There is a product called parvaid here is one site that carries it:
Buy Parvaid, A Cost-Effective, Natural Home Parvo Treatment Remedy
I can not speak from personal experience as I've never used it but I have heard from others who swear by it on one of my breeding sites. It might be worth it to try and hopefully if she does contract it, it will help lesson the severity. Good luck, I hope she doesn't get it at all. I hate Parvo!