I got it from my niece. We never figured out where she got it from. I was visiting when she was sick and did not have the full diagnosis yet. Because of my lesser immune system I was more prone to get it. No one else in her family got it and they were able to take the prescribed antibiotics to prevent the infection. I took the preventative but I still ended up with a case of it. Trust me when I say you don't want to get it. I stayed home from work the prescribed time for being contagious and no one at work got it. But it took me several weeks to shake it totally.