I did a bit more investigation into this and I think I have found an answer. The culprit is a disease called Tuleremia, or "Rabbit Fever". An easy way to tell if a rabbit has this disease is to look at the liver during cleaning. If there are white spots on the liver, the rabbit is no good to eat, and you should wash your hands very thoroughly ASAP. It can be transmitted from rabbits to people either by eating the meat, or through a cut in your hand during cleaning. From what I have read, temperature has nothing to do with this disease.