Cheetahs are being threatened by a deadly disease called amyloid A amyloidosis, or AA amyloidosis. The illness kills up to 70 percent of the cats in captivity, making breeding efforts difficult.
AA amyloidosis resembles mad cow disease. A misfolded version of a protein converts normal proteins into abnormal ones, until large deposits of damaging protein build up in tissues -- the spleen and liver in the case of AA amyloidosis, the brain and central nervous system for mad cow disease.
AA amyloidosis is not caused by a bacteria or virus, but it can likely spread from animal to animal like an infectious disease. Biologists have had difficulty, however, figuring out how the disease moves from cat to cat.