Russia Calls Second Plague Case Reports False as WHO, EU and U.S. Press for Answers on Irkutsk Lab Death

Russia on Wednesday dismissed reports of a second suspected plague case at a Siberian research institute as false, even as the World Health Organization, the European Union and the United States said they still lack the information needed to judge the risk. Kremlin spokesman Dmitry Peskov said most media reporting on the situation was false and urged Russians to rely only on statements from Rospotrebnadzor, the country's public health watchdog, Euronews reported.

At the center of the dispute is the death of Darya Shipilova, a 28-year-old employee of the Irkutsk Anti-Plague Research Institute of Siberia and the Far East, who died Oct. 2 in the town of Shelekhov near Irkutsk. Russian authorities have attributed her death to pneumonia of undetermined cause. No laboratory has publicly confirmed plague in her case or in the reported second employee.

For U.S. readers, health officials describe the direct risk as very small. The larger question is how quickly governments share data about suspected outbreaks that begin in places where dangerous bacteria circulate naturally in wild animals, and what outside scientists can conclude when that data is missing.

A Standoff Over One Lab Worker's Death

WHO Director-General Tedros Adhanom Ghebreyesus asked Moscow on Wednesday to clarify media reports of a second institute employee with pneumonia of unclear origin. "Timely, complete and transparent information-sharing in line with the International Health Regulations is critical," Tedros said, according to Euronews.

WHO's Maria Van Kerkhove said the agency still does not know what caused the first death, Al Jazeera reported. The U.S. State Department said it had formally requested more information from Moscow, while Peskov said he had no knowledge of an official U.S. request.

In Brussels, European Commission health spokesperson Eva Hrncirova said Thursday the bloc cannot yet weigh the threat. "We don't have enough information to assess the epidemiological situation," she said, according to a Euronews report on the EU response. The EU's Health Security Committee met Wednesday but made no decisions because of the lack of reliable information, and the Commission said it could reconvene at short notice.

Russian Test Results and WHO's Risk Rating

Rospotrebnadzor said Shipilova had been vaccinated against the infections she worked with, that nearly 5,000 laboratory tests found no dangerous pathogens, and that it sees no epidemic risk. It said more than 90% of the people who had contact with her have completed medical monitoring. Early media reports put the number placed under observation at about 200, and Russian authorities have not published a detailed updated count.

At a briefing in Geneva on Tuesday, WHO spokesperson Christian Lindmeier said all of the workers' contacts had been identified, and none had shown symptoms, according to the UN Geneva briefing record. WHO's initial assessment rated the risk moderate to low for Irkutsk, low for Russia as a whole, and very low for the WHO European region. The agency said it would update that assessment as more information arrives.

WHO said its monitoring system picked up media reports of the death on Oct. 2 and that it contacted Russian authorities the next day under the International Health Regulations. Those regulations require countries to share timely information about events that could have international public health implications.

The test results and contact figures are claims made by Russian authorities and relayed by WHO, not independent findings. If plague is eventually confirmed, it would be Russia's first confirmed plague infection since 2016, according to Euronews. No public evidence supports claims that the illness involved a weapon, and President Donald Trump told reporters Wednesday that U.S. officials did not think so.

Plague's Wild Reservoir in Siberia

The case drew immediate attention because of where it happened. Lindmeier noted that the institute studies dangerous pathogens "in a part of Siberia where plague occurs naturally in wild animals."

Plague is caused by the bacterium Yersinia pestis, which usually lives in small mammals and their fleas. People most often catch the bubonic form from flea bites. The pneumonic form, which infects the lungs, can spread between people through respiratory particles and can be fatal within 18 to 24 hours without treatment, though common antibiotics are effective when given early, according to WHO.

Natural plague cycles are not unique to Siberia — the bacterium also persists in wild rodent populations in parts of the western United States, which is why health and wildlife agencies there warn hikers, campers and pet owners about fleas and sick or dead rodents.

That wildlife link is a central reason scientists say detailed information matters. Without knowing whether the worker's illness came from a laboratory exposure, a natural source or neither — the central unanswered question — outside experts cannot judge whether wider surveillance of local animals or people is warranted.

Risk to Americans Remains Low

The Centers for Disease Control and Prevention has described the risk to the United States as extremely low. CDC Director Erica Schwartz said the agency is working with the departments of Homeland Security, State and Defense to monitor travelers from the region, and a CDC health station at New York's John F. Kennedy International Airport can screen arrivals, Al Jazeera reported. In a separate statement, the CDC said there is "no indication of a broader threat to the United States."

About 200 people a year travel from the Siberian region to the United States, a Health and Human Services spokesperson told Reuters, and direct flights between the two countries have been suspended since 2022. Most Americans do not need to take any action. Anyone returning from Siberia who develops sudden fever, cough or chest pain should seek medical care and mention their travel.

In plague-endemic parts of the American West, the usual precautions still apply: avoid handling sick or dead rodents, use flea control on pets and report unusual rodent die-offs to local health or wildlife officials.

Several questions remain open, including the worker's confirmed cause of death, whether a second employee is ill, and exactly how many people remain under observation. Trump said Wednesday that U.S. officials expected to have an update soon. WHO said it will revise its risk assessment as information comes in, and Nature World News will update this story as health agencies report new findings.

Developing Story Timeline

Oct. 8: The European Commission says it lacks enough information to assess the risk after an EU Health Security Committee meeting ended without decisions.

Oct. 7: The Kremlin calls reports of a second case false, WHO's Tedros asks Russia for clarification, and Rospotrebnadzor reports nearly 5,000 negative tests.

Oct. 6: WHO rates the risk moderate to low for Irkutsk and very low for the WHO European region.

Oct. 2: The lab worker dies in Shelekhov, and WHO begins monitoring media reports of a suspected plague death.

What Readers Want to Know

No. Russian authorities say the lab worker died of pneumonia of undetermined cause, and WHO says no cause of death has been officially confirmed.

Media outlets reported that a second institute employee had pneumonia of unclear origin. The Kremlin called the reporting false, and WHO has asked Russia to respond formally.

Early reports put the number at about 200. Rospotrebnadzor says more than 90% of contacts have completed monitoring and nearly 5,000 tests found no dangerous pathogens.

Is there a risk to the United States?

The CDC describes the risk as extremely low and says there is no indication of a broader threat. It is monitoring travelers from the region with other federal agencies.

The bacterium circulates naturally among small wild mammals and their fleas in parts of Siberia, as it does in parts of the western United States.

Yes. WHO says common antibiotics can cure plague when given early, although untreated pneumonic plague can be fatal within 18 to 24 hours.

WHO plans to update its risk assessment as Russia provides information, and the EU says it can reconvene its Health Security Committee on short notice.

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