The Centers for Disease Control and Prevention said Tuesday it is aware of and closely monitoring reports of a suspected case of pneumonic plague in Russia’s Irkutsk region that resulted in a death, while stressing that the circumstances remain unconfirmed and that there is no indication of a broader threat to the United States.
Atlanta-Based CDC Responds to Plague in Russia
In a statement, the Atlanta-based agency said it is working across the U.S. government to assess developments as additional information becomes available. “While the circumstances of this reported case remain unconfirmed, plague is a serious bacterial disease that is treatable with antibiotics, particularly when recognized and treated early,” the CDC said. It noted that pneumonic plague can spread person-to-person through respiratory droplets during close contact, making rapid identification, treatment of infected individuals, and monitoring of potentially exposed people important public health measures. “At this time, there is no indication of a broader threat to the United States, but CDC and our interagency partners are prepared and will continue to monitor the situation closely.”
The statement follows the death last week of a 28-year-old laboratory worker at the Irkutsk Anti-Plague Research Institute of Siberia and the Far East, identified in Russian media as Darya Shipilova.
She was hospitalized in late September in the town of Shelekhov, near Irkutsk in southeastern Siberia, and died around October 1–2 after developing severe pneumonia. The institute studies dangerous pathogens, including the bacterium that causes plague, in a region where the disease occurs naturally in wild rodents.
Russian health authorities have not confirmed plague as the cause of death. Rospotrebnadzor, the country’s consumer and health watchdog, has described the illness as pneumonia of unknown etiology and said extensive testing found no microorganisms linked to the worker’s professional duties in her samples.
Officials have also denied reports of a laboratory accident involving pathogenic material and said no infectious diseases of concern had been reported among institute staff in the days surrounding the death. Contacts—reported in some accounts to number around 200—were placed under medical observation or quarantine as a precaution; local officials later said a substantial share had been released after testing and monitoring showed no signs of related illness.
The World Health Organization said Tuesday that Russian authorities told it no case of plague had been recorded in the city of Irkutsk, that contacts had been identified, and that tests for dangerous pathogens among them were negative. A WHO spokesperson assessed the risk as moderate to low for Irkutsk, low for Russia overall, and very low for the WHO European region, adding that none of the monitored contacts had shown symptoms of illness.
Secretary of State Marco Rubio, speaking in Iceland, urged Russia to share more information so that other countries could respond appropriately, while noting that speculation would be premature given limited details. President Donald Trump has also publicly offered U.S. assistance.
Unconfirmed accounts circulating in Russian media and on social media have suggested possible explanations ranging from a broken test tube containing live bacteria to recent travel, but authorities and independent reporting have not substantiated those claims.
Plague, caused by Yersinia pestis, remains endemic in parts of Asia, Africa, and the Americas, including the western United States, where a small number of human cases occur each year, mostly bubonic and linked to rodent fleas. The pneumonic form is less common but more readily transmissible between people in close contact; early antibiotic treatment sharply reduces the risk of death.
U.S. officials have said they continue to track the situation through the CDC and other agencies. As of Tuesday, neither Russian authorities nor the WHO had reported additional confirmed cases or evidence of sustained person-to-person transmission.
