There's a fatal disease in Central and South America called Chagas, and the way it's spread is NASTY:  Blood-sucking insects called 'kissing bugs' crawl into your bed, FEED ON YOUR FACE, then move their BOWELS.  Then when you scratch the bite, you wipe their parasite-filled feces into your eyes or mouth.  Like I said:  Nasty.  Chagas can cause heart failure, but it doesn't look like it's headed to North America.  Still, be careful when you travel.