My Puppie Is 8 Months Old And Has Started Acting Like He Has Parvo. Isn't He Too Old To Get Parvo?

No, my parvo paranoid vet wants my puppies back for another shot at 9 months. None of the shots it had in the past may have taken. Here is a link giving a better and more authoritative explanation than I can, Canine Parvovirus, What you should know about

The good news is that an 8 month old has far more dog to resist the virus and much more likely to survive. That wouldn't keep me from seeking immediate attention for a lethargic dog with a foul smelling diarrhea.

No dog is too old for parvo,and vaccines are never 100 percent.Most vaccines work,but I've seen dogs and cats still become infected with viruses and diseases,even after being vaccinated.There is a test which takes about 10 minutes,and will tell you if parvo is what your dog has.The test is not too expensive either.I hope it not parvo,no animal deserves to go through that kind of agony.Let us know what happens.