Legionnaires’ disease outbreak linked to cooling towers expands from New York to Iowa, Michigan and Westchester
Outbreak linked to contaminated cooling towers has appeared in multiple states, with Marshall County reporting 68 cases and one death as investigators search for the source.
A deadly Legionnaires’ disease outbreak that began in New York City has spread to the Midwest, with Marshall County, Iowa, reporting 68 cases—doubling in just over a week—since the cluster was first announced on Sept. 4.
State health officials say they have not identified a source for the Iowa outbreak and have launched an investigation. They are testing 12 cooling towers in the north-central part of Marshall County, a rural area with about 40,000 residents, as officials believe these large air-conditioning units are the most likely origin of aerosolized water droplets containing Legionella.
Legionnaires’ disease is caused by inhaling aerosolized droplets containing the Legionella bacteria. The bacteria can survive in warm water for hours, depending on humidity and the strain. The illness typically begins with a high fever and a dry cough, followed by shortness of breath, muscle aches, headaches and sometimes gastrointestinal symptoms. In severe cases, infection can spread to the bloodstream, causing sepsis.
In New York, the outbreak that began in Harlem and Morningside Heights sickened 114 people and led to seven deaths earlier this month. Westchester County officials reported two fatalities in White Plains and New Rochelle, and 35 additional cases; officials pointed to hot, humid conditions this summer as a factor in Legionella growth in cooling towers.
In Michigan, two residents at Allegria Village, a Dearborn retirement community, died after contracting Legionnaires’ disease this summer; Wayne County health officials are investigating the source.
Nationwide, up to 18,000 people are hospitalized with Legionnaires’ disease each year in the United States, and about 10% die. The illness is most common from June through October, when cooling towers and air-conditioning systems run at higher levels.
Marshall County Health Department Director Sydney Grewell said the outbreak’s scale is unprecedented for the county and the state, and officials have narrowed the focus to the north-central Marshalltown area, where many residents have visited or traveled to the area and where cooling towers are concentrated.
Because Legionnaires’ disease presents with pneumonia-like symptoms, doctors must test for Legionella to confirm the cause; otherwise many cases are treated as routine pneumonia.