NAPA COUNTY, CA — As an investigation continues into the source of a Legionnaires’ disease outbreak in Napa County, authorities have preliminarily identified high levels of Legionella bacteria in a sample taken from an air conditioning tower at a Napa hotel, the county of Napa said late Wednesday.
Since July 11 in Napa County, there have been 12 cases of Legionnaires’ disease, a severe form of pneumonia caused by the bacteria Legionella, which grows in warm water. Aerosolized water can come from cooling towers — air-conditioning units for large buildings — hot tubs, cooling misters, decorative fountains, and plumbing systems.
All 12 people sickened in Napa County have been hospitalized and one person has died. Three people remained hospitalized this week.
“Napa County Public Health has been working closely with the California Department of Public Health and Centers for Prevention and Disease Control to investigate and remedy sources of Legionnaires’ disease cases in Napa County,” county officials said in a news release. “Testing human-made water sources, such as cooling towers and decorative fountains, preliminarily identified high levels of Legionella bacteria in a sample taken from a cooling tower at Embassy Suites Napa Valley, located on California Boulevard in the City of Napa.”
The cooling tower at Embassy Suites has since been taken offline, which mitigates any ongoing risk to public health, the county said. Napa County Public Health was continuing its investigation to identify any additional sources that might contain the Legionella bacteria in unsafe amounts.
“Our joint investigation team continues to work with Embassy Suites staff to remedy the source of exposure,” said Dr. Karen Relucio, Napa County Health Officer. “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.”
Those at higher risk include people 50 and older, cigarette smokers, and people with chronic lung disease or compromised immune systems. The Napa County resident who died after contracting Legionnaires’ disease was over 50 and had risk factors for severe disease.
“As part of this ongoing investigation, to date none of the 12 residents diagnosed with Legionnaires’ disease have been identified as having stayed or visited this Embassy Suites hotel,” the county said.
People can get Legionnaires’ disease by breathing in aerosolized (small droplets) water containing Legionella bacteria. Legionnaires’ disease is not spread from person to person and can be treated with antibiotics when caught early.
Public health officials urged Napa County residents, and people living or working in the City of Napa, who have flu-like symptoms, cough, fever or difficulty breathing should contact a healthcare provider as soon as possible.
“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,” Relucio said. “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.”