The World Health Organization (WHO) said on October 8 that it has still not determined what caused the pneumonia that killed a female laboratory worker at a Russian plague research institute, and confirmed that no plague cases have been recorded.
According to the United Nations health agency, Russian health authorities have reported that tests on the woman and her contacts came back negative for the dangerous pathogens that were checked. The contacts have shown no symptoms, and no further severe pneumonia cases linked to the incident have been detected.
The WHO stated: "Based on the information provided… WHO has found no evidence of ongoing transmission related to this event. The key remaining uncertainty is the absence of a confirmed diagnosis in the laboratory worker who died."
How the incident unfolded
The woman fell ill and died under circumstances that have not been made public on October 2, prompting authorities to quarantine about 200 people and fueling concern on social media.
Russian media identified the victim as Darya Shipilova, 28, a laboratory technician at the Irkutsk Research Anti-Plague Institute of Siberia and the Far East, in the Irkutsk region of Siberia.
Authorities initially suspected pneumonic plague — a lung infection caused by the bacterium Yersinia pestis, which typically lives in small mammals and their fleas.
The governor of neighboring Buryatia region had said the woman "may have died of plague." Russia's health watchdog Rospotrebnadzor said she was diagnosed with "pneumonia of unknown origin."
Russian officials said the worker had been fully vaccinated and that no microorganisms related to her work were found in her body. Post-mortem tests also found no plague.
On October 6, Russia said it had completed health checks on all of the victim's contacts and provided full information to the WHO. A local official said the same day that 60% of those quarantined had been released.
Earlier, on October 5, WHO Director-General Tedros Adhanom Ghebreyesus asked Russia to respond to media reports about a second worker with pneumonia of unknown origin. Russia dismissed those reports as "misinformation."
The United States also called on Russia to be transparent about the incident.
Global health authorities have been especially vigilant about fatal pneumonia cases of unknown cause since the COVID-19 pandemic, which began with a fast-spreading and deadly cluster of respiratory cases in China. The cause of isolated pneumonia cases often cannot be determined.
