(VIDEO) Russian Lab Worker Dies of Suspected Plague in Siberia as Nearly 200 Placed Under Medical Observation

MOSCOW — A young worker at a Russian plague research institute in Siberia has died of a severe pneumonia that one regional leader said may have been plague, prompting quarantines, mask requirements and medical monitoring of nearly 200 people who had contact with her.

Russian health authorities insisted Monday that the situation in the Irkutsk region is stable and said tests found no sign of the dangerous microorganisms the woman worked with. But conflicting statements from officials, along with reports in independent Russian media of a laboratory accident, have fueled concern at home and abroad.

The World Health Organization said it was aware of reports that a laboratory worker had died of "severe pneumonia" but that "no cause of death has been officially confirmed." The U.S. Centers for Disease Control and Prevention said it was monitoring the situation.

What officials have said

The woman worked at the Irkutsk Anti-Plague Research Institute of Siberia and the Far East, a facility in the town of Shelekhov, near the city of Irkutsk, that studies plague and other highly dangerous infections.

She was hospitalized Tuesday with symptoms of severe pneumonia and died Thursday, according to Russian media reports. Independent regional outlets identified her as Darya Shipilova, a 28-year-old laboratory technician. Officials have not publicly named her.

Russia's consumer health watchdog, Rospotrebnadzor, said the employee had been diagnosed with "pneumonia of unknown etiology," meaning the cause had not been determined. The agency said it had expanded testing of samples from the patient.

Irkutsk Gov. Igor Kobzev, in his first public comments on the case on Sunday, did not mention plague. He described the woman only as an employee of the institute and relayed the findings of health authorities.

"No microorganisms linked to the employee's professional duties were detected in samples taken from the patient," Kobzev said.

"No reports of infectious diseases have been recorded among institute staff over the past 10 days. All individuals who had contact with the patient have been identified, examined, and placed under medical observation involving daily laboratory testing," he said.

Rospotrebnadzor said in a separate statement that "the sanitary and epidemiological situation in the Irkutsk region, the cities of Irkutsk and Shelekhov is stable."

According to the Interfax news agency, a special commission at the institute and Rospotrebnadzor concluded that no emergency or security breach had occurred at the facility.

Kobzev said an extraordinary meeting of the regional anti-epidemic commission was held with the participation of Anna Popova, Russia's chief sanitary doctor, who traveled to the region.

Conflicting accounts

The first public suggestion that the death was linked to plague came from Alexei Tsydenov, the head of the neighboring Republic of Buryatia.

In a post on his Telegram channel on Saturday, Tsydenov said a woman in the Irkutsk region had "died, maybe of the plague." Russian media reported that he initially described the death as caused by plague before adding the word "maybe."

Tsydenov also sought to reassure residents of Buryatia, saying authorities had confirmed that the woman had not traveled to the republic.

Some independent Russian outlets and social media accounts reported that the technician became ill after a test tube containing Yersinia pestis, the bacterium that causes plague, broke at the institute in late September. Those reports have not been independently verified, and Russian authorities have pushed back against claims that her illness resulted from a laboratory incident.

Quarantines and masks

Despite official assurances, several precautionary measures have been put in place in the region.

Russian and Ukrainian media reported that at least one hospital, including the district hospital in Shelekhov where the woman was treated, was placed under quarantine, with some reports saying as many as five medical facilities had been affected. Mask requirements were introduced at some sites.

Measures were also reported at the Irkutsk Aluminum Plant in Shelekhov. The plant's director, Artem Fominykh, urged calm and said that "there are many rumors and conflicting reports circulating."

Russian media cited officials as saying nearly 200 people who had been in contact with the woman had been placed under precautionary medical observation. Officials said those under observation showed no signs of illness.

A dangerous but treatable disease

Plague is caused by the bacterium Yersinia pestis and is best known for the Black Death, which killed tens of millions of people in Europe in the 14th century.

The disease still occurs naturally in parts of the world, including Central Asia, Africa and the Americas, where it circulates among rodents and is usually spread to humans through flea bites.

There are three main forms. Bubonic plague, the most common, causes swollen lymph nodes. Septicemic plague affects the bloodstream. Pneumonic plague, which infects the lungs, is the most dangerous form and the only one that can spread directly from person to person through respiratory droplets.

Pneumonic plague can be fatal within days if untreated, but it can be cured with common antibiotics if diagnosed and treated early. People who have close contact with a patient are typically given preventive antibiotics and monitored.

Human cases are rare in Russia but do occur. Natural plague hot spots exist in mountainous regions of southern Siberia, including the Altai region, where a herder contracted bubonic plague in 2015 after handling a marmot.

Role of the institute

The Irkutsk Anti-Plague Research Institute is part of Russia's network of facilities dating back to the Soviet era that monitor and study plague and other dangerous infections. It tracks natural plague outbreaks across Siberia and the Far East and works with live pathogens in specialized laboratories.

Laboratory-acquired infections are rare but have occurred around the world, including at high-security facilities. Such incidents typically prompt investigations into safety procedures and contact tracing to prevent further spread.

Health authorities have not said when final test results on the cause of the woman's death will be released. Those under observation are undergoing daily laboratory testing, according to the governor.

The WHO and the CDC have not announced any travel restrictions or recommendations related to the case.

For now, Russian officials maintain that there is no threat to the public. But the lack of a confirmed cause of death, combined with contradictory statements from regional leaders, has left many questions unanswered about what happened inside the Siberian laboratory.