Basel authorities confirmed 26 cases of Legionnaires' disease, including 25 hospitalisations and one death. Two rooftop cooling towers on an office building tested positive for high levels of Legionella pneumophila and have been shut down for refurbishment. Residents with fever, cough or shortness of breath are urged to seek medical care while health teams continue inspections and monitoring.
Legionnaires' Outbreak in Basel: 26 Sick, One Dead — Rooftop Cooling Towers Linked
Basel is on the River Rhine and borders France and Germany (Fabrice COFFRINI)
Basel health authorities have confirmed an outbreak of Legionnaires' disease that has sickened 26 people and caused one death. Investigators have linked the cluster to high levels of Legionella pneumophila found in two rooftop cooling towers on an office building in central Basel.
Cases and Current Situation
Officials said 26 cases have been confirmed in total. Twenty-five people were hospitalised, seven of whom required intensive care at one point. As of the latest update, nine patients remain in hospital, including one in intensive care, and authorities reported one fatality.
Source and Investigation
Public-health teams tested water samples from 10 cooling facilities in the area. Two rooftop cooling towers on an office block showed high concentrations of Legionella pneumophila, the strain responsible for the majority of human infections. Both towers were taken out of service on Friday and are being refurbished while investigations continue.
About Legionnaires' Disease
Legionnaires' disease is caused by inhaling small droplets of water contaminated with Legionella bacteria, commonly found in freshwater, soil and man-made water systems. Symptoms can range from a mild, flu-like illness to a severe and potentially fatal pneumonia. Typical signs include fever, headache, profound tiredness, muscle aches, diarrhoea and sometimes coughing up blood. The illness is treatable with antibiotics.
Transmission and Risk Factors
The disease is not spread directly between people. Outbreaks are often associated with poorly maintained air-conditioning systems, cooling towers, hot tubs, humidifiers and complex water systems.
Public Advice and Local Context
Most cases were clustered in central Basel close to the River Rhine, with a few isolated infections elsewhere in the northern part of the city near the borders with France and Germany. Residents experiencing pneumonia-like symptoms — particularly fever, new or worsening cough, or shortness of breath — are advised to seek medical attention promptly.
Basel, with a population of about 180,000, is Switzerland's third-largest city and a major cultural centre; its economy is strongly supported by the chemical and pharmaceutical industries. Local health authorities continue to monitor the situation and carry out inspections of water systems across the city.
Note: Investigations and remediation work are ongoing. Authorities will release further updates as more information becomes available.
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