Legionella is not to be taken lightly, as the message has spread by now. These bacteria in tap water can cause legionellosis (“Legionnaires’ disease”), a severe form of pneumonia that is often fatal. And although there are more and more warnings about it, the numbers in the EU have recently risen significantly. In 2021, they stood at over 10,700 reported cases and 704 known deaths, according to the ECDC’s latest report. At 2.4 cases per 100,000 inhabitants, this is the highest annual reporting rate for Legionnaires’ disease to date.

Although legionella are a natural component of drinking water, they multiply exponentially when suitable conditions such as water stagnation or temperatures between 20 and 45°C prevail in the pipes and fittings. They can then enter people’s lungs via water droplets, spray or steam, e.g. when showering or in a whirlpool. This can lead to the notorious Legionnaires’ disease. Healthy people are less likely to contract the disease, but children, the elderly and immunocompromised people have an increased risk. Men aged 65 and over, for example, are most affected, with a rate of 8.9 cases/100,000 inhabitants.

It is also worrying that 75% of all reported cases are in the four (holiday) countries Italy, France, Spain and Germany. The cause of this development is not yet known. It could be related to the ageing of society, the ageing of drinking water infrastructure, climate changes, but also changes in testing procedures and reporting rates.

The number of travel-associated infections has also increased

In 2021, there were 895 cases of travel-associated infections with Legionnaires’ disease, up 38% from the previous year. But how can holidaymakers protect themselves when travelling? One method that does not guarantee complete protection, but can at least reduce the high germ load in the water pipe, is to run hot and cold water for five minutes before taking your first shower, without creating too much steam. When doing this, place the shower hose on the floor of the bathtub and let any standing water in the pipes run off.

Legionella can also occur wherever people may be exposed to aerosols containing bacteria, e.g. in steam baths, whirlpools, through humidifiers, decorative fountains or fans with spray.

Responsibility of the operator

Ultimately, it is the host’s responsibility to ensure hygienically safe drinking water installations. Hotel operators and landlords of holiday flats can effectively protect their guests from legionella by eliminating stagnant water and dead pipes, ensuring hot water temperatures of 55 to 60 degrees and installing Seccua ultrafiltration systems at the point where drinking water enters the building from the public mains. The medical-grade membrane acts virtually like a firewall, keeping out legionella, other pathogens and sediment.

Ongoing maintenance, cleaning and disinfection of the water and sanitary facilities as well as regular checks of the pipe network for legionella and appropriate countermeasures in consultation with the local health authority minimise the risk of unnoticed legionella contamination. In the event of an emergency, the operator of the drinking water system is liable.