Health officials have said an outbreak of Legionnaires’ disease in Marshall County may be linked to cooling towers.
The state has confirmed 34 cases of Legionnaires’ disease in the county since the end of August, resulting in the death of one person.
The disease is a severe respiratory infection that’s caused by inhaling water droplets containing the Legionella bacteria. It is not contagious and is not caused by drinking contaminated water, which would instead cause stomach irritation, health officials said.
State epidemiologist Matthew Donahue told the Marshall County Board of Supervisors this week that state and local officials have been investigating the outbreak since the end of August, and while they aren't certain, evidence points to local cooling towers as the possible source of the outbreak.
"Because of how wide it appears to be spread, because of the calls we've made to patients so far, that seems like the most likely answer to how this has all started," he said.
Cooling towers use evaporation to get rid of excess water in buildings that have large equipment, like air conditioning units.
The stagnant water in the towers can be attractive to the bacteria, Sydney Grewell, the director of the Marshall County Public Health Department, told supervisors.
"In Iowa, we tend to go hot and cold from one week to another, and that produces it sometimes as well," she said. "If you have your cooling tower on, and it sits stagnant for a couple days, that gives perfect breeding ground for that bacteria to grow."
Officials are testing nine cooling towers in the area and asking that all be disinfected, she said.
Most people are exposed to the Legionella bacteria, but the vast majority experience no symptoms, Donahue said. People who are older, smokers or have underlying conditions are at highest risk for getting severely ill.
The state sees between 30 and 90 cases of Legionnaires' disease each year, but officials started investigating the Marshalltown area as a potential cluster after several cases were identified there late last month, he said.
People who have severe respiratory symptoms in the area should go get tested for the bacteria, which can be treated with antibiotics, Donahue said. It can take anywhere from two to 14 days for people to experience symptoms after exposure.
"The message for general public is, if you're in Marshalltown now, you have a cough and fever, shortness of breath, you think you might have a respiratory infection or pneumonia, to talk to your doc and tell them about Legionella," he said.
