I would bet it's safe to assume she has notified her other clients, which is obviously the responsible thing to do. You do realize your mail will blow up asking who she is, right?  

Since you didn't say what the STD is, I'll presume it's not a death sentence. She has obviously been treated for it since she went in for medical attention and received a diagnosis.  

Is it ok for her to advertise and see clients after being treated for an STD and notifying her clients who may or may not be infected? Or should she now end her career?

If she has been treated, my answer is yes.  The average sex worker probably practices safe sex more diligently than the average Saturday night pick-up.  

Basically you've come on to post about a provider being responsible by notifying you but thankfully you didn't name her, how embarrassing when all she did was let you know she had an STD which you MAY or MAY NOT have contracted.  

I do not see how effective this warning is unless she does not practice safely. And safe practices are not a guarantee, obviously. Those safe practices simply reduce the risk.  

Be careful out there!!