I hold my breath when walking past mentally challenged people bc I fear it’s contagious

Ever since I was a kid, mentally challenged people were in my schools and when they would walk by me in the hall, I would hold my breath as long as possible. I lived in constant fear that they were contagious and I would be mentally challenged if I breathed their air. This habit continued through college and it wasn’t until I confessed to my wife that I stopped…. But I still find myself doing it till this day. (M 41)