A lab worker's death has prompted health officials to take precautions. The 28-year-old researcher may have been exposed to pneumonic plague. Russian authorities have not confirmed the exact cause of death, but the country's consumer welfare service reported the researcher died of pneumonia with an unknown origin.

Almost 200 people who had contact with the researcher are under medical observation. This measure was taken as a precaution, according to Russian media reports. The incident occurred at an anti-plague institute. Further details about the situation are available from Russian media reports.