Multiple reports indicate Legionnaires' disease cases are increasing across parts of the United States. In North Carolina, officials issued an alert after recording 310 Legionnaires' disease cases in 2025, a 54% increase from the previous year. The state has registered 48 Legionnaires' disease infections so far in 2026. Health officials in North Carolina have not released further details on the cases, including whether any patients were hospitalized or died, how they were infected, or a potential source. In 2025, an outbreak of Legionnaires' disease was recorded in Gaston County, outside Charlotte, that sickened 17 patients.
Ector County in south Texas issued an alert after detecting 12 Legionnaires' disease cases and two deaths between late December and early January. Politicians in Baltimore, Maryland, have alleged that Legionella bacteria caused an outbreak this month at a federal building housing ICE detainees.
Legionnaires' disease is a serious type of pneumonia caused by the bacterium Legionella pneumophila. People contract the disease by breathing in fine water droplets containing Legionella.
Nationwide Legionnaires' disease infections in the US have increased nearly 1,000% over two decades, from 1,100 cases in 2000 to more than 8,000 today. Health experts say warmer temperatures are allowing Legionella bacteria to thrive in damp locations, raising infection risk.
Legionnaires' disease is a serious type of pneumonia caused by the bacterium Legionella pneumophila. People contract Legionnaires' disease by breathing in fine water droplets containing Legionella bacteria. Legionella bacteria thrive in warm, stagnant water such as hot tubs, plumbing systems, and large air-conditioning units.
This bacteria thrives in warm, stagnant water such as hot tubs, plumbing systems, and large air-conditioning units.
In the United Kingdom, the UK Health Security Agency has recorded a rise in Legionnaires' disease cases in parts of north-west and south-west London. According to Dr Janice Lo, a common source for the London Legionnaires' disease cases has not yet been confirmed. Managers of cooling towers and large water systems in affected London areas have been instructed to treat their systems with high doses of chlorine to eliminate potential contamination.
Around 300 cases of Legionnaires' disease are reported each year in England and Wales. Legionnaires' disease kills one in 10 patients. The UK Health Security Agency notes that Legionnaires' disease is uncommon but can be serious, particularly for older adults, smokers, or people with underlying health conditions.
At this stage, a common source has not yet been confirmed, but we are undertaking further investigations, with partners, that will provide us with more information. Legionella bacteria is widely distributed in the environment and can multiply in large water systems within buildings. It is important that water systems are properly maintained with regular testing and treatment to ensure that bacteria do not multiply and cause a risk to health.