Legionnaires’ Disease Outbreak Investigation

The NC Department of Health and Human Services is investigating the Legionella bacteria outbreak which occurred at the NC Mountain State Fair, Sept. 6–15, 2019 at the Western North Carolina Agricultural Center in Fletcher, NC.

As of Oct. 9, the Division of Public Health has confirmed 134 cases of Legionnaires’ disease or Pontiac Fever in residents of multiple states and North Carolina counties who attended the 2019 NC Mountain State Fair, which took place Sept. 6–15, 2019 at the Western North Carolina Agricultural Center in Fletcher, NC. Eighty-eight people have been hospitalized and two deaths have been reported.

Preliminary findings indicate that people who were diagnosed with Legionnaires’ disease were much more likely to have visited the Davis Event Center while at the fair and much more likely to report having walked by the hot tub displays compared to people who did not get sick. The Davis Event Center is a large building that housed many vendor displays during the fair, including hot tubs. People who were diagnosed with Legionnaires’ disease were also much more likely to have visited during the latter half of the fair compared to people who did not get sick. These findings are from an ongoing study comparing information gathered through surveys of people who were diagnosed with Legionnaires’ disease with similar information gathered from people who attended the fair but did not get sick.

Health officials are also reporting early results from laboratory testing of environmental samples. To date, testing has identified Legionella bacteria in one water sample taken from the Davis Event Center.

“Finding Legionella in one water sample is an important piece of the puzzle, but it does not tell us how so many people were exposed at this event,” said Dr. Zack Moore, State Epidemiologist. “To get Legionnaires’ disease or Pontiac fever, you have to breathe in Legionella in aerosolized water, meaning small droplets like mists or vapors.”

The preliminary epidemiologic and environmental findings suggest that exposure to Legionella bacteria occurred in the Davis Event Center of the WNC Ag Center, particularly near the hot tubs and during the last five days of the fair. Hot tubs are a well-established source of aerosolized water exposure and have been associated with previous Legionnaires’ disease outbreaks nationally and internationally. These results highlight the importance of caring for and maintaining equipment that can aerosolize water.

“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,” said Dr. Moore. “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.”

Public health officials are actively monitoring for new cases of Legionnaires’ disease. As of Oct. 3, there is no indication of an ongoing exposure since the end of the NC Mountain State Fair.

Updated case counts and information about the outbreak are available at https://epi.dph.ncdhhs.gov/cd/legionellosis/outbreak.html.

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