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Lora E. Fleming,^1,2 Barbara Kirkpatrick,³ Lorraine C. Backer,⁴ Judy A. Bean,⁵ Adam Wanner,² Dana Dalpra,³ Robert Tamer,⁵ Julia Zaias,^1,2 Yung Sung Cheng,⁶ Richard Pierce,³ Jerome Naar,⁷ William Abraham,^1,2 Richard Clark,⁸ Yue Zhou,⁶ Michael S. Henry,³ David Johnson,⁸ Gayl Van De Bogart,¹ Gregory D. Bossart,^1,9 Mark Harrington,¹⁰ and Daniel G. Baden⁷

¹National Institute of Environmental Health Sciences Marine and Freshwater Biomedical Sciences Center, University of Miami Rosenstiel School of Marine and Atmospheric Sciences, Miami, Florida, USA; ²University of Miami School of Medicine, Miami, Florida, USA; ³Mote Marine Laboratory, Sarasota, Florida, USA; ⁴National Center for Environmental Health, Centers for Disease Control and Prevention, Atlanta, Georgia, USA; ⁵Children's Hospital Medical Center and University of Cincinnati, Cincinnati, Ohio, USA; ⁶Lovelace Respiratory Research Institute, Albuquerque, New Mexico, USA; ⁷Center for Marine Science Research, University of North Carolina at Wilmington, Wilmington, North Carolina, USA; ⁸Florida Department of Health, Tallahassee, Florida, USA; ⁹Harbor Branch Oceanographic Institution, Fort Pierce, Florida, USA; ¹⁰Twin Cities Hospital, Niceville, Florida, USA

Abstract
Florida red tides annually occur in the Gulf of Mexico, resulting from blooms of the marine dinoflagellate Karenia brevis. K. brevis produces highly potent natural polyether toxins, known as brevetoxins, that activate voltage-sensitive sodium channels. In experimental animals, brevetoxins cause significant bronchoconstriction. A study of persons who visited the beach recreationally found a significant increase in self-reported respiratory symptoms after exposure to aerosolized Florida red tides. Anecdotal reports indicate that persons with underlying respiratory diseases may be particularly susceptible to adverse health effects from these aerosolized toxins. Fifty-nine persons with physician-diagnosed asthma were evaluated for 1 hr before and after going to the beach on days with and without Florida red tide. Study participants were evaluated with a brief symptom questionnaire, nose and throat swabs, and spirometry approved by the National Institute for Occupational Safety and Health. Environmental monitoring, water and air sampling (i.e., K. brevis, brevetoxins, and particulate size distribution) , and personal monitoring (for toxins) were performed. Brevetoxin concentrations were measured by liquid chromatography mass spectrometry, high-performance liquid chromatography, and a newly developed brevetoxin enzyme-linked immunosorbent assay. Participants were significantly more likely to report respiratory symptoms after Florida red tide exposure. Participants demonstrated small but statistically significant decreases in forced expiratory volume in 1 sec, forced expiratory flow between 25 and 75%, and peak expiratory flow after exposure, particularly those regularly using asthma medications. Similar evaluation during nonexposure periods did not significantly differ. This is the first study to show objectively measurable adverse health effects from exposure to aerosolized Florida red tide toxins in persons with asthma. Future studies will examine the possible chronic effects of these toxins among persons with asthma and other chronic respiratory impairment. Key words: asthma, brevetoxins, COPD, harmful algal blooms (HABs) , Karenia brevis, red tides, sensitive populations, spirometry. Environ Health Perspect 113:650-657 (2005) . doi:10.1289/ehp.7500 available via http://dx.doi.org/ [Online 10 February 2005]

This article is part of the mini-monograph "Aerosolized Florida Red Tide Toxins (Brevetoxins) ."

Address correspondence to L.E. Fleming, c/o Department of Epidemiology and Public Health, University of Miami School of Medicine, 1801 NW 9th Ave., Highland Professional Building, Suite 200 (R 669) , Miami, FL 33136 USA. Telephone: (305) 243-5912. Fax: (305) 243-3384. E-mail: lfleming@med.miami.edu

This study could not have been performed without the help of numerous volunteer investigators, including T.C. Fleming, C. Fleming, M. Johnson, W. Quirino, M. Friedman, D. Squicciarini, L. Pitman, and T. Pitman (University of Miami National Institute of Environmental Health Sciences Center) ; J. Horton, J. Howell, R. Sabogal, C. Bell (Centers for Disease Control and Prevention) ; P. Stack, G. Kirkpatrick, and C. Higham (Mote Marine Laboratory, Sarasota, FL) . We also thank A. Weidner from the University of North Carolina at Wilmington for her help with the enzyme-linked immunosorbent assay analysis. Environmental monitoring was performed with help from S. Campbell (University of North Carolina at Wilmington) ; T. Blum, S. Hamel, B. Turton (Mote Marine Laboratory) ; D.A. Kracko, J. McDonald, and C.M. Irvin (Lovelace Respiratory Research Institute) . We also thank the Mote Marine Laboratory, Sarasota County Parks and Recreation Department, the Coquina and Helmseley hotels, and all our volunteer participants and their families in Sarasota, Florida.

This research was supported by National Institute of Environmental Health Sciences (NIEHS) grant P01 ES 10594 and a Minority Supplement to the P01 also from the NIEHS, as well as by the Centers for Disease Control and Prevention, the Florida Harmful Bloom Taskforce, and the Florida Department of Health.

The authors declare they have no competing financial interests.

Received 2 August 2004 ; accepted 19 January 2005.