D.A.
Well I recently had this problem with my 3 year old as well. I think that she was going around the house and picking it up all over again. Even though she is three, she still likes to put things into her mouth, even if only by habit. The only thing that worked for me was going around the house with a can of Lysol, scrubbing and disinfecting everything which is a daunting task, I know. But my advice to you would be to try the Lysol before moving on to thinking it is something more.