RE: parvo........killer
When my chocolate lab was 12 weeks old he got parvo...and he had had all of his shots too.
He was listless and had the runs (sorry to be gross, but it looked like chocolate milk).
The most important thing is keeping them hydrated. We ended up rushing him to the local "emergency room" for pets...he did survive, but only after a week stay at the vet's.
Good luck.