WHO says Russian authorities report no plague case after a laboratory worker's death in the Irkutsk region

7 October 2026

A woman who worked at a laboratory in Russia's Irkutsk oblast in Siberia died, and the World Health Organization said the authorities were examining whether pneumonic plague caused her death.
WHO spokesperson Christian Lindmeier told reporters in Geneva that her workplace was an institute studying dangerous pathogens, including plague, in a part of Siberia where plague occurs naturally in wild animals.
On 7 October, WHO Director-General Tedros Adhanom Ghebreyesus said Russian regulators had told WHO there was no evidence pneumonic plague played a part in her death and that no pathogens had been detected; about 200 of her contacts were placed in quarantine.
Plague is caused by the bacterium Yersinia pestis, usually found in small mammals and their fleas.
Pneumonic plague occurs when the bacteria infect the lungs and can spread from person to person through respiratory particles.
WHO says this form can be fatal within 18 to 24 hours of onset if untreated, but common antibiotics for enterobacteria can cure it if given early.
Nearly 4,000 plague cases and 423 deaths were reported across 10 countries between 2019 and 2025, most of them in the Democratic Republic of the Congo and Madagascar.