The McHenry County Department of Health announced Friday morning that it is investigating a common source of exposure among six of 12 people from McHenry County diagnosed with Legionnaires’ disease in June.
During the investigation, three new cases were found, adding to the nine previously announced. Those previously stricken ranged in age from
46 to 82 years old.
Working closely with the Illinois Department of Public Health and the U.S. Centers for Disease Control and Prevention, the health department determined that six people either lived, worked or spent time within a 1½-mile radius near the intersection of Route 176 and Walkup Road in Crystal Lake.
Activity of the other six people provided no connection. Of the three new cases, two are from outside the county, and one is an out-of-state person who visited McHenry County.
The radius around the Crystal Lake intersection will serve as the case definition for the investigation, which health department community information coordinator Keri Zaleski said is ongoing.
“A lot of good minds have been examining these cases,” Zaleski said. “Coming up with this case definition is very important.”
CDC officials are examining various environmental samples from the area to determine which source specifically contained the Legionella bacterium. Zaleski said this process takes about six weeks.
“Many environmental samples have been collected; however, it is often the case that a single source is never found, which is not surprising or unusual considering that Legionella bacteria are pervasive in our natural environment,” acting health department administrator Joe Gugle said in a news release.
Seen more frequently in hot weather, Legionella bacteria are transmitted through mist or small droplets of water from freshwater environments such as lakes and streams, according to the release.
Zaleski said although people are exposed to the bacteria naturally, it is not a cause for alarm.
Because the 10- to 14-day incubation period for the disease has passed, the chances of future cases cropping up in the county also have decreased considerably, Zaleski said.
Five of the six people in the case definition were admitted to the hospital last month for respiratory issues associated with the disease, Zaleski said. Four of the five have since been released from the hospital, with the remaining person’s condition “improving.”
“Most people exposed to Legionella bacteria will not get sick; however, it can cause severe illness, especially in individuals with risk factors,” health department director of nurses Susan Karras said in a news release. “We are encouraging health care providers to consider Legionnaires’ disease for any individuals presenting with lower respiratory symptoms.”
Symptoms typically begin two to 10 days after exposure and can include coughing, muscle aches, fever, shortness of breath and headaches. Diarrhea and mental confusion also are common.
“Naturally, we are concerned by the pattern demonstrated on the map provided by [the health department]; however, the MCDH and CDC are fully engaged experts at handling matters like this, and we have complete confidence that they will take all necessary steps to safeguard the public,” Crystal Lake Mayor Aaron Shepley said in a statement.
At Duke’s Alehouse & Kitchen at 110 N. Main St. in Crystal Lake, manager Liz Bednarczyk said she is concerned but thankful her establishment has its own water filter for drinking water.
“It takes out the impurities,” she said. “It makes our customers happy.”
McHenry County saw four cases of the disease in 2017, nine in 2016 and three in 2015, Zaleski said. The topic is set to be discussed during a McHenry County Board of Health meeting at 7:30 p.m. Monday at the McHenry County Administration Building in Woodstock.
The health department encourages anyone who is symptomatic to visit their health care provider. For information, visit www.cdc.gov/legionella.
• Northwest Herald reporter Daniel Gaitan
contributed to this report.