The elephants of Zoba Gash Barka, Eritrea: part 4. Cholelithiasis in a wild African elephant (Loxodonta africana).

A 4.0-kg cholelith was found within the abdominal cavity of a dead wild African elephant (Loxodonta africana) in Eritrea. Analysis of this cholelith by histochemistry, electron microscopy, electrospray mass spectroscopy, and energy-dispersive x-ray spectroscopy revealed it was composed of bile alcohols but no calcium, bilirubin, or cholesterol. Bacteria were also found in the cholelith. Similar, but smaller, bile stones have been identified previously in other wild African elephants and an excavated mammoth (Mammuthus columbi). Choleliths have been reported only once in a captive Asian elephant (Elephas maximus). Elephants, along with hyraxes (Procavia capensis) and manatees (Trichechus manatus), are unique among mammals in producing only bile alcohols and no bile acids, which may predispose them to cholelithiasis, particularly in association with bacterial infection. Dietary factors may also play an important role in cholelith formation.