WHO unsure what caused pneumonia that killed plague-lab worker in Russia

AI Summary

The WHO said it is uncertain what caused pneumonia that killed a worker at a plague laboratory in Russia. Authorities quarantined about 200 people after the worker became ill and died on October 2, prompting public concern.

The lab worker fell ill and died in undisclosed circumstances on Oct 2, prompting authorities to quarantine about 200 people and causing public health fears on social media.