ECDC: Legionella outbreak may be reduced with appropriate controls

The Legionella bacterium develops primarily in warm, stagnant water. [SHUTTERSTOCK]

A new outbreak of the Legionella bacterium in Belgium’s Flanders region has brought the so-called ‘Legionnaires’ disease’ into the limelight. According to the EU agency for infectious diseases control, contraction of the condition is spreading rapidly in Europe.

Belgium’s regional health authorities say 32 people have been infected with Legionella in Evergem, a municipality belonging to the port of Ghent area. Two patients have already died died due to the effects of Legionnaires’ disease.

Initial symptoms of illness occurred in some patients between 29 April to 6 May, while a second group reported symptoms of Legionnaires’ disease between 7 and 10 May.

The public prosecutor’s office in East Flanders has launched its own investigation, while Belgian authorities are now in charge of managing the outbreak, including the implementation of control measures.

According to the Flemish Agency for Care and Health in Belgium, the local paper mill of the pulp company Stora Enso might be behind the recent Legionella outbreak in Flanders.

“The plant took measures, such as sampling and disinfection, in close cooperation with the authorities and with international and national legionella experts,” said the mill manager Chris De Hollander in a press release.

He also added that the company decided to stop the cooling tower for a thorough one-off offline cleaning and disinfection, with the approval of the Flemish Health Agency.

Following the Legionella contamination, the municipality of Evergem lodged a complaint as a plaintiff. The municipality will also bear the costs for residents asking for legal advises and victims of the epidemic will jointly file a complaint against the company reportedly responsible.

ECDC warning

As part of its routine daily work, the European Centre for Disease Prevention and Control (ECDC) has been monitoring outbreaks of Legionnaires’ disease through activities of epidemic intelligence and surveillance and through the disease network of ELDSNet, which reports on any travel-associated cases.

The latest information on community outbreak is available on the EU agency’s weekly summary that gathers all epidemic intelligence activities regarding communicable diseases of concern to the EU.

“‘Legionnaires’ disease is increasing in the European Union and the European Economic Area,”  Johanna Takkinen, head of disease programme food- and waterborne diseases and zoonoses at the EU agency, told

“Most reported cases are sporadic but community outbreaks are also reported every year to the ECDC,” she added.

The increasing trend in overall numbers of cases since 2013 and in particular since 2017 is probably driven by several factors, including improved surveillance, an ageing population, travel patterns and changes in climate and weather factors, according to the ECDC.

The EU medical advisers also informed that regular checks for the presence of Legionella bacteria and appropriate control measures applied to engineered water systems may prevent cases of Legionnaires’ disease at tourist accommodation sites and in hospitals, long-term healthcare facilities or other settings where sizeable populations at higher risk may be exposed.

The deadly form

The Legionella bacterium develops primarily in warm, stagnant water. Legionnaires’ disease occurs by inhaling aerosols carrying the Legionella bacteria, with infection leading to pneumonia.

There are more than 60 Legionella species officially described. However, according to the most important health bodies such as the World Health Organisation (WHO) and the ECDC itself, 96% or more cases of Legionnaires’ diseases are caused by just one specific species, Legionella pneumophila, which is the one that causes the deadly form of pneumonia.

“Clinicians should be aware of the disease, particularly if atypical pneumonia is diagnosed in persons who are at increased risk,” said ECDC’s Takkinen, adding that people over 50 years of age and those having underlying diseases are more at risk.

The issue of monitoring Legionnaires’ disease is also touched upon in Annex III of the new Drinking Water Directive (DWD), a crucial health dossier for the next Finnish presidency.

Negotiations between EU ministers and the European Parliament to approve a common text for the directive that will update the parameters of water quality standards set more than 20 years ago are supposed to start before the end of this year.

However, the current Council position raised some criticism when it comes to regulating the microbiological parameter for Legionella pneumophila, as it does not seem consistent with the so-called risk-based approach for monitoring water quality.

This approach consists of decreasing the costs of monitoring while guaranteeing the highest quality of drinking water, focusing on parameters that most likely cause harm to human health, in an attempt to rationalise the monitoring and save time in case of severe threats to health.

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[Edited by Zoran Radosavljevic and Samuel Stolton]


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