Just my thoughts on the situation, I HIGHLY doubt that your puppy got parvo from CATS. It just doesn't happen...parvo is a very stable virus in the environment and can live in the ground for upwards of 9 months. Since your dog was not vaccinated, he could have picked it up from anywhere. Cats don't get the same strain of parvo that dogs get..don't blame the kitties! lol
Thank you for the response. We brought him home today after 12 days in the hospital. He is doing a lot better since the second transfusion. He is eating now and seems more comfortable at home. The vet believes the virus was contracted from the MANY stray cats in the neighborhood who are being fed by a neighbor who I am sure thinks she is doing the right thing, but has no idea of the problems she is creating for others. We and others have battled flea infestations, massive amounts of feces left by them and now this. We assume Leroy ate some infected feces left by one or more of them. A bad reaction to his first vaccine left him with seizures and we were afraid of continuing the series. A horrible mistake on our part! One worry for his health just created another. While not completely out of the woods yet, we are hopeful he will make a full recovery.
If you google parvovirus, you will be able to read about how it affects the dog. It specifically targets rapidly dividing cells (the bone marrow and enterocytes). The bone marrow is the source for all blood cells and therefore, the body needs more time to regenerate them. In the meantime, supportive care like fluids and antibiotics (to treat secondary bacterial infections) are used until the bone marrow can regenerate cells.
Like any virus, there are no antibiotics that will get rid of it. You have to treat the animal with aggressive supportive care and hope that it outlasts the virus. There are going to be ups and downs as the dog's immune system tries to fight off the infection.
Do you know where your dog was infected? Did you purchase or adopt an infected dog? I ask because parvo is a very hardy virus and can live in the environment for months. So think contact with viral laden feces that may be in the yard.