A 28-year-old laboratory worker in Siberia has died after falling ill with a mysterious illness, prompting quarantine measures at several hospitals and the monitoring of nearly 200 contacts amid unconfirmed reports she may have been exposed to plague bacteria.
The worker, named in reports as Darya Shipilova, was employed at an anti-plague research institute in Shelekhov, near the city of Irkutsk. Unconfirmed reports have claimed she became infected after accidentally breaking a test tube containing plague bacteria while collecting samples. Russian health authorities have not confirmed that the woman had plague, with officials at health watchdog Rospotrebnadzor maintaining her diagnosis was "pneumonia of unknown aetiology".
What has happened?
Shipilova died on the night of October 2 at a regional hospital in Shelekhov, two days after falling ill, according to the Guardian. She had reportedly been diagnosed with pneumonia of "unknown origin". Russia's health watchdog, Rospotrebnadzor, said tests found no microorganisms linked to her professional work, whereas Alexey Tsydenov, head of neighbouring Buryatia, initially said the woman had died of plague before editing his statement to say she had "possibly" died from the disease, CNN reports.
Several hospitals in the Irkutsk region have reportedly been placed under quarantine, while contacts of the woman are being monitored. The Independent reported that at least 197 people suspected of having direct or indirect contact with the technician had been placed under medical isolation. One of the hospitals reportedly under quarantine is the one where Shipilova is understood to have passed away. On Friday (October 2), mayor Maxim Modin said it was no longer admitting or discharging patients, and its laboratory halted carrying out routine tests. The hospital's outpatient clinic kept operating as usual, he said.
Official response
Anna Popova, head of Russia's public health watchdog, Rospotrebnadzor, flew to Irkutsk and met governor Igor Kobzev and other officials on Friday. Kobzev said everyone who came into contact with the woman is under medical supervision. He did not identify the infection and called it a suspected case of "a particularly dangerous infection". Rospotrebnadzor was implementing "a full range of anti-epidemic measures", he added.
The Irkutsk Aluminium Plant in Shelekhov required staff to wear masks as a precaution, its director Artyom Fominykh said on Saturday (October 3), calling for calm and adding: "Better be safe than sorry."
What is pneumonic plague?
Plague is an infectious disease caused by bacteria called Yersinia pestis. It is most famously associated with the Black Death, which caused devastating outbreaks in Europe during the Middle Ages. But experts emphasise the plague has not fully disappeared. Dr Simon Clarke, Associate Professor in Cellular Microbiology & Public Engagement in Science at the University of Reading, said the bacteria continue to circulate naturally among wild animals, particularly rodents, and their fleas.
There are in fact "a few hundred cases of plague reported each year globally", according to Dr Malick Gibani, Clinical Associate Professor in Bacterial Vaccinology at Imperial College London. These are usually in geographically restricted areas including Madagascar and the Democratic Republic of Congo, he said, with smaller numbers of cases in the western United States, Central Asia and Mongolia. "Whilst the crude overall number of cases is low, there is a large zoonotic animal reservoir and there is therefore always a theoretical risk of zoonotic spillover," he added.
There are three main forms of plague: bubonic, septicaemic and pneumonic. Unlike the bubonic plague, which is typically associated with infected flea bites, the pneumonic plague can spread directly between people through respiratory droplets during close contact. Dr Clarke said pneumonic plague is "nearly always fatal if not treated promptly". Symptoms can include fever, headache, weakness and rapidly developing pneumonia, with shortness of breath, chest pain and coughing.
Should we be worried?
Reports of almost 200 people being monitored may sound alarming, but experts said identifying and monitoring contacts is a normal response from health authorities. Dr Gibani said: "Whether this is a high number is difficult to judge without more detail. In the event of a potential laboratory exposure, it would be normal to identify individuals who might have been exposed and to monitor them according to the assessed level of risk."
"If the reports are to be believed, there may be a lab worker who's been exposed to the Yersinia pestis bacteria. If that's the case, it would be reasonable to take precautions for anyone they've been in contact with," he added. Another expert, Prof Alice Hughes, Professor of Conservation Science at the University of Melbourne, said the reported lack of symptoms among contacts is reassuring. She said the incubation period for pneumonic plague is typically one to three days and that, because people were rapidly quarantined, it was "highly unlikely that it will spread further".
Dr Gibani added that it was important to wait and see how the situation develops. He said: "Based on the information we know, it seems as though this is a precautionary measure albeit one with high consequences."
How similar is this to Covid?
The reports have inevitably led people to draw comparisons with Covid-19 since pneumonic plague can spread through the respiratory route. However, experts say the two diseases are very different. Unlike Covid, plague is caused by bacteria rather than a virus and can be treated with antibiotics. Dr Clarke said: "Reports from Russia have inevitably drawn comparisons with Covid-19, but it is important to remember that pneumonic plague is a very different disease."
He added: "Unlike many viral respiratory diseases, plague is caused by bacteria and antibiotics such as fluoroquinolones and aminoglycosides work well against this pathogen if administered early enough and are often given prophylactically, post-exposure." This means there are established treatments and, following a potential exposure, antibiotics can also be used to reduce the risk of someone developing the disease.
Could this spread to the UK?
There is currently no evidence that the suspected case has or could spread to the UK. Experts have described the reported incident as a contained and rare event. Dr Zania Stamataki, Associate Professor of Viral Immunology, Academic Lead for Containment Level 3 Laboratories, University of Birmingham, said the UK has stringent controls around lab work involving Yersinia pestis. She said the bacteria are a Hazard Group 3 agent in the UK and that work with the viable organism takes place at Containment Level 3, meaning it requires strict laboratory conditions and security requirements.
For now, the reported quarantine appears a precautionary step to ensure that, if the worker did have pneumonic plague, any people who may have been exposed can be identified and treated. And while plague remains a serious disease, experts emphasise it is not another Covid-style threat. Dr Clarke added: "Any outbreak of plague is worrying, but this can be controlled and stopped with appropriate surveillance and control measures. Transparency, rapid diagnosis, and effective contact tracing will be the most important factors in managing this outbreak."
What does the Kremlin say?
Russian independent local news outlet Lyudi Baikala quoted sources it did not identify as saying Darya Shipilova died from pneumonic plague and that several Irkutsk hospitals were placed under quarantine. Asked on Monday (October 5) to comment on the case, Kremlin spokesman Dmitry Peskov said the public and media should follow official statements from Rospotrebnadzor, rather than "rumours or speculation".
The World Health Organisation describes pneumonic plague as a less common but severe form of plague – a disease caused by Yersinia pestis, a bacterium usually found in small mammals and their fleas. US secretary of state Marco Rubio said he does not think there is cause for alarm, but the White House is watching the case closely, aware that "it could spread quickly" despite the quarantine and other public health protocols.
