You sound like a liberal plant. As a typical disseminator of false information you pick out one thread to destroy the whole cloth. It maybe a syntax error, but he does not exactly say that Leprosy is a highly contagious disease. He says that certain disease have long been eradicated, and that the American people should know that illegal are now bringing them back. And that is true.
Do some research on leprosy. It is nothing like TB or polio, and there is precisely zero chance of a leprosy "epidemic" in the U.S. The handful of cases (currently about a hundred a year) are almost entirely (quite possibly absolutely entirely) in immigrants from countries where it is endemic and their immediate families, and nearly all of them caught it where they came from, after long term close exposure to other infected people -- not here (it takes 4-6 years after infection for symptoms to appear).
I am hardly a liberal when it comes to immigration issues. I think any adult-size person seen crossing our border illegally should be shot on sight, and illegal immigrants who are found already here deported within 24 hours. But if political figures promoting a crackdown on illegal immigration get a reputation as ignorant scaremongers, it will hinder, not help, the cause.