Key facts
- On 2 October 2026, according to multiple media reports with pending verification, authorities in Irkutsk Oblast, Russia, implemented emergency anti-epidemic measures following the death of a laboratory technician from the Irkutsk Research Anti-Plague Institute; the case was officially classified as pneumonia of unknown aetiology.
- Media reports alleged a laboratory incident involving Yersinia pestis.
- Public health measures included activation of an operational response plan, contact tracing, quarantine measures in healthcare facilities, and medical monitoring of approximately 189 contacts, all of whom reportedly tested negative at the time of reporting.
- On 4-5 October 2026, Rospotrebnadzor reported that expanded laboratory investigations had not identified microorganisms associated with the patient's professional activities, no infection clusters had been detected, and the epidemiological situation in Irkutsk and Shelekhov remained stable.
- ECDC is closely monitoring this signal and is in contact with WHO to verify the information.
- Based on the limited and unverified information currently available, there are no reports of secondary cases or sustained human-to-human transmission. Therefore, there is currently no indication of an increased public health risk beyond the reported event.
- The risk assessment will be reviewed when additional information becomes available.
Overview
On 2 October 2026, according to multiple media reports with pending verification, authorities in Irkutsk Oblast, Russia, initiated emergency anti-epidemic measures following the death of a 28-year-old laboratory technician, employed at the Irkutsk Research Anti-Plague Institute of Siberia and the Far East. Media reports, Russian authorities have officially classified the case as "pneumonia of unknown aetiology".
According to reports, the patient allegedly experienced a laboratory incident on 25 September 2026, when she reportedly broke a tube containing Yersinia pestis while working with live biological material. These reports have not been officially confirmed. Following the alleged incident, she reportedly became unwell within several days and was admitted to Shelekhov District Hospital on 29 September 2026 with severe pneumonia. Initial clinical suspicion reportedly included severe COVID-19; however, her condition deteriorated rapidly, requiring intensive care and mechanical ventilation. She died during the night of 1-2 October 2026 in the intensive care unit of Shelekhov District Hospital.
On 2 October 2026, the Governor announced that a suspected case of a "particularly dangerous infection" was under investigation and confirmed that a full package of anti-epidemic measures had been initiated. An extraordinary meeting of the regional sanitary and anti-epidemic commission was convened with participation of Head of Rospotrebnadzor and Chief State Sanitary Physician of the Russian Federation. An operational response plan was approved and contact tracing was initiated.
Public health measures included quarantine restrictions at Shelekhov District Hospital, suspension of admissions and discharges in affected departments, enhanced epidemiological investigations and medical monitoring of contacts. Russian media reported that approximately 189-200 contacts were placed under observation, including institute staff, healthcare workers, ambulance personnel and hospital patients. Identified 189 contacts have been isolated in medical institutions, of which 114 patients are in one hospital, 63 in another, and another 12 people are kept in the anti-plague institute. The Governor stated that all identified contacts were under medical supervision and had negative laboratory test results at the time of reporting.
Additional precautionary measures reported by Russian and independent media included cancellation of public events in Irkutsk, mandatory mask use at some workplaces, quarantine of several healthcare facilities, including the Shelekhov hospital, were the deceased person was hospitalised, and isolation of contacts in designated hospitals. These measures were implemented despite the absence of official confirmation of plague.
On 4-5 October 2026, Rospotrebnadzor, according to media reported that expanded laboratory investigations did not identify microorganisms associated with the deceased patient's professional activities. The agency stated that no laboratory accidents involving pathogenic microorganisms had been documented at the institute, no infectious disease clusters had been identified among staff, and the patient had been diagnosed with "pneumonia of unknown aetiology". Rospotrebnadzor further described the sanitary-epidemiological situation in Irkutsk and Shelekhov as stable.
No autochthonous plague cases have been reported in the EU/EEA in the last decades. The largest outbreak of pneumonic plague was reported in 2017 in Madagascar for which ECDC has previously published Rapid Risk Assessment: Outbreak of pneumonic plague in Madagascar: recent introduction in the Seychelles.
For more information about plague, please see ECDC factsheet.
Sources: media source 1, media source 2, media source 3, media source 4
ECDC assessment
At this stage, with only media reports quoting health authorities available, it is difficult to assess the circumstances surrounding the death of a laboratory technician reportedly diagnosed with “pneumonia of unknown origin”. According to media reports, it is possible that a laboratory worker was exposed to a sample containing Yersinia pestis and subsequently developed pneumonic plague, but this information has not been independently verified.
Pneumonic plague can be transmitted from person to person through infectious respiratory droplets generated by coughing. Transmission generally requires close and prolonged contact with a symptomatic patient. The disease can become severe but can be successfully treated with antibiotics, particularly when treatment is started early. Recommended antimicrobials include aminoglycosides such as streptomycin or gentamicin, as well as doxycycline and other effective antibiotics. Patients with suspected or confirmed pneumonic plague should be isolated, and close contacts should be rapidly identified, monitored and offered appropriate prophylaxis or treatment according to public health guidance.
Based on the limited information currently available, there are no reports of secondary cases or sustained human-to-human transmission. Therefore, there is currently no indication of an increased public health risk beyond the reported event. The risk assessment will be reviewed when additional information becomes available.