Experts have raised concerns that a fatal laboratory leak in Russia could be part of a Vladimir Putin plot to weaponise the bacteria behind the Black Death, potentially spread by squirrels. The death of researcher Daria Shipilova has prompted questions about whether Moscow is hiding the truth about the incident.
Researcher's death and quarantine
The 28-year-old reportedly fell ill after accidentally dropping and smashing a test tube containing plague bacteria in a research lab. She was said to be working with Yersinia pestis, the bacterium responsible for plague and the medieval Black Death. Daria developed symptoms during an expedition in Buryatia, Siberia, where she was studying plague-infested squirrels. Wild rodents, particularly ground squirrels, chipmunks, and marmots, are known natural carriers of Yersinia pestis in the region, with fleas transmitting the bacteria.
Modern cases from natural exposure are rare and treatable with antibiotics. However, Daria was placed on a ventilator on September 29 and died three days later from what Russian health officials described as 'pneumonia' of unknown origin. Her death led to the immediate quarantining of 189 people who had come into contact with her at her lab in nearby Shelekhov. Hospitals have been placed under quarantine restrictions, events cancelled, and workers at a nearby aluminium plant ordered to wear masks.
Cover-up fears and international concern
The World Health Organisation has demanded details of the incident from Russia, which has denied there was a laboratory accident. Officials have insisted tests found no microorganism linked to Daria's work and maintain there was no plague outbreak. However, Russia's chief state sanitary doctor Anna Popova flew 2,600 miles from Moscow to Irkutsk to oversee the response. The extensive containment operation and lockdown of hospitals have sparked fears of a cover-up and raised questions about what was happening inside the lab.
Chemical and biological weapons expert Hamish de Bretton-Gordon said: "It is not beyond the bounds of possibility that they have an active biological weapons program. Because regulation is so poor, particularly in Russia, some of the scientists and some of these laboratories can possibly be used for really malign and malicious and dangerous activities. We now know there is a potential for some sort of plague-type pathogen to be travelling around."
Hamish said he did not understand why a vaccine did not save Daria, as it is routine practice for lab personnel to be vaccinated against the diseases they work with. He suggested this could indicate the scientist was working with a new strain of the plague that does not have a vaccine.
Potential bioweapon threat
Hamish said plague could be far deadlier than the pandemic. "Covid was a very transmissible but a very low potency pathogen. Covid killed less than 1% of people infected," he said. "Plague is something quite different. It has a mortality rate between 50% and 100% untreated." He described it as a 'classic Russian or Soviet-type doctrine' to impose a post-disaster information shutdown.
Professor Simon Clarke, head of biomedical sciences at the University of Reading, warned plague bacterium 'does have potential to be used as a bioweapon'. "It is no secret that could be something they were working on," he said. "There is speculation from a bioweapons perspective that antibiotic-resistant versions of the bacteria, Yersinia pestis, may have been developed in order to make them more difficult to treat. Under Putin Russia has revived and increased investment in its illegal biological weapons program at least at three military biological laboratories."
Dr Andrew Weber, who has visited anti-plague labs across the former Soviet Union, said UK health chiefs should consider bringing in passenger screening. The former US Department of Defence worker said: "If I were a public health authority in London I would be monitoring flights and passengers coming from the region and screening them at the airport."
International response and reassurance
US President Donald Trump has offered to help Russia tackle the crisis. "We're looking at it very strongly," he said. "We just heard about it and they call it pneumonia. And pneumonia, you know, years ago you could treat pneumonia easier. The microbes and the germs have gotten stronger disproportionately. But we'll help them." Trump warned the microbes had become 'stronger and smarter', adding: "They're like an army." US Secretary of State Marco Rubio said American health experts were 'watching and monitoring it closely' warning an outbreak 'could quickly spread'.
The World Health Organisation said it deemed the public health risk in Russia to be low but the country had not yet responded to its request for further information. WHO spokesman Christian Lindmeier said: "The illness initially presented as a typical acute respiratory viral infection. According to the test results no pathogens of dangerous infectious diseases were detected among any of the contacts. WHO is following the situation closely, working with headquarters to keep other countries informed."
British medics tried to calm fears saying plague can be treated by antibiotics and should not spread naturally. Brendan Wren, professor of Microbial Pathogenesis at the London School of Hygiene & Tropical Medicine, said: "Historically the disease was transmitted from infected fleas to humans, although human-to-human spread can occur through respiratory droplets in cases of pneumonic plague. It can cause a rapidly progressing septicaemia that may become life-threatening within 48 hours if left untreated. Reports from Russia about this case suggest that the infection resulted from an accidental inoculation following a broken test tube, highlighting the importance of strict biosafety procedures when handling dangerous pathogens.
"While this incident has attracted global attention, laboratory-acquired infections with Yersinia pestis are rare because human-to-human transmission of plague is relatively uncommon compared with respiratory viruses such as SARS-CoV-2 or COVID-19. In this case I would not describe the accidental laboratory-based transmission to a single individual as an outbreak and it seems unlikely that it will lead to a wider epidemic.
"Although pneumonic plague is the most severe form of the disease, as it can spread via the respiratory route, it remains treatable with antibiotics when diagnosed promptly. Globally, around 2,000 cases are reported each year mostly in areas where the disease remains endemic, including regions of the western United States, public health authorities within these regions have extensive experience in managing suspected exposures. In order to prevent further transmission in cases such as this, the monitoring and isolation of laboratory staff and other key contacts is a sensible and precautionary measure as it helps ensure any potential onward transmission is detected and treated quickly."
