I am on the road, attending the ScienceOnline 2009 conference this weekend, so we have another classic favorite from Pondering Pikaia (which is where you can also find my updates on this week’s conference). I decided to make cheetahs a theme for the week (between reproductive issues, habitat loss, and prion disease, the damn things can’t catch a break) and resurrected this post from last May.

Cheetahs have posed a challenge to zoos and conservation programs for decades, because they are extremely fickle breeders and have almost no genetic diversity. Another obstacle is that this species is prone to developing AA amyloidosis, a protein folding disorder. Animals with this condition develop plaque and aggregates of misfolded protein fibers in the brain, and they eventually die. The disease is similar to mad cow disease and Alzheimers, both of which also feature the faulty protein folding and amyloid build-up characteristic of prion disorders.

While brain plaque doesn’t seem to be a likely vector for transmitting a disease between individuals, a study recently published in the Proceedings of the National Academy of Sciences (Zhang et al. 2008) reports that amyloidosis is actually contagious and highly transmissible between animals. It appears that the amyloid proteins are present in an afflicted animal’s feces, and if another cheetah is exposed to the feces they can also develop the disease. The title of this post was intended to be punny: the data doesn’t suggest that cheetahs regularly engange in true coprophagy, meaning the intentional consumption of fecal matter. Cheetahs apparently do ingest each other’s feces, however, albeit indirectly. The amyloids from the fecal matter could contaminate the zoo exhibit by getting into the ground, food, or water, or they could be transferred from animal to animal during grooming. The new findings could have implications for the future of cheetah conservation programs. The citation is below, or you can see this New Scientist article about the research for a summary.

Zhang, B., Y. Une, X. Fun, J. Yan, F. Ge, J. Yao, J. Sawashita, M. Mori, H. Tomozawa, F. Kametani, and K. Higuchi. 2008. Fecal transmission of AA amyloidosis in the cheetah contributes to high incidence of disease. Proceedings of the National Academy of Sciences 105: 7283-7268.