You can't. That's why no one from SARS countries should be allowed in until they have this under control in their own country.
it's not like our government has the power to quarantine people while they are in another country...
But they do have the power to revoke Visas into our country.
But they won't do that. But why not? Because there's big money at stake. Surely we can't alienate foreigners we depend on for our global economy. Money talks, right?
But that's fine. We'll still let them in, and when they get Americans sick, we'll just quarantine them. After all, its just the rights of Americans at stake and foreigners and their money are so much more important than that.
Isn't globalism great?