Irkutsk: The ghosts of the Covid-19 pandemic returned to haunt the global medical fraternity after the death of a 28-year-old laboratory worker at a Russian anti-plague institute in Siberia.
According to reports, she died after developing severe pneumonia. US officials now monitoring reports that she may have contracted pneumonic plague in what could be a laboratory-related incident.
Identified as Darya Shipilova by local media, the researcher worked at the Irkutsk Anti-Plague Research Institute in Shelekhov, in Russia’s remote Irkutsk region. Reports about her death raised concerns over a possible exposure to the bacterium that causes plague, although Russian health authorities have not officially confirmed pneumonic plague as the cause behind her death, as reported by News18.
Rospotrebnadzor, Russia’s consumer and public health watchdog, said the employee was diagnosed with pneumonia of unknown aetiology. Expanded testing of samples from the patient had found no microorganisms associated with her professional activities, the agency said.
However, nearly 200 people who may have had contact with the woman have reportedly been placed under medical observation as authorities carry out preventive measures.
Laboratory accidents involving dangerous pathogens are rare but they have happened. One of the clearest examples came in 2003, after the SARS outbreak had officially ended. A 27-year-old researcher working in a virology laboratory in Singapore contracted SARS-CoV.
The researcher most likely acquired the infection through accidental contamination in the laboratory the World Health Organization (WHO) later concluded. The investigation identified inappropriate laboratory practices that had contributed to the accident.
Fortunately, the Singapore case did not lead to further transmission but WHO warned that an accidental laboratory exposure could potentially restart SARS transmission, given the number of laboratories around the world handling the virus or retaining samples from SARS patients.
There were also other laboratory-associated SARS infections around the same period, including cases reported in Taiwan and China. WHO subsequently strengthened its guidance on handling and storing SARS coronavirus material.
Russia has had its share of incidents. An outbreak of inhalational anthrax killed dozens of people after anthrax spores were accidentally released from a military microbiology facility in Sverdlovsk, now Yekaterinburg, in the former Soviet Union in 1979.
Smallpox also made a comeback due to a laboratory accident. The last naturally occurring case of smallpox was recorded in Somalia in 1977. But a year later, a laboratory accident in Birmingham, England, caused the disease to reappear.
According to the WHO, the 1978 laboratory accident caused a limited outbreak and killed one person. It remains the only known human smallpox cases after the disease’s natural eradication to have been caused by a laboratory accident.
The more recent Covid-19 outbreak that took millions of lives globally is still very much in people’s memories. Although, there is no established evidence that SARS-CoV-2 caused the COVID-19 pandemic because of a laboratory accident, one possibility was a leak from a facility in Wuhan, China.
In its latest major assessment, published in 2025, the WHO’s Scientific Advisory Group for the Origins of Novel Pathogens said the available evidence favoured zoonotic spillover, meaning transmission from animals to humans. However, WHO also said that important information needed to fully evaluate all hypotheses had not been provided and that the laboratory-related hypothesis could not be completely ruled out.
It remains unknown whether the pathogen has spread beyond Shipilova. The key question is not simply whether she had plague, but whether she was infected with a pathogen capable of spreading to other people and, if so, whether anyone else was exposed.
Pneumonic plague is caused by Yersinia pestis and affects the lungs. Unlike the more familiar bubonic form, pneumonic plague can spread between people through respiratory droplets. It can be extremely serious, but early antibiotic treatment can be effective.