Our vet said the Parvo virus lives for up to 8 months in warm climates. But if the weather cools off it can live longer. But not 7 years. But I have been reading a lot about Parvo. and it is everywhere. Even places where you wouldn't think it would be. It can be carried by animals that would get in the vomit or poo of the contaminated animal, such as birds, mice, ground squirrels, rabbits. And where we live there are wild dogs or dogs that have owners that let them roam. And most of them don't have their shots. so there is no guarantee about Parvo. My vet said if you run over the feces or vomit with your car. you can carry the Parvo virus home on your tires. We didn't know but just before our puppy came down with Pavo, our next door neighbor's puppy died of it. So it could have been carried to him. They have a dog that jumps the fence all of the time. That dog gets in our yard all of the time.