Moscow, Oct. 5 -- Russian health authorities have denied reports that a laboratory worker at an anti-plague institute in Siberia died of plague, saying tests found no pathogen linked to her professional activity. The denial comes as more than 60 colleagues remain isolated and quarantine restrictions continue at several hospitals in the Irkutsk region, Euronews reported.

According to Euronews, citing Russia's national health watchdog, Rospotrebnadzor, on Monday, tests of biological material from Daria Shipilova, a 28-year-old laboratory assistant at the Irkutsk anti-plague institute, found no microorganisms associated with her work.

It also said no accidents involving pathogenic microorganisms had been detected at the institute.

Shipilo...