Carl Zimmer reports on some of the work being done to understand the extreme die-offs of saiga antelopes in Central Asia: “More Than Half of Entire Species of Saigas Gone in Mysterious Die-Off”.
Once individual saigas became ill, they typically died within hours. Entire herds were quickly wiped out. “This is really not biologically normal,” Dr. Kock said.
Necropsies revealed internal bleeding, and blood testing showed that the saigas suffered massive infections of bacteria called Pasteurella multocida and Clostridium perfringens.
These species are normally harmless constituents of the microbiomes of many animals. From time to time, however, they can explode into deadly infections.
I find it disquieting that a “normally harmless constituent” of the microbiome might go on an unpredictable killing spree under slightly unusual temperature or rainfall conditions. The death toll from this year’s event is 150,000 saigas.