The Michigan Department of Health and Human Services is urging healthcare providers in the state to remain vigilant amid a significant spike in Legionnaires' cases this summer.
The department identified 107 Legionnaires' cases in 25 counties between July 1 and July 14. This figure marks a 569 percent increase from the 16 cases reported in the same period last year and a 169 percent increase from the 41 cases reported in the same period of 2019.
Legionnaires' disease is contracted when water droplets containing Legionella bacteria are inhaled. The department said environmental factors may be contributing to the increase, which is higher than expected for this time of year.
"Recent weather trends including rain, flooding and warmer weather may be playing a role in the rise of reported legionellosis cases this summer," Joneigh Khaldun, MD, the health department's chief medical executive, said in a July 19 news release. "We ask that healthcare providers remain vigilant and test and treat appropriately."
The department is notifying clinicians about the jump in cases and sharing relevant information. Health officials said they have not found a common source of the infections.