Cyanobacterial bloom occurrence and emergency department visits for asthma or wheeze, Wisconsin, 2017–2019

Environmental Epidemiology
Center for Disease Control and Prevention, Wisconsin Dept of Health Services, United States Environmental Protection Agency, National Aeronautics and Space Administration, Morgan State University
By: , and 

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Abstract

Background: 

Cyanobacterial harmful algal blooms (cyanoHABs) pose risks to human and animal health.

Methods: 

We investigated the relationship between cyanoHABs and asthma or wheeze-related emergency department (ED) visits near three Wisconsin cities (Green Bay, Madison, and Oshkosh) during 2017–2019. CyanoHAB exposure was approximated using the Cyanobacterial Assessment Network remotely sensed satellite indicator of cyanobacterial biomass, a chlorophyl algorithm (ChlBS) aggregated by water-adjacent ZIP Code Tabulation Areas (ZCTA), and distance weighted from the nearest waterbody. Weekly counts of ED visits for asthma or wheeze were aggregated by ZCTA. Poisson generalized linear models estimated the association between the weekly number of ED visits and weekly ChlBS, adjusting for maximum temperature, dewpoint, fine particulate matter (PM2.5), month, and correlation within ZCTA.

Results: 

During 2017–2019, 7,057 ED visits for asthma or wheeze occurred in the study area (42 ZCTAs). Peaks in ChlBS occurred between June and October, with higher values in Lake Winnebago and Lake Mendota compared to Green Bay. ChlBS was not associated with ED visits for asthma or wheeze (adjusted rate ratio = 1.00, 95% confidence interval = 0.99, 1.00), and the presence of onshore winds did not change this result. Monthly aggregations of ED visits and ChlBS showed a monotonic trend between increasing ChlBS and ED visits during July–September.

Conclusion: 

This study demonstrates the utility of remote sensing data in environmental health research. Future studies could explore individual-level exposure and outcomes to refine health risks associated with cyanoHABs.

Suggested Citation

Lavery, A.M., Murray, J., Pennington, A.F., Schaeffer, B., Seegers, B., Hilborn, E.D., Loftin, K., Scroggins, S., and Backer, L., 2026, Cyanobacterial bloom occurrence and emergency department visits for asthma or wheeze, Wisconsin, 2017–2019: Environmental Epidemiology, https://doi.org/10.1097/EE9.0000000000000439.

Study Area

Publication type Article
Publication Subtype Journal Article
Title Cyanobacterial bloom occurrence and emergency department visits for asthma or wheeze, Wisconsin, 2017–2019
Series title Environmental Epidemiology
DOI 10.1097/EE9.0000000000000439
Edition Online First
Publication Date April 23, 2026
Year Published 2026
Language English
Publisher Wolters Kluwer
Contributing office(s) Central Plains Water Science Center
Country United States
State Wisconsin
City Green Bay, Madison, Oshkosh
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