Symptom frequency and exposure to a cyanobacteria bloom in Florida

John S Reif; Nicole Stockley; Kathi Harvey; Malcolm McFarland; Shirley C Gordon; Adam M Schaefer

doi:10.1016/j.hal.2023.102526

Symptom frequency and exposure to a cyanobacteria bloom in Florida

Harmful Algae. 2023 Nov:129:102526. doi: 10.1016/j.hal.2023.102526. Epub 2023 Oct 17.

Authors

John S Reif¹, Nicole Stockley², Kathi Harvey³, Malcolm McFarland², Shirley C Gordon³, Adam M Schaefer⁴

Affiliations

¹ Department of Environmental and Radiological Health Sciences, Colorado State University, 1681 Campus, Fort Collins, CO, 80523, United States. Electronic address: Jreif@colostate.edu.
² Harbor Branch Oceanographic Institute, Florida Atlantic University, 5600U.S. 1N, Ft Pierce, FL 34946, United States.
³ Christine E. Lynn College of Nursing, Florida Atlantic University, 777 Glades Road, Boca Raton, FL 33431, United States.
⁴ Abt Associates, 6130 Executive Blvd Rockville, MD, 20852, United States.

PMID: 37951612
DOI: 10.1016/j.hal.2023.102526

Abstract

This investigation was undertaken to characterize health effects associated with a major bloom of blue-green algae due to the proliferation Microcystis aeruginosa that occurred in Florida in 2018. Cyanobacteria produce multiple toxins, including the potent hepatotoxic microcystins (MCs), that have been reported to cause illness in exposed persons worldwide. Widespread exposure to toxins released by blue-green algae during the 2018 bloom was shown by the presence of MCs in the nasal passages of 95 percent of the individuals studied previously in south Florida (Schaefer et al., 2020). The current analyses were conducted to determine whether self-reported symptoms were associated with activity patterns, direct contact with water, residential, recreational, and occupational exposure. The 125 persons who participated in the initial study reported an average of 4.94 (± 4.87) symptoms. Those reported most commonly included rhinorrhea, sneezing, headache, sore throat and dry cough. Respiratory symptoms were reported by 74%, ocular symptoms by 62%, and gastrointestinal symptoms by 35% of respondents. Residential and recreational exposures were associated with increased risks of respiratory, gastrointestinal, or ocular symptoms in univariate and adjusted multivariable analyses. Residential exposure was significantly associated with increased reporting of dry cough (p = 0.03), dyspnea (p < 0.01) and wheezy respirations (p = 0.04). Among persons reporting gastrointestinal symptoms, nausea (p = 0.02) and abdominal pain (p < 0.01) were significantly associated with residential exposure. Recreational exposure was significantly associated with sore throat and eye irritation. The findings add to the evidence that exposure to cyanobacteria at concentrations encountered during an algal bloom is associated with a diverse array of symptoms and that inhalation of aerosols constitutes an important exposure pathway.

Keywords: Aerosol exposure; Cyanobacteria; Harmful algal blooms (HABs); Public health; Respiratory symptoms.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Cough
Cyanobacteria*
Florida
Harmful Algal Bloom
Humans
Pharyngitis*