Sub Acute and Chronic Health Effects of Aerosolized Red Tide Toxins (Brevetoxins) and Asthma

Introduction: In previous studies, we demonstrated statistically significant changes in pulmonary function testing (PFTs) and reported symptoms for asthmatics before and after 1 hour at the beach with exposure to brevetoxins in Florida red tide (Karenia brevis bloom) aerosols. In this study, we explored the possible longer term health effects over several days and over 7 years from intermittent environmental exposure to brevetoxins in an open cohort of asthmatics age 12 and older.

Methods: In addition to the quantification of their environmental exposure, 147 asthmatic subjects were assessed for their PFTs and reported symptoms before and after 1 hour of exposure to Florida red tide aerosols over both several days and several years of exposed and unexposed studies.

Results: Over the 7 years of studies, as a group, the asthmatics came to the studies with normal percent predicted PFT values standardized for age, gender, race, and BMI. Asthmatics followed for several days after the 1 hour of exposure to the Florida red tide toxin aerosols continued to have significantly increased symptoms and delayed decreased PFTs. The 38 asthmatics participating in only one exposure study reacted statistically significantly more in terms of their pre- vs post-exposure PFTs compared to the 36 asthmatics who came to 4 or more exposure studies. These 36 asthmatics participating in 4 or more exposure studies demonstrated no significant change in their standardized percent predicted pre-exposure PFT values over the 7 years of the study.

Conclusions: These results appear to indicate that asthmatics living in areas with intermittent Florida red tides experience acute and subacute, but not chronic, respiratory effects from intermittent environmental exposure to aerosolized brevetoxins over a 7 year period.