An outbreak of Legionnaires' disease linked to a municipal and industrial wastewater treatment plant, The Netherlands, September-October 2022
Pijnacker, Roan Brandsema, Petra Euser, Sjoerd Vahidnia, Ali Kuiter, Arnold Limaheluw, Jesse Schout, Christine Haj Mohammad, Gaaled Raven, Stijn
Pijnacker, Roan
Brandsema, Petra
Euser, Sjoerd
Vahidnia, Ali
Kuiter, Arnold
Limaheluw, Jesse
Schout, Christine
Haj Mohammad, Gaaled
Raven, Stijn
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Open Access
Type
Article
Language
en
Date of publication
2024-05-16
Year of publication
Research Projects
Organizational Units
Journal Issue
Title
An outbreak of Legionnaires' disease linked to a municipal and industrial wastewater treatment plant, The Netherlands, September-October 2022
Translated Title
Published in
Euro Surveill 2024;29(20):2300506
Abstract
Wastewater treatment plants (WWTPs) are increasingly identified as Legionnaires' disease (LD) sources. An outbreak investigation was initiated following five LD cases reported in September 2022 in Houten, the Netherlands. Case identification was based on the European LD case definition, with symptom onset from 1 September 2022, residence in or within 5 km of Houten, or visit to Houten within the incubation period, without other likely sources. We sampled potential sources and genotyped environmental and clinical isolates. We identified 15 LD cases with onset between 13 September and 23 October 2022. A spatial source identification and wind direction model suggested an industrial (iWWTP) and a municipal WWTP (mWWTP) as potential sources, with the first discharging water into the latter. Both tested positive for Legionella pneumophila serogroups 1 and 6 with multiple sequence types (ST). We detected L. pneumophila sg1 ST42 in the mWWTP, matching with one of three available clinical isolates. Following control measures at the WWTPs, no further cases were observed. This outbreak underlines that municipal and industrial WWTPs can play an important role in community LD cases and outbreaks, especially those with favourable conditions for Legionella growth and dissemination, or even non-favourable conditions for growth but with the influx of contaminated water.