Wow, I'd never heard of such things until it happened to my doggy 5 years ago. And I've had dogs most of my adult life. When she's gone, I'll have 6 little boxes on my shelf. Wonder if it's kind of new? Oddly, it took a while to discover what was wrong with her, had to take her to a University vet school, get a transfusion to give them time to diagnose. And my vet is good, but said it doesn't usually happen so young, and, to her knowledge, always with a booster. Occurs to me that this is sarcasm, if so, got me :). With my previous dogs, I stopped regular vet checks as they aged. No pushback from vet, and county never hunted me down for rabies tax. Wish we could use that excuse for our kids.