Legionella outbreak at Basel's Manor branch ended after authorities give all-clear

According to current findings, those affected by the outbreak were predominantly people who had used the shower facilities in the employee or customer area of the building on Rebgasse. After the elevated readings became known, the health department had worked closely with Manor management and specialist laboratories to precisely narrow down and specifically eliminate the source of the bacterial contamination. When exactly the first case became public had not previously been specified in detail by the department.

What makes Legionella dangerous

The pathogens, Legionella, multiply particularly in warm, stagnant water between about 25 and 45 degrees Celsius. They can enter the lungs when fine droplets are inhaled, for example while showering, and trigger severe pneumonia. In buildings with complex pipe systems that are only sporadically flushed through, the risk is empirically elevated, which is why, following the incident in Basel, other properties are also coming into focus.

According to the department's assessment, there is currently no increased risk of infection for the population in Basel-Stadt. Those responsible emphasize, however, that compliance with simple hygiene rules remains advisable. This includes regularly flushing rarely used pipes and keeping the hot water temperature constantly above 55 degrees Celsius, as higher temperatures make it more difficult for the bacteria to multiply.

In parallel with the ongoing inspections, the health department had launched a broad-based information campaign for the public. In addition to media releases, notices were also sent to property management companies and larger employers in the canton. This is intended to ensure that the necessary precautions are also taken in residential buildings, hotels, and sports facilities, according to the department.

Recommendations for private households

Manor management, according to the department, was cooperative and promptly implemented all necessary steps. The affected showers and water outlets have in the meantime been thoroughly flushed and disinfected. Internal inspection intervals have also been increased in order to detect any renewed rise in bacterial levels at an early stage.

With the all-clear now issued, operations on Rebgasse are returning to normal. Customers and employees can use the sanitary facilities without any special precautions. However, the health department intends to continue documenting the case and incorporate the findings into the cantonal recommendations on drinking water hygiene.

The canton therefore recommends that private households correctly set hot and cold water temperatures, avoid prolonged water stagnation, and thoroughly flush pipes after longer absences. This is intended to prevent the pathogens from multiplying again in stagnant hot water.

Looking ahead: stricter monitoring

Overall, the authorities assess the course of the outbreak as mild. Thanks to a rapid response and coordinated cooperation between the canton, Manor, and specialist laboratories, the situation was brought under control without a broader wave of illness occurring.

For the future, the health department announces that it will further intensify the monitoring of drinking water installations in large buildings. Training for caretakers and technical minimum standards are intended to help detect similar incidents at an early stage in the future or avoid them altogether.