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One Dead And 11 Sick From Legionnaires' Disease Outbreak In Californian City

Legionella bacteria have been found in one hotel's water cooling tower, but none of the infected have stayed there


Tom Hale

Senior Journalist

clockAug 9 2022, 15:22 UTC
A water tank sits on top of a high-rise hotel.
Outbreaks of Legionnaires’ disease can often occur in buildings that store water for a large number of people, like hotels. Image credit: alongkorn chareonphol/

As if California’s water woes couldn’t get worse, a Legionnaires’ disease outbreak has hit the city of Napa County. So far, one person has died and at least 11 others have fallen sick, including three people who required medical attention at hospital, according to Napa County Public Health. 

Working with the California Department of Public Health and the CDC, local public health authorities took samples from a bunch of human-made water tanks in the Napa area. They found high levels of Legionella bacteria in a cooling tower at Embassy Suites Napa Valley hotel on California Boulevard. The cooling tower has since been shut off to protect the public.


Oddly, however, none of the 12 individuals infected with the disease had stayed at the hotel, suggesting the investigation still has not reached the root of the problem.

“Finding Legionella in one water sample is an important piece of the puzzle, but we must continue to investigate other cooling towers and water sources in the outbreak area, as it is common to find more than one source,” Dr Karen Relucio, Napa County Health Officer, said in a statement.

Legionnaires’ disease is a lung infection caused by the bacteria Legionella, which thrives in large warm water tanks. 

People are typically infected by aerosolized water sprayed from cooling towers, air-conditioning units, hot tubs, cooling misters, decorative fountains, and plumbing systems of large buildings. 


As such, outbreaks of Legionnaires’ disease can often occur in buildings that store water for a large number of people, like hotels. The bacteria Legionella was named after a severe outbreak in 1976 involving hundreds of people who attended a convention of the American Legion at the Bellevue-Stratford Hotel in Philadelphia.

Symptoms of Legionnaires’ disease are similar to other types of pneumonia, involving an unpleasant mix of a cough, shortness of breath, fever, achy muscles, and headaches. The bacteria Legionella can also cause a mild illness known as a Pontiac fever that doesn’t involve pneumonia and people typically recover from quickly. 

You can reduce the risk of catching Legionnaires’ in your own home by flushing taps and showerheads if they haven’t been used recently, plus cleaning any devices that could contain water, such as humidifiers, respiratory therapy devices, showerhead aerators, water heaters, hot tubs, etc.

"Although Legionnaires’ disease is a rare infection, this is a reminder that the bacteria that cause it are common in nature and can be found in man-made water systems," added Dr Relucio. "This means it’s very important for owners and managers of water systems that can create aerosols to take steps to prevent Legionella from growing and spreading in water systems."


Beyond concerns about Legionnaires’ disease, California's wider water supply is stuck in a chokehold thanks to a deepening drought, forcing the price of water to reach an all-time high in the state. 

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