has a case fatality rate of over 50%, but that moves as easily as seasonal influenza does from person to person,
What this virus can't do now is move easily from person to person. We worry that it could develop this characteristic of human-to-human transmission.
Bird flu is a disease among animals; it's very difficult for this virus to move from poultry into humans. Our concern is that it will change in a way that will allow it to easily move between humans, and that will trigger a pandemic.