R.B.
my son is a "carrier" of strep. He will have it but doesn't get the symptoms but will pass them on to the rest of the family. He doesn't get the sore throat, the puss bags or the fever.... he will get scarletina. That's how we know he has it. We are never how sure how long he has had it.. but long enough to where he gets scalretina. Even with it in his charts and ped being well aware of it they will not treat him until he shows symptoms... those symptoms are always scarletina.
He has never had any problems with his heart and I have never had a dr express concern about it either. My guess is that he would have to have it for a LONG time before you have to worry. I can't even tell you how many times he has had scarletina... atleast once ( if not twice) a year since he was two.
* just in case you don't know.. scarletina/ scarlet fever is from untreated strep*