The animal is passed over a sick person, and then split open and examined for clues to the disease.

ECONOMIST: The birth of the mega cuy

Current methods for detecting disease in livestock are slow and open to abuse, because they rely upon farmers or vets reporting sick animals, says Marcus Doherr of the Institute of Animal Neurology at the University of Bern in Switzerland.

ECONOMIST: MONITOR

"If my daughter is sick or I have to pay school fees and this animal comes to our beach, then I have to catch it and kill it because people like the meat, " argues Ashietey, who says he has done precisely that on two occasions.

BBC: volunteers pulling a turtle to safety