The death of a laboratory worker in Siberia has triggered a plague investigation. The worker died on October 2 at a hospital in Shelekhov near Irkutsk. She was a 28-year-old technician at the Irkutsk Anti-Plague Institute. Russian media identified her as Daria Shipilova. She was admitted to hospital on September 29 with a severe respiratory illness. Local reports said she broke a test tube holding live bacteria while working. Russia’s health watchdog Rospotrebnadzor said no plague was found. It said her death was from pneumonia of unknown origin. The agency said no plague cases were found among her contacts. About 200 people were placed under medical observation. The hospital where she died was quarantined. US Secretary of State Marco Rubio said Washington is closely monitoring the case. He said it was cause for focus, not alarm. Irkutsk governor Igor Kobzev said all contacts tested negative. Public anxiety is rising in Russia despite official reassurances. A criminal case has been opened into possible safety violations. The institute studies dangerous pathogens including plague.