Originally Posted by DominicMazoch:
People who get rabies have foam coming out of the mouth. Rabid=Madness! That is the history of the word "foamer" I heard in the Houston area
You heard correctly. Despite other definitions of the term's evolution that may come up via the Internet and other sources, the currently accepted heritage/usage of the term (dating back at least 30-or-so years when I first heard it) relates to a rabid dog's foaming at the mouth.