Do you really believe the USA governments health agency carries an US citizen into the US if it was not perfectly safe? In what paranoia 1984 world do you live?
Is that the same USA governements health agency that deliberately withheld treatment and information about syphilis from infected patients to see what would happen, or a different one? That was a while ago so probably not. But perhaps it was the one that exposes its scientists to anthrax? Or avian influenza? Or leaves smallpox samples chill in a random warehouse?
It's perfectly safe guys, please move along!