At least 12,000 critically endangered saiga antelopes (Saiga tatarica) have been found dead in Kazakhstan in the past two weeks, victims of a mysterious epidemic. The deaths represent about 15 percent of the species' worldwide population.

Saiga antelopes used to number above one million, but the breakup of the Soviet Union led to rampant poaching throughout the species' range and 95 percent of the animals were killed off. Just 81,000 of the antelopes remained in five isolated populations in Russia, Kazakhstan, Uzbekistan and Mongolia. Until this outbreak, the Kazakh population numbered 26,000 animals, almost half of which have now died.

So what caused the outbreak? According to tests by the Kazakh  government, the antelopes died of pasteurellosis, an infection that afflicts the lungs. According to a release by the IUCN, "Pasteurellosis is caused by a bacterium that lives naturally in healthy individuals, but can cause acute illness and rapid death if the animal's immune system is compromised, either by another infection, poisoning, stress or malnutrition."

Olga Pereladova, director of the World Wildlife Fund's Central Asia Program, told the Daily Telegraph that the animals might have been malnourished following an unusually cold winter and by an overly hot spring, which may have contributed to the spread of the disease.

Serik Imanukulov, a Kazakh official who heads the department of sanitary and epidemiology in the area, told the AFP news service that the infection may have now passed, and predicts that no more deaths will occur. "We can say the outbreak of the infection has passed and come to a close," Imanukulov said. "I do not think there will be new cases of mass deaths among the saiga at present."

A spokesperson for the Kazakh Emergencies Ministry told the Telegraph that the dead saiga are being burned to prevent further spread of the disease.

Photo: Saiga antelope, via Wikipedia