Darya Shipilova, a 28-year-old researcher at the Anti-Plague Institute of Siberia and the Far East in Irkutsk, died on October 2, 2026, prompting Russian authorities to place nearly 200 people under medical observation amid unconfirmed concerns over pneumonic plague. Key Details of the Incident The Victim: Darya Shipilova, 28, worked at the Irkutsk Anti-Plague Research Institute in southeastern Siberia. Official Cause of Death: Russia's consumer welfare and health watchdog, Rospotrebnadzor, stated she died of "pneumonia of unknown etiology" (undetermined origin). An autopsy revealed two cases of COVID-19 and two cases of rhinovirus, with no plague pathogens detected. The Response: Close to 200 contacts were placed under precautionary medical observation, and a local inpatient facility in the Shelekhov district near Irkutsk was temporarily quarantined. Rospotrebnadzor later reported that over 90% of those contacts finished observation with no health disorders. Rumors vs. Official Stance: Unconfirmed media reports and online speculation suggested she fell ill after breaking a test tube containing Yersinia pestis (plague) or after a field trip. Russian officials and Rospotrebnadzor denied any epidemic risks. International Reaction: The World Health Organization (WHO) and U.S. officials requested further transparency and information from Russia regarding the death and unverified reports of a second pneumonia case tied to the institute.