I read a study that linked it to the distemper (I think) vaccine.
I read that there is a possible correlation to distemper vaccine as well, but I think it was due to the drastic rise in pano cases after the vaccine started.
SBD Posejpal's Leyna, HCTs 6/16/2010
SBD Posejpal's Hades, 5/9/12
At the rainbow bridge:
Zappa 12/27/00-1/23/12 You are my heart, my soul, and my best friend. You will be with me always.
Zeus 5/9/12-8/13/12 You taught me strength. Run free.