The death of a scientist in Irkutsk, Siberia, has revived attention to a disease that once reshaped Europe's history. The researcher died of pneumonia of unknown origin, prompting suspicions of pneumonic plague. Russian authorities have not confirmed any cases in the region, and tests on the woman's contacts came back negative. The World Health Organization has asked for more details and offered support.
Plague, caused by the bacterium Yersinia pestis, is no longer circulating routinely in Spain or the rest of Europe. According to the European Centre for Disease Prevention and Control (ECDC), the disease has been absent from the continent for over fifty years. But that does not mean the pathogen has vanished from the planet. It persists in wild rodent populations and their fleas across parts of Africa, Asia, and the Americas, causing sporadic human infections every year.
How real is the risk for Spain?
Spain has not recorded a locally acquired case of plague in decades, yet it maintains active epidemiological surveillance. In April 2026, the Public Health Commission updated the national protocol, refining case definitions and data collection procedures. This update, which predates the Siberian incident, is part of a broader early-warning system. The European Union discussed the Russian case on 7 October, but international health authorities are still awaiting clarifying information.
The ECDC has noted there is no evidence of secondary cases or sustained person-to-person transmission from the Siberian event. The WHO has assessed the risk to the European region as very low. Still, the persistence of the bacterium in animal reservoirs means the disease can appear wherever those reservoirs exist, even if human cases are rare.
Plague's global footprint
According to the WHO, plague remains endemic in several countries. Between 2019 and 2025, most reported human cases were concentrated in Madagascar and the Democratic Republic of the Congo. In Madagascar, bubonic plague cases occur nearly every year during the epidemic season from September to April. The disease also appears sporadically in parts of Asia and the Americas; in the United States, an average of about seven human cases are reported annually, mainly in rural western areas.
The difficulty of eradicating plague lies in its natural cycle. Yersinia pestis lives in wild rodents and their fleas, making it impossible to eliminate completely. Even when human cases are scarce, the bacterium can persist silently in animal populations.
Bubonic, pneumonic, septicaemic: the three faces of plague
Plague manifests in three main forms. Bubonic plague, the most common, follows a flea bite and causes fever, malaise, and painful swollen lymph nodes called buboes. Pneumonic plague affects the lungs and is particularly dangerous because it can spread from person to person via respiratory droplets. Without treatment, it can progress rapidly and be fatal. Septicaemic plague occurs when the bacterium enters the bloodstream, leading to a severe systemic infection.
Unlike during the Black Death, plague today is treatable with antibiotics. Early diagnosis is crucial to prevent complications and reduce mortality. The availability of effective treatment fundamentally changes the threat profile compared to the 14th century.
For Spain and Europe, the practical takeaway is vigilance rather than alarm. The EU's demand for transparency from Russia reflects a broader concern about global health security. While the immediate risk is minimal, the episode underscores the importance of maintaining robust surveillance and response systems. As historical analysis of the Black Death in Germany shows, the disease's past is a reminder of how quickly it can spread under the right conditions.
In Spain, the updated protocol is part of a wider European framework. The recent menopause drug shortage highlighted how supply chain vulnerabilities can affect public health, but plague preparedness relies on different mechanisms—surveillance, diagnostics, and antibiotics. The reported second case in Siberia has prompted calls for more openness, but so far, no spread has been detected.
Ultimately, plague remains a global concern, but Europe's health systems are far better equipped than in centuries past. The disease still exists, but the conditions that allowed the Black Death to devastate the continent are gone. For now, the risk to Spain and Europe is very low, and the focus remains on monitoring and preparedness.
