he was vaccinated against it. The vaccines can be rendered ineffective because of maternal immunity, from what I hear. I suppose that may have been the case with this dog.
when i was a kid, my dog got parvo but my mom caught it early and he was in the doggie hospital for a week but he recovered and lived to be a ripe old age of 14
Parvo is a nightmare. My wife and I do dog rescues (mostly Boston Terriers and Collies) and some of the group homes get Parvo infestations. (Heartworm is another big problem) It is sad there are so many dogs out there people do not take care of.