Pooped.
captive cheetahs are besieged by amyloid fibrils and (bottom panels, respectively) in their liver.
Yumi A / National Academy of Sciences, PNAS (08)
Although rapid famous, cheetahs can not seem to overcome a deadly disease called amyloid (AA) amyloidosis. The disease kills up to 70% of cats in captivity and has frustrated breeding efforts. In a new study, the researchers provide the first convincing evidence that could explain how the disease is transmitted.
AA amyloidosis resembles mad cow. Like mad cow, a misfolded version of a protein - in this case amyloid A - converts the normal proteins into abnormal, a process that snowballed into large deposits of damaging proteins in tissues such as the spleen and liver. (The protein mad cow did most of its damage in the brain and central nervous system.) The animals often die of renal failure and the incidence of AA amyloidosis has climbed from 20% to 70% cheetahs in captivity since the 1980s
AA amyloidosis is caused by a bacteria or virus, but there is reason to suspect that it can spread from animal to animal as a infectious disease. The mad cow and scrapie - a related disease in sheep - appear to be contagious. When captive cheetahs are kept in small enclosures close, AA amyloidosis strikes younger animals and with more severity, a finding that confirms the hypothesis of contagion. However, biologists have been hard to understand how the disease moves from cat to cat.
To examine potential routes of transmission, Keiichi Higuchi, a biologist at Shinshu University in Matsumoto, Japan, and colleagues isolated the AA protein from livers of infected animals. Of the protein, the researchers were able to develop a fluorescent marker, in other experiments, picked up the AA protein in the feces of diseased cheetahs. The discovery supports earlier studies that had marked feces as a possible route of infection for similar diseases in deer and mice. Furthermore, the AA protein in the feces was more transmissible and more effective in inducing the disease in mice that the protein isolated from the liver, probably because of its small size and greater instability, researchers report online today in Proceedings of the national Academy of sciences .
It is still unclear how captive cheetahs come into contact with the feces of another. Higuchi's team suspects that this may occur when cats lick their fur during grooming or when they eat food that has touched the contaminated soil. Based on their findings, the researchers suggest that zoos or breeding colonies in captivity can limit the spread of AA amyloidosis eliminating feces promptly or keeping animal food separate areas that have come into contact with feces. "These results provide possible measures to save the cheetah from extinction," says Higuchi. There are only about 12,500 cheetahs living on the planet today, he notes, so any cheetah death is a blow for survival of the species.
Sarah Durant, a conservation biologist at the Zoological Society of London and the Wildlife conservation Society in the United States, said limiting the spread of AA amyloidosis in captive animals is a good strategy. Although the disease is unlikely to affect the cheetahs release, she said that the conquest in captivity could raise awareness about the plight of wild cheetahs.
Related Sites
- More about cheetah diseases
- More information about cheetah conservation
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