Michigan Department of Health and Human Services | Susan J. Demas
The Michigan Department of Health and Human Services (DHHS) and local health departments are investigating a recent spike in Legionnaires’ disease cases across the state.
The DHHS announced Monday that in the 13 days between July 1 and Wednesday, 107 cases of the respiratory infection were reported in 25 counties — representing a 569% increase from the same period in 2020 and a 161% increase from the same period in 2019.
The newest confirmed cases are centered in Southeast Michigan, with 19 in Wayne County, 17 in Oakland County, 17 in the city of Detroit and 15 in Macomb County.
Aside from Wayne, Oakland and Macomb counties, 21 additional counties confirmed at least one case of Legionnaires’ disease in the 13-day timeframe. Saginaw County reported five cases; Genesee and Ingham counties reported four each; Shiawassee and Monroe counties reported three each; Kalamazoo, Livingston, Ottawa and St. Clair counties reported two each; and 12 counties reported one each.
Legionnaires’ disease is one of two forms of legionellosis respiratory infections caused by Legionella bacteria. The disease causes symptoms including fever, cough and pneumonia.
Cases most commonly occur in the summer and early fall due to environmental factors like heat and rainfall. However, the DHHS notes that this year’s increase is higher than usually expected this time of year.
“Recent weather trends including rain, flooding and warmer weather may be playing a role in the rise of reported legionellosis cases this summer,” said Dr. Joneigh Khaldun, DHHS chief medical executive and chief deputy director for health.
“We want everyone to be aware of Legionnaire’s disease, especially if they may be at higher risk for illness and we ask that healthcare providers remain vigilant, and test and treat appropriately.”
DHHS and local health departments are requesting that health providers keep the possibility of Legionnaires’ in mind when treating patients that present with pneumonia and risk factors for the infection.
Individuals who are over age 50, are current or former smokers, have chronic lung disease, have weakened immune systems from disease and/or take immunosuppressant drugs have a higher risk of getting sick after exposure to Legionella.
Since transmission of Legionnaires’ occurs when mist or vapor containing the bacteria is inhaled, a higher chance of exposure exists for individuals who have recently traveled with an overnight stay, have recently stayed in a healthcare facility, have have exposure to hot tubs (stagnant waters present an ideal bacterial growth environment) and/or have had exposure to settings with recent repairs or maintenance work to the plumbing.
Legionnaires’ disease does not spread person to person and most healthy individuals do not become infected after exposure to the bacteria.
DHHS says that so far, no common sources of infection have been identified.
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