Three schools in Illinois' U-46 school district, which covers 11 communities in Cook, DuPage and Kane counties, shut down Wednesday after test results showed "higher than normal levels of Legionella bacteria," the district said
Eastview Middle School, Larkin High School and Gifford Street High School will stay closed Thursday "as the district works to complete the screening process."
The high levels of the bacteria were detected on Wednesday morning in each of the three sites' cooling towers. No exact readings were given, beyond that they were above the 1,000 colony-forming units per millimeter recommended by the Occupational Safety and Health Administration.
Workers disinfected the cooling towers Wednesday and will do the same Thursday "as an additional precautionary step," according to the U-46 district.
The school system gave no indication that anyone who'd frequented any of the affected buildings had gotten sick with Legionnaires' disease.
The situation isn't the first time in recent months that Legionnaires has gotten the attention of Illinois authorities.
About 275 miles southwest of the affected schools, seven residents of the Illinois Veterans' Home in Quincy -- each of whom had underlying conditions -- died amid an outbreak there of Legionnaires' disease, the state public health department said earlier this month
They were among 39 people at the veterans' home who contracted the disease in Quincy, a city of about 40,000 people on the Mississippi River.
As the Illinois Department of Public Health notes, Legionnaires is hardly rare to the state with about 200 cases each year.
"Most are not associated with an outbreak and are considered isolated cases," according to the agency.
Earlier this summer, 12 people in the South Bronx died
and more than 115 people were hospitalized after contracting Legionnaires' disease, according to the New York City health department.
The U.S. Centers for Disease Control and Prevention
estimates between 8,000 and 18,000 people each year in the United States are hospitalized with Legionnaires'.
It doesn't spread from person to person but rather through the air, with those getting it typically coming down with a fever, chills and a cough. Most recover, but 5% to 30% of those who get the disease die, according to the CDC.
And it can be a serious public health situation when it affects people in tight quarters.