Sad to say, there are probably some crazy bio-warfare guys sitting someplace watching this, and thinking:
"SARS is not really too terrifying. But, if we created a germ that was a little more deadly, and spread a little more easily, we could clearly cause chaos in any nation on Earth. Sure, long term it might blowback and affect our friends and family also -- but we're crazy bio-warfare guys. And we don't care."
You wouldn't even need biowar scientists to create this; there are some who are dumb enough to cook up bad things just for the hell of it. An Australian scientist did this several years back -- he crossed smallpox with mousepox. Check out the book "Demon In The Freezer" by Richard Preston. Regards.