Tuberculosis was almost wiped in this country, and people coming into the country illegally (from Asia) have brought a particularly virulent strain with them that challeneges a new form of treatment, since all known forms fail.
The same goes for the "Black Syph", a form of syphillis also from Aisa that resists current treatments.
But, let's just keep welcoming these people with open arms!
If they had come in legally (which they couldn't!) these diseases would have been discovered and the carriers would have been turned away. But since we really don't care, once they're here we take them in and let them spread their inflictions on others.