The disease behind Europe’s most devastating historical outbreaks, plague, has resurfaced in global discussions after a scientist in Irkutsk, Siberia, died from pneumonia of an unidentified origin. Russian officials confirmed that no plague cases were found in the region, and tests on individuals in close contact returned negative results. The World Health Organization requested additional information but dismissed concerns about immediate transmission risks.
This development has renewed concerns about whether plague could reappear in Europe, despite the absence of locally transmitted cases for over five decades. The European Centre for Disease Prevention and Control (ECDC) has stated that plague is not currently spreading in Spain or anywhere else on the continent, though the disease has been absent from the continent for more than 50 years. This does not mean, however, that the bacterium has been eradicated from the planet.
The bacterium responsible, Yersinia pestis, continues to thrive in wild rodent populations and fleas across parts of Africa, Asia, and the Americas. While Europe has not recorded any locally acquired infections in recent years, the pathogen’s presence in animal reservoirs ensures its potential to re-emerge. Transmission to humans occurs through flea bites, direct contact with infected animals, or—most dangerously—respiratory droplets in the case of pneumonic plague.
Plague’s lingering hotspots in Africa and Asia
The ECDC has stated that plague is not currently circulating routinely in Spain or in the rest of Europe. However, the disease remains active in other regions, particularly Madagascar and the Democratic Republic of the Congo, where most reported cases between 2019 and 2025 were documented. Madagascar experiences seasonal outbreaks annually, typically from September through April, with bubonic plague being the predominant form. The Democratic Republic of the Congo also reports frequent cases, though surveillance there remains limited due to conflict and infrastructure challenges. These regions highlight how plague persists in areas with high rodent populations and poor public health infrastructure.
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In the United States, an average of seven human cases are reported each year, primarily in rural western states. Because the bacterium persists in wild animals, elimination remains unlikely, even though human infections occur sporadically. Spain’s Health Ministry has strengthened its surveillance systems, including updated case definitions and monitoring measures introduced in April 2026. These revisions, which predated the Siberian incident, now include clearer guidelines for collecting epidemiological data and distinguishing between imported and locally acquired cases. The updates reflect broader EU efforts to maintain readiness against potential reintroductions.
Three plague forms and why early treatment matters
Plague can appear in three forms: bubonic, which is the most common and spreads through flea bites; pneumonic, which is transmitted via respiratory droplets and is fatal if untreated; and septicaemic, a bloodstream infection. Bubonic plague typically presents with fever, swollen lymph nodes (buboes), and general malaise, while pneumonic plague progresses rapidly, causing severe respiratory distress. Septicaemic plague occurs when the bacterium enters the bloodstream, leading to systemic infection. Early diagnosis and treatment with modern antibiotics can effectively combat all forms, though delayed care significantly raises the risk of death. The Siberian case, though not confirmed as plague, has led European health agencies to increase vigilance, particularly for atypical pneumonia cases in high-risk populations.
On October 7, the European Commission convened a Health Security Committee meeting to address the incident, while the ECDC reiterated that there was no evidence of secondary transmission. The WHO has concluded that the risk to the European region is very low.
