The case began with the death of Daria Shipilova, a 28-year-old employee of the Irkutsk Anti-Plague Research Institute. She was admitted to hospital on 29 September with severe pneumonia and died a few days later. Independent Russian media outlets claimed that she had previously accidentally broken a tube containing the bacterium Yersinia pestis, which causes the plague. However, this version of events has not been officially confirmed. Russian health authorities, on the other hand, claim that tests have not revealed any bacteria linked to her professional activities and refer to “pneumonia of unknown origin”.
What is fuelling speculation is the scale of the precautionary measures. Nearly 200 people who may have come into contact with the young woman have been placed under medical observation, several dozen employees of the institute have been isolated, and restrictions have been imposed on certain hospital departments. So far, no human-to-human transmission of the plague has been confirmed and no outbreak has been identified.
The European Union and the US health authorities are nevertheless monitoring the situation closely. This is understandable: if the diagnosis of pneumonic plague were ultimately confirmed, it would be an infectious disease requiring an extremely rapid response. The European Commission has stated that it is monitoring the situation and stands ready to coordinate a response should developments require it.
This is because the plague has never truly disappeared from the planet. The bacterium Yersinia pestis still circulates naturally amongst certain wild rodents and their fleas. The World Health Organisation points out that human cases continue to emerge, mainly in certain regions of Africa, Asia and the Americas. Between 2019 and 2025, the majority of cases reported to the WHO came from the Democratic Republic of the Congo and Madagascar, amongst others.
There are several forms of the disease. Bubonic plague, the best known form, is generally transmitted to humans through the bite of a flea that has previously parasitised an infected animal. It causes, in particular, high fevers and extremely painful swelling of the lymph nodes, the so-called ‘buboes’. This form is very rarely transmitted directly between humans.
Pneumonic plague is a different matter altogether. When the bacterium reaches the lungs, an infected person can transmit Yersinia pestis to another person via respiratory droplets emitted, for example, when coughing. The disease can progress extremely rapidly: without treatment, it can become fatal in less than twenty-four hours. But we are no longer in the Middle Ages : the plague is a bacterial infection and antibiotics are effective when administered early enough. The WHO states that the chances of recovery are high when pneumonic plague is diagnosed and treated promptly.
The difference with Covid is also fundamental. The plague does not currently possess the epidemiological characteristics of a respiratory virus capable of circulating silently on a very large scale amongst the global population. Transmission of pneumonic plague generally requires close exposure to the respiratory secretions of an infected person. Its incubation period is short, usually between one and seven days, which also facilitates the identification and monitoring of contacts.
So, could we be affected in France? Theoretically, yes: as with virtually any infection present abroad, a case could be imported by a traveller. But in the current situation, the risk to the French population appears to be extremely low. First, the plague would have to be confirmed in Irkutsk; then it would have to be transmitted to other people; an infected person would have to travel to Europe during the short incubation period; and they would then have to have sufficiently close contact with others to transmit a possible pulmonary form of the disease.
France also has a specific surveillance system in place. Santé publique France points out that no case of plague has been diagnosed on French territory since 1945 and that one of the objectives of surveillance is precisely to rapidly identify any imported cases in order to treat the patient and their contacts. The Pasteur Institute is also home to the National Reference Centre for Plague and other yersinioses, which is able to intervene in the event of a suspected case.
There is therefore currently no reason to stockpile antibiotics, wear a face mask on the streets of France or fear the imminent return of a ‘Black Death’. Self-medicating with antibiotics would, moreover, be entirely unjustified. On the other hand, the events in Irkutsk warrant serious international monitoring, particularly as information from Russia has at times been contradictory and the exact cause of the young researcher’s death remains to be established.
The situation would, of course, change if several confirmed cases were to emerge amongst those in quarantine, and if infections were then detected beyond the initial circle of contacts. It is these two indicators – confirmed secondary cases and community transmission – that we will need to watch in the coming days, far more so than the rumours circulating on social media.
For the time being, therefore, we are a long way from a new Black Death and even further from a pandemic. But the Siberian incident serves as a reminder of an often-forgotten reality: the great diseases of history do not necessarily disappear. Some continue to circulate quietly in animal reservoirs. What has changed since the great medieval epidemics is our ability to identify the causative agent, isolate those who are ill, trace their contacts and, above all, treat them. The plague still exists. It is simply no longer the invincible enemy it once was.
