Cluster of Legionella Cases in the Greater Linz Area: Authorities Search for Source in Linz AG Cooling Towers

Cooling Towers of Linz AG in Focus

At the center of the search for the source of infection are currently cooling towers operated by Linz AG. The company operates several facilities within the city area whose water-bearing components must be regularly tested for microbial contamination. According to the investigations, more than 80 environmental examinations have already been completed, while additional ones are still being analyzed.

The city of Linz, together with the state of Upper Austria, is providing information on possible symptoms and is calling on people to seek medical help promptly if signs of illness appear. Those affected are asked to provide samples from water fittings and showerheads so that laboratories can specifically search for Legionella.

Experts emphasize that Legionella do not multiply in flowing water but require biofilms on surfaces. Regina Sommer, head of the Department of Water Hygiene at the Medical University of Vienna and co-director of the Interuniversity Competence Center Water & Health, explained: „Die müssen sich irgendwo hinsetzen können." This puts particular focus on water pipes, showers, and evaporation systems, where stagnant or slow-moving water at moderate temperatures finds ideal conditions.

How Legionella Cause Illness

The medical background is clear: if Legionella-containing aerosols – that is, fine water droplets – are inhaled, severe pneumonia can result. Particularly at risk are elderly people, smokers, and individuals with weakened immune systems. The authorities point out that most illnesses occur with a time lag of a few days from the actual infection.

In parallel with the laboratory analyses, the search for clues is underway throughout the city area. According to its own statements, Linz AG has intensified its internal controls in recent days and temporarily taken individual facilities offline until negative results are available. The state of Upper Austria is accompanying the measures and providing information for property management companies.

Measures by the City and Linz AG

For the public, the city of Linz has published behavioral guidelines. These include briefly flushing long-unused water pipes before use and having the temperature of hot water tanks checked regularly. Showerheads and aerators should also be cleaned or replaced at certain intervals in order to remove biofilms.

The investigators view the current case as a complex event in which multiple facilities and pipe systems may interact. As long as the epidemiological assignment – that is, the question of which source is concretely responsible for the illnesses – is not completed, individual cooling towers remain out of operation. Only afterwards, according to AGES, can the risk be reliably assessed and further steps decided.

External Expertise Deployed

The authorities are also receiving support from external experts. Hans-Peter Hutter, an environmental medicine specialist at the Medical University of Vienna, is among the experts whom the state of Upper Austria is consulting in an advisory capacity as part of the investigations. He and other specialists are to help medically and epidemiologically classify the findings from the environmental samples.

City politicians are also following the developments closely. Health councillor Hildegard Kollnberger is continuously informing herself about the status of the investigations, according to information from City Hall. The goal, both the city and the state emphasize, is to identify the source of infection as quickly as possible, to remediate affected facilities, and to restore the population's confidence in the drinking water supply.