Protecting families from contaminated food and water
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Protecting families from contaminated food and water
Posted in Legionella,Legionnaire's disease,Our Blog,Outbreaks & Recalls on September 16, 2025
Case counts of Legionnaires’ disease in Marshall County continue to grow. Health officials still have no confirmed source.
With the number of those sickened with the pneumonia-like illness doubling since the first announcement, residents are no doubt concerned.
How many people have Legionnaires’ disease in Marshall County? Where does Legionnaires’ disease come from? How Do you Know You Have It? Follow along for answers to these top questions!
Since the original announcement brought to you by the Make Food Safe Blog, cases have significantly risen from the 21 cases and one death. These numbers were based on data from September 4, 2025.
On Friday, September 12, Iowa Health and Human Services (Iowa HHS) reported 40 cases. By Sunday, September 14, this has increased to 52.
As of September 15, at least 54 people have been diagnosed with Legionnaires’ disease in Marshall County since August 2025. One person has died.
According to Iowa HHS, cases are clustered in north central Marshalltown.
Legionnaires’ disease is caused by inhaling microscopic Legionella bacteria.
Most of the time these bacteria are found naturally occurring is fresh water sources. Places like lakes, streams, and rivers. When the bacteria make their way into building water systems, they can cause serious illnesses.
What water systems are we talking about. Here are a few.
There are several common sources of Legionnaires’ disease. Even small amount of Legionella bacterial contamination in a place where it shouldn’t be can grow into a huge problem. When that bacteria end up in places where it can become a mist, people can breathe in those tiny droplets containing those germs.
Some of the common sources of Legionella bacteria contamination include:
Marshalltown Water Works, the area’s water treatment manager explains that the town’s treated water is not the likely source of this Legionnaires’ disease outbreak.
“There’s no indication that it’s Marshalltown drinking water that is the cause of this,” said Zach Maxfield, general manager of Marshalltown Water Works.
Maxwell affirms that the water plant rigorously tests for all bacterial pathogens. Including Legionella. The bacterial contamination, he says, is more likely to come from building plumbing system or appliances. Things like air conditioners, boilers, and water heaters.
Cooling towers are the likely source, explains Marshall County Public Health Director Syndney Grewell. In response to this expectation, cooling tower testing in the Marshalltown area is underway. She also urged building owners with cooling towers to disinfect or “shock” them and to take immediate action.
She explains, “as you would think of shocking like a pool that has algae growing in it, to treat those with chemistry and to hopefully kill the bacteria with those chemicals.”
As you can imagine, residents in the Marshall County area are frustrated and concerned about the situation.
Lack of information and a potential source of Legionnaires’ disease in Marshall County continue to evade investigators.
How do you know if you have Legionnaries’ disease?
While symptoms and severity can vary from person to person, and not everyone who is exposed will get sick, there are several common symptoms of Legionnaires’ disease to look out for.
Common symptoms may include:
Other Symptoms may include:
Most people begin feeling sick between two and 14 days after exposure. However, it can take longer for symptoms to appear in some cases.
Most normally healthy individuals will not become infected if exposed to Legionella bacteria. However, certain groups of people are at higher risk of infection.
Higher risk groups include:
So far, more than four dozen people have become sick with Legionnaires’ disease in Marshalltown. At least one person has died so far. Without a known source, more are likely to follow.
If these bacteria are allowed to grow, people can become sick. Some may die.
According to the Center for Disease Control and Prevention (CDC), 1 in 20 people exposed to Legionella bacteria will become sick. Rates of illness are high. And so is mortality rate. An unfortunate 1 in 10 will die from their infection.
Iowa HHS explains that a contaminated water supply can cause Legionnaires’ disease. Treating the water source, maintaining water fixtures, and performing appropriate maintenance on cooling towers are common prevention protocols. Stopping smoking can also reduce the risk of this disease. Respiratory therapy devices should never use tap water (ex: CPAP machine or respiratory treatments).
If you become sick with pneumonia or flu-like symptoms after visiting or staying in the Marshalltown area, you may have Legionnaires’ disease.
If you have become sick with pneumonia-like illness, seek medical attention immediately.
Legionnaires’ disease can be deadly. Do not wait!
Request a diagnostic test for Legionnaires’ disease. Area healthcare providers have been notified of the increased risk. However, if your healthcare provider does not suggest one, tell them about your recent potential exposure risk.
If you test positive for this illness, your local health department will be notified following your diagnosis. Someone may contact you about your illness to ask questions that may help narrow down a source.
The source of this outbreak of Legionnaires’ disease in Marshalltown has not yet been discovered.
For this reason, it is important to make a list of the places that you have been in the weeks prior to becoming sick. The earlier that you can make this list, the more complete and accurate it will be. Have it ready in case you are asked for it.
This information is important, in that it could narrow or expand the scope of this Legionnaires’ disease investigation and help prevent further spread of this deadly infection.
If you have become sick from living, working, or visiting the Marshalltown area, you may have questions. An experienced Legionnaires’ disease lawyer understands your situation and can assist you through the complicated legal process.
If you wish to pursue a legal claim for financial compensation to cover medical expenses, lost work, caring for a loved one, or other burdens associated with Legionnaires’ disease illness, The Lange Law Firm, PLLC has a Legionnaires’ disease lawyer that can help.
Call (833) 330-3663 or send us an email for a free, no obligation consultation.
By: Heather Van Tassell (contributing writer, non-lawyer)