More than 60 staff at a Russian plague research facility have been isolated following the death of a laboratory worker, sources told RFE/RL's Siberia.Realities, and the United States said it was monitoring reports of a suspected case of pneumonic plague.
Darya Shipilova, a 28-year-old laboratory technician at the Irkutsk Anti-Plague Research Institute of Siberia and the Far East, was hospitalized on September 29 and died at a hospital early on October 2, according to news reports and sources.
Independent Siberian news outlet Lyudi Baikala (People of Baikal) reported that Shipilova accidentally broke a test tube containing pneumonic-plague bacteria on September 25 while working at the institute. Russian authorities have not publicly confirmed that account.
Rospotrebnadzor, Russia's consumer and public-health watchdog, said Shipilova had been diagnosed with "pneumonia of unknown etiology," meaning that its cause was unknown. The agency said additional testing was conducted because of her professional activities but did not detect microorganisms associated with her work.
Rospotrebnadzor also said no accidents involving pathogenic microorganisms had been recorded at the institute.
Asked about the matter before leaving on a trip to Europe on October 5, US Secretary of State Marco Rubio said the US was "watching and monitoring it closely."
"I don't think it's cause for alarm, but it is cause for focus and a cause to just keep an eye on," Rubio said.
In a Telegram post on October 5, regional Governor Igor Kobzev said the "sanitary and epidemiological situation in Irkutsk" and the nearby district where Shipilova had been hospitalized "is currently stable." He added that no new cases of institute employees seeking medical care had been reported in recent days.
At the same time, authorities have imposed precautionary measures. About 200 people who may have had contact with Shipilova were placed under medical observation or isolation, many of them at hospitals in the area, according to media reports.
Staff at the anti-plague institute have been confined to the facility since October 2, sleeping on floors and chairs while awaiting test results, two independent sources among employees and their relatives told Siberia.Realities. The sources spoke on condition of anonymity due to the sensitivity of the situation and fears of repercussions.
"They locked everyone inside for isolation starting Friday (October 2), more than 60 people," a relative of an institute employee said, adding that "by Saturday (October 3), not a single positive test had been found. They're sleeping there on the floor and on chairs. There are, of course, no beds. Relatives were allowed to bring food through the checkpoint."
Former colleagues of Shipilova said the institute has strict biological-safety measures, including plague vaccinations for interns.
Quarantine has also been reported at two Irkutsk hospitals and a maternity hospital, with visitors barred and patients unable to leave for up to six days.
On October 3, the Irkutsk Aluminum Plant in the nearby town of Shelekhov introduced a mask mandate.
The measures have fueled speculation because Russian officials initially avoided publicly referring to plague, while local and independent reports described a possible laboratory accident involving Yersinia pestis, the bacterium that causes plague.
The pneumonic form of Yersinia pestis, a bacterium that normally circulates among wild rodents and fleas, affects the lungs and can spread from person to person through respiratory droplets during close contact. The disease can progress rapidly, but modern antibiotics can be highly effective if treatment is begun promptly.
There is currently no publicly confirmed evidence of transmission among residents of Irkutsk.
US Monitoring Situation
Hours before Rubio spoke, a State Department spokesperson told RFE/RL said the department was "aware of reports of a fatal case of suspected pneumonic plague in Irkutsk Oblast, Russia," and was "monitoring the situation closely with the CDC (the US Centers For Disease Control And Prevention) and our other interagency partners."
The State Department urged Russian authorities to "share accurate information quickly and openly," while noting that plague is treatable with commonly available antibiotics, particularly when treatment begins early.
The reports have prompted concern among some US lawmakers and former officials, including over Russia's history of biological-weapons research. There is no public evidence that the Irkutsk laboratory was developing plague as a weapon or that the worker's death was connected to an offensive biological-weapons program.
Republican Representative Don Bacon, a senior member of the House Armed Services Committee, spoke of longstanding Russian allegations that US-supported laboratories in Ukraine were involved in biological-weapons research.
"I remember hearing from anti-Ukraine voices about their so-called bio labs. It was Russian disinformation ops at their best. But in reality it is Russia with the bio labs," Bacon wrote on social media.
Russia has long accused Washington and Kyiv of running biological-weapons facilities in Ukraine, allegations both governments reject and independent investigations have found no evidence to support.
The Soviet Union maintained a large offensive biological-weapons program during the Cold War, despite being a party to the 1972 Biological Weapons Convention. Defectors and subsequent investigations documented military research involving pathogens including plague, as well as efforts to develop antibiotic-resistant strains.
In an April 2025 report on compliance with arms control commitments, the State Department said the United States "assesses that Russia maintains an offensive biological warfare program and is in violation of its obligations" under the Biological Weapons Convention.
Russia denies that, saying such facilities are aimed at developing defenses against pathogens.
