Harmful Algal Bloom Statistics

Human Cases

From 2014 to 2023, MDH received reports of 12 HAB-associated illnesses: 3 suspect cases and nine 9 cases. Case statuses are determined based on the CDC OHHABS Case Definitions. The median number of cases annually was 1 (range, 0 to 4). The median age of cases was 11 years (range, 2 to 38 years). All cases were exposed to HABs during May through August, with 50% of cases exposed in July. 

Animal Cases

From 2014 to 2023, MDH received reports of 18 animal HAB-associated illnesses: 7 suspect cases, 10 probable cases, and 1 confirmed case. Case statuses are determined based on the CDC OHHABS Case Definitions. The median number of animal cases annually was 1.5 (range, 0 to 5). All animal HAB-associated illness cases were dogs. All animal cases were exposed to HABs during March through September. Thirteen (72%) cases died as a result of their illness. 

Charts, Graphs, and Maps

	HAB-Associated Illness Cases in Minnesota by Year, 2014-2022 (PDF) Bar graph of HAB-associated illness cases in Minnesota per year by illness type.
	Human HAB-Associated Illness Cases in Minnesota by County of Exposure, 2014-2023 (PDF) Map of the total number of human HAB-associated illness cases in Minnesota from 2014 to 2023 by county of exposure.
	Animal HAB-Associated Illness Cases in Minnesota by County of Exposure, 2014-2023 (PDF) Map of the total number of animal HAB-associated illness cases in Minnesota from 2014 to 2023 by county of exposure.
	Animal and Human HAB-Associated Illness Cases in Minnesota by County of Exposure, 2014-2023 (PDF) Map of the total number of animal and human HAB-associated illness cases in Minnesota from 2014 to 2023 by county of exposure.