A Russian report says a worker at a Siberian plague institute fell ill and died of an unknown cause

A staffer at the Irkutsk Anti-Plague Research Institute contracted pneumonia of an unknown cause

Russian state TV reported she died last week in a hospital in Shelekhov, near Irkutsk

The hospital was placed under quarantine and stopped admitting or discharging patients

Rospotrebnadzor said extensive testing found no microorganisms linked to her professional work with pathogens

last week: The woman died in a hospital in Shelekhov · Friday: The hospital was placed under quarantine and Anna Popova met with Gov. Igor Kobzev in Irkutsk · Saturday: The Irkutsk Aluminum Plant required staff to wear masks as a precaution · Sunday: Rospotrebnadzor announced she had 'pneumonia of unknown etiology' and found no related pathogens · Monday: A state TV station in Irkutsk reported her death, and Kremlin spokesman Peskov commented on the case

The exact cause of her pneumonia, described as 'unknown etiology'