McHenry County Department of Health officials are investigating nine cases of Legionnaires’ disease diagnosed from June 7 to July 1.
The people who became ill were from different locations across the county and range in age from 46 to 82. None of them lived in a public facility, according to county health officials.
“As of now, a common denominator hasn’t been found,” said department spokeswoman Keri Zaleski. “We haven’t identified the source.”
The Illinois Department of Public Health is assisting in the investigation, including “trying to identify commonalities — potential exposures,” said spokeswoman Melaney Arnold.
Legionnaires’ disease is caused by a type of bacterium found in the environment and transmitted by breathing in a contaminated mist or vapor, occurring more often in hot and humid weather, according to health officials. It can become a health concern when it is found in building water systems. In downstate Quincy, Legionnaires’ disease has been cited as a contributing factor in 13 deaths since 2015 of residents of the state-owned Illinois Veterans Home.
Symptoms often start two to 10 days after exposure and include diarrhea, nausea, vomiting, aching muscles, fever and chills. Also common are coughing, shortness of breath, headache or mental confusion.
“Legionnaires’ disease is not known to spread person to person,” Dr. Jennifer Layden, chief medical officer for the Illinois Department of Public Health, said in a statement. “Most healthy people do not get Legionnaires’ disease after being exposed to Legionella bacteria.”
She added that the risk increases for those over 50, current or former smokers, and people who have a chronic disease or a weakened immune system.
In McHenry County, three cases were reported in 2017, and 10 were reported in 2016, according to the state Department of Public Health. Statewide, there were 332 cases in 2017 and 318 cases in 2016; so far this year, 91 cases have been reported in Illinois.
In neighboring Kane County, health department spokesman Tom Schlueter said two cases of Legionnaires’ have been reported this year, in May and June, and 17 cases were reported in all of 2017.
Beacon-News’ Megan Jones contributed.
