Yes there is 'treatment' and that is the individual must start denying the obsession, no not deny as in I don't have it, but deny in not complying with it. Studies have shown that each time an obsession is not 'obeyed' new neuropathways begin to form and will begin to reverse the imbalance that brought the obsession on. I am living proof that this is a better way to beat such a problem versus taking drugs for it.
And yes, they often happen after Strep. They think that anorexia nervosa may also begin with Strep.
One of my daughters had that horrible affliction. I do not recollect whether or not there was a strep infection involved. I had serial strep infections in college and was plagued with the most horrible nightmares. I can't help but wonder as I read this whether there was a connection.
Very interesting. A moral theologian or a classical philosopher would say that virtue is a habit. The more you practice a particularly virtue, the more habitual it becomes, until the effort becomes easier than it was at first. Your explanation about developing new neural pathways fits into what I have read about recent brain research, and it would help explain why this ancient wisdom should be true.