The death of a laboratory worker at a Russian research institute that studies plague has sparked fears of a possible infection, but experts say there is currently no evidence of a wider outbreak. The worker, identified by Russian media as 28-year-old Darya Shipilova, worked at the Irkutsk Anti-Plague Research Institute in Siberia. She died on 2 October after developing severe pneumonia of unknown cause.
Reports of a possible laboratory accident, including claims that a test tube containing plague bacteria was broken, have circulated online. Russian health authorities have rejected a link between her illness and pathogens handled at the institute.
According to ScienceAlert, neither plague nor the reported laboratory accident has been independently confirmed as the cause of the worker’s death.
Russian authorities have monitored people who came into contact with the woman as a precaution. About 200 people were initially placed under observation, but officials have reported no confirmed plague cases among her contacts.
Why are people worried about plague?
Plague is caused by the bacterium Yersinia pestis. Its pneumonic form affects the lungs and can spread through respiratory particles.
The disease can become severe very quickly if it is not treated. Brendan Wren, a professor at the London School of Hygiene & Tropical Medicine, told ScienceAlert that pneumonic plague can be rapidly fatal, while antibiotics can be effective when treatment is given early.
However, experts stress that the seriousness of pneumonic plague does not mean the Russian worker had the disease.
What would prove a laboratory infection?
A broken test tube alone would not establish that someone had been exposed to plague.
Zania Stamataki, an associate professor at the University of Birmingham, told ScienceAlert that a breakage in a high-containment laboratory would be treated as an incident, but not automatically as an exposure.
Such laboratories are designed with several layers of protection. Work with live pathogens is normally carried out inside biological safety cabinets, with filtered airflow and additional containment measures. Samples are also transported in sealed secondary containers.
Investigators would need to establish what was inside the container, where the incident happened and whether infectious material could have reached the worker.
One of the strongest pieces of evidence would be a genetic match between an organism found in the patient and a strain held at the laboratory.
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No evidence of a wider outbreak
The monitoring of around 200 contacts should not be interpreted as meaning that hundreds of people may have been infected, experts said.
ScienceAlert reported that such monitoring can be triggered by caution and suspicion while authorities establish what happened.
The absence of secondary cases would be consistent with a situation in which pneumonic plague was quickly contained. It could also mean that the original illness was not plague at all.
The case has drawn comparisons with earlier laboratory incidents, including a major anthrax outbreak in the Soviet city of Sverdlovsk in 1979. However, that outbreak involved a different pathogen, facility and historical situation, and provides no evidence that the current incident in Irkutsk is linked to a laboratory release.
For now, the key questions remain unanswered. Investigators will need to establish the worker’s actual cause of death and determine whether there is any connection between her illness and the laboratory.
