Saiga antelope

A male saiga antelope on the steppes of Russia. Credit: Getty

Infection

Mass die-off of rare antelope linked to heat

High temperatures and humidity made a harmless bacteria lethal.

Climatic conditions transformed a usually harmless bacterial infection into a dangerous outbreak that killed more than 60% of the world’s saiga antelope.

More than 200,000 saiga antelope (Saiga tatarica tatarica) in Kazakhstan died of a virulent infection over a 3-week period in May 2015. Richard Kock at the Royal Veterinary College in London and his colleagues conducted post-mortem examinations of 33 animals and identified a bacterium (Pasteurella multocida), which caused extensive internal bleeding, as the culprit.

The bacterium does not typically harm healthy saiga, which suggested that an environmental factor might have made the microbe more dangerous. The team analysed weather data from 1979 to the mid-2010s, a period that included three mass die-offs of saiga — in 1981, 1988 and 2015. They found that the outbreaks were linked to relatively high daily temperatures and humidity levels.

Careful management is needed to protect the remaining populations of this critically endangered species, especially in the face of climate change, the authors say.