In May 2015, uncommonly large numbers of saiga began to die from a mysterious illness suspected to be pasteurellosis.
Herd fatality is 100% once infected, with an estimated 40% of the species' total population already dead.
Decided that climate change and stormy spring weather may have transformed harmless bacteria, carried by the saigas, into lethal pathogens.
Pasteurella multocida, a bacterium, was determined to be the cause of death. The bacterium occurs in the antelopes and is normally harmless; the reason for the change in behavior of the bacterium is unknown.
Now scientists and researchers believe the unusually warm and wet uncontrolled environmental variables caused the bacterium to enter the bloodstream and become poisonous. Blood poisoning is the likely cause of the most recent deaths.
The saigas were particularly vulnerable at calving.