In the absence of suddenly appearing sores, you'll probably never know. Now what do you want to do about it?
Assuming the lady ever even had that outbreak (hey, my brother's a biologist too; he's way smart, but I defer to him on matters of marine ecology, not who's had which kind of cooties and when), she did owe it to you to fess up. This does not absolve you from failing to think about, ask about, or take responsibility for avoiding infection yourself, though, does it? It takes two to tango, tangle, or transmit, after all.
If you don't like games, don't "intimate" things — ask them. If you want to know if you got infected, get a blood test. If you want the girl, call her. I don't see where any of these are mutually exclusive.