No you can't get parvo from a cat scratch. It's transmitted by contact with an infected parvo stool or can be caused from a reaction to parvo vaccine. If the stools are solid it's o.k. to go back to a normal diet. Once a pup has recovered from parvo it's immune to further episodes of it. The incubation period is about 7 days. For pups showing symptoms of parvo I would give one drop of Lugol'sIodine daily. Vitamin C is also beneficial to give to a parvo pup. Give several times a day because vitamin c washes out of the system fairly rapidly. I'm not a fan of combination vaccines. It bombards the immune system and lowers it. I only gave single shots when I was breeding. One parvo and one distemper and that's all I gave. Give Pedialyte to drink if the pup has diarrhea. Can be added to the drinking water or if the pup is refusing to drink syringe it down their throat.