[janeroe]

> Because we get a lot of travelers through our country who may otherwise spread TB here if we made no effort to control it outside of the country

A dozen of vaccines and a proof (from the doctors certified by the US officials) that you have no contagious diseases (including TB) is a prerequisite to get any US visa. The only way to bring TB to the US, I presume, is to jump over the fence at the border.

[throwway120385]

Or to contract it on your way to the US through one of the many stops you will make along the way.