The vamprie disease is a sickness plauging the vampires of the world. The elder vampires have fought its effects for centuries, and it is now beginning to effect the younger vampires faster than normal. There is a prison under morganville that is full of vampires who are in the final stages of the disease. They have lost sight and mind, and are beginning to slow down and die.
The cure was found in the end. It was the blood of Bishop, Amelie's father. His blood cells were different from Myrnin's when looked under a microscope. Mixed together it was shown to cure Myrnin's blood.