When Daisy was diagnosed, my vet said that there are several studies going on about why this happens in cats and not in dogs or other "domestic" animals - cows, etc.

There is speculation that because cats have a rather strange immune system things might go wrong when combined with some vaccines being "live" - meaning some cells of the actual disease are in the injection and the body builds up immunity to those live cells. I believe there also was some speculation on whether some combination of shots caused the problem.

So I'm sure many bright minds and caring hearts are working on this problem for our furry friends! I just hope they hurry!