A vet CANNOT! confirm Parvo over the phone! Further to that immunity is irrelevant since only pups generally become symptomatic.I am from Pakistan. And the reason why vet will be visiting my home tomorrow is because the Vet is my friend. And he took all the details on phone call. And confirmed that it is Parvo. Moreover last time when I visited him for vaccination, Bella and Maxie both kept on Vomiting because it was their first time in the Car. So being my friend the Dr said he himself will be visiting my home with his staff, feed & observe the puppies at home for a while.
Supportive care may pull some pups through but since the virus can cause long term damage a vet needs to be involved. The stool you photographed looks more like worms or gastro issue. Parvo produces nearly black stool that has a pudding almost tar like look due to the amount of blood. It also has a distinct and unforgettable smell.
I keep responding to this thread because misinformation about Parvo could kill someone's pup.
If you suspect your pup has Parvo it needs to be SEEN by a vet immediately! Early diagnosis and care greatly improves a pups odds.