I have dealt with Parvo a lot lately. In a matter of 2 months I had pulled 6 puppies, 4 of which died of Parvo. The disease is just plain awful and mean. When the pups would not eat I did several things:

I mixed dry with soft food.
I offered them Gerber Stage 2 Lamb baby food.
I offered them turkey lunch meat.
I made little meal with Yogurt, rice, raw egg, and ground beef (either cooked or not will work).

When it was close to the end for the pups that did not make it, I syringe fed them the babyfood and also some yogurt.

Good luck and I hope your lil' pup gets well soon. Please keep us posted. By the way, WELCOME TO PET TALK.