Evaluation of Syndromic Surveillance Data for Studying Harmful Algal Bloom-Associated Illnesses — United States, 2017–2019

Abstract

What is already known about this topic? Harmful algal and cyanobacterial blooms are large colonies of algae or cyanobacteria that can harm humans, animals, and the environment. What is added by this report? National syndromic surveillance data identified 321 emergency department visits related to harmful algal bloom exposure during 2017-2019. Frequency of these visits was highest during warmer months. What are the implications for public health practice? Syndromic surveillance data are useful for studying the extent of harmful algal bloom-associated illness. Increasing awareness so that more patients know to mention harmful algal bloom exposures and more physicians know to ask about them could improve documentation of health effects and enable further use of health records for health studies.