It will all come back to them in the end, and ya just dont wanna get me started on how people dont care for animals and respect them, ESPECIALLY pit bulls,but enough about those dumbasses you should be focusing on baby. when you got her you should have immediately taken her to a vet and checked for heart worms, fleas, mites etc. no matter what the ppl you bought her from said. heart worms are very common for pups. but anywho, my cousins dog had parvo disease and they actually got him cured! VERY expensive though. So if you cannot do this, you need to give her as much love and attention as possible, always hydrating her, and there is actually an all natural formula treatment you can get them, its on sale at this site,
http://dogparvosymptoms.net/parvo-shop/ , and it help with symptoms and has cured many cases. But before you buy this i would advise you go to a vet first just to find out EXACTLY whats wrong and if there is anything else your wittle pup needs to have done.
good luck and keep posting updates on how shes doing!