Health authorities in Siberia’s Irkutsk region have placed nearly 200 people under medical observation after a laboratory worker died from plague.

Axar.az reports, citing The Moscow Times, that Alexei Tsydenov, head of the neighboring republic of Buryatia, confirmed that the woman had died from an unspecified form of plague. Irkutsk officials had previously described the illness only as a “particularly dangerous infection.”

Citing information from Russia’s consumer safety watchdog Rospotrebnadzor and Buryatia’s government, Tsydenov said the woman had not visited his republic and that her infection was unrelated to the region.

“There are no plague outbreaks in the republic, including in areas bordering Mongolia,” he wrote on social media.

The woman was identified as Daria Shipilova, a 27- or 28-year-old employee of the Irkutsk anti-plague institute, by the exiled news outlet Lyudi Baikala (People of Baikal) and pro-Kremlin broadcaster REN TV.

She reportedly told medical staff that she had accidentally broken a test tube containing live bacteria while collecting samples for testing.

She was hospitalized Tuesday with symptoms of severe pneumonia in Shelekhov, a town near the regional capital of Irkutsk. She was placed on a ventilator and died Thursday.