Most recent examples of Plague have been seen in the immigrants entering from the Southern border. Several of the children that showed up in this country over the last two years have had plague.
Now it is unlikely that this particular case came from them. There is no reason not to use this case to highlight the serious health risks associated with unregulated immigration. After all we should never let a good crisis go to waste.
According to the CDC, there have been 14 cases over the last three years (2012, 2013, 2014, no data for 2015, yet). Of those 14, there has been one death. It's easily treatable with antibiotics if discovered soon enough.
Note, don't get me wrong, I know there are more diseases coming across our border from the south, but the Plague is simply not one of them.