I did some looking around and from what I am reading, first you are right they do carry it but you would still have to mostly ingest it. The other way appears to be scratches and bites given by the rat. I did not see one saying 100% yes to lready having a cut there..so that part I am uncertain about. With how small of a scratch it sounds like I am betti g it was closed up enough by now to protect you just in case. Sounds like to me it would be an unlikely incident.