CDPH tracks increase in Legionnaires’ disease cases in July Jul 26, 2021 | Top Stories The Chicago Department of Public Health said Friday it is tracking an increase of Legionnaires’ cases over the past month, following a three-fold increase over recent years.To access this content, you must purchase 1 Year Health News Illinois Subscription or 1 Year Group Subscription - Up to 5 Users, or log in if you are a member.