A biologic wastewater treatment plant was identified as a common source for 2 consecutive Legionnaires' disease clusters in the Netherlands in 2016 and 2017. Sequence typing and transmission modeling indicated direct and long-distance transmission of Legionella, indicating this source type should also be investigated in sporadic Legionnaires' disease cases.
Keywords: Legionella pneumophila; Legionnaires’ disease; Netherlands; bacteria; disease outbreaks; environmental exposure; waterborne diseases.