Cases of pneumonia from Legionella bacteria on the rise

Cases of pneumonia caused by Legionella bacteria have surged in the Netherlands, with factors like weather conditions and aging population as potential contributors, according to the National Institute for Public Health and the Environment (RIVM). In 2013, 180 people contracted Legionella-related pneumonia; by 2021, that number rose to 555 cases. In 2022, 484 cases were recorded.

Legionella bacteria, commonly found in water and soil, thrive in humid, cloudy weather. “Spikes in cases often follow heavy rain after warm, dry periods,” RIVM reported. Legionella exposure can occur through inhaling mist from contaminated sources like showers or hot tubs.

The Dutch Food and Consumer Product Safety Authority (NVWA) issued a safety alert in July 2023 regarding Legionella contamination in two Ferroli water heater models.

Symptoms generally appear within two to ten days after exposure and include headache, muscle pain, nausea, diarrhea, fever, and dry cough. In serious cases, Legionella pneumonia can cause high fever, difficulty breathing, chills, and confusion, particularly among older adults, smokers, and those with weakened immune systems.

Though Legionella pneumonia—also known as Legionnaires’ disease—primarily affects high-risk individuals, a 1999 outbreak in the Netherlands infected over 200 people, leading to 32 deaths.