IRKUTSK, Russia — Russian health authorities have placed nearly 200 people under medical observation after an employee of an anti-plague research institute in Siberia died following a severe respiratory illness.
The woman worked at the Irkutsk Anti-Plague Research Institute of Siberia and the Far East, near the city of Irkutsk.
Russian media identified her as Daria Shipilova, a laboratory worker in her late 20s.
Early reports said she may have been exposed while handling dangerous biological material at the institute.
One account, reported by independent Russian media, said she told medical workers that a test tube containing live bacteria had broken while she was working.
Russian federal health authorities have since disputed key parts of that account.
On Sunday, October 4, 2026, Rospotrebnadzor, Russia’s public-health and consumer-protection agency, said expanded testing had found no microorganisms in the woman’s samples associated with her work at the institute.
It said her diagnosis was “pneumonia of unknown etiology.”
The agency also said no accident involving pathogenic microorganisms had been recorded at the institute.
That leaves the cause of the woman’s illness and death unresolved publicly, despite statements from other Russian officials that referred specifically to plague.
Nearly 200 People Monitored
The woman became seriously ill late last month and was admitted to a hospital in Shelekhov, a town outside Irkutsk.
She developed severe pneumonia, was placed on a ventilator, and died on October 2, according to Russian media reports.
Authorities identified people who had been in contact with her and placed them under medical observation.
At least 197 people were being monitored, including more than 100 in hospital wards, according to The Moscow Times.
Igor Kobzev, governor of the Irkutsk region, said on Friday that none of the people being monitored had shown signs of illness and that laboratory tests had been negative.
“All identified contact persons have been placed under medical observation,” Kobzev said.
The Shelekhov district hospital was also placed under quarantine as health officials assessed the risk.
Rospotrebnadzor chief Anna Popova travelled to the region and met local officials as authorities introduced measures aimed at containing any possible spread.
The federal agency said on Sunday that conditions in Irkutsk and Shelekhov remained “stable.”
Conflicting Accounts Over Plague
The uncertainty has been heightened by statements from officials outside the Irkutsk region.
Alexei Tsydenov, the head of neighbouring Buryatia, said earlier that the woman had died from plague, citing information from Rospotrebnadzor and regional authorities.
He said she had not recently visited Buryatia and sought to reassure residents that no plague outbreak had been detected there.
“There are no plague outbreaks in the republic, including in areas bordering Mongolia,” Tsydenov wrote on social media.
Irkutsk officials initially used the broader description of a “particularly dangerous infection” rather than naming plague.
Russian and independent regional outlets subsequently reported that the employee might have broken a test tube containing live bacteria while collecting laboratory samples.
That account has not been confirmed by the institute or by Rospotrebnadzor.
The federal agency’s latest statement moves in the opposite direction, saying expanded laboratory testing failed to identify microorganisms connected to the employee’s professional work.
The CNN report on the incident also noted the discrepancy between accounts of a laboratory accident and the Russian government’s description of the illness as pneumonia of unknown origin.
Institute Specialises in Dangerous Pathogens
The Irkutsk institute is part of Russia’s network of specialised facilities devoted to monitoring and researching plague and other highly dangerous infectious diseases.
Such institutes conduct surveillance in regions where plague bacteria can circulate naturally among rodents and fleas and also analyse biological samples for dangerous pathogens.
Plague is caused by the bacterium Yersinia pestis.
The World Health Organisation says humans can become infected through flea bites, contact with infected tissue or materials, or inhalation of respiratory particles from someone with pneumonic plague.
Pneumonic plague affects the lungs and can spread between people through respiratory particles. It can progress rapidly but is treatable with antibiotics when detected early, according to the WHO.
There is currently no official confirmation from Russian federal health authorities that Yersinia pestis caused the Irkutsk employee’s illness.
Authorities Seek to Reassure Residents
Reports of the death prompted concern in Irkutsk and surrounding communities.
Local authorities cancelled some public events, while reports circulated that hospitals were restricting access and that additional precautions had been introduced at workplaces in the area.
Officials have repeatedly urged residents not to panic.
Rospotrebnadzor said its response included a package of sanitary and epidemiological measures and maintained that the regional public-health situation was under control.
No illness linked to the case had been reported among those being monitored as of the latest official statements.
