Initial Evaluation of the Effects of Aerosolized Florida Red Tide Toxins (Brevetoxins) in Persons with Asthma

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.

The human health effects of Florida Red Tide (FRT) blooms: An expanded analysis

“…Unlike previous work, we did not distinguish among specific types of respiratory illnesses. Hoagland et al (2009) failed to find that FRT blooms could explain variation in ED visits due to asthma, contrasting with other studies that focused specifically on the effects of aerosolized brevetoxins on asthmatics (Fleming et al 2005(Fleming et al , 2007(Fleming et al , 2009; ). The incidence of respiratory illnesses, including and perhaps being driven by asthma cases, has been climbing over the last two decades in Florida, and the potential role that aerosolized brevetoxins play in this growth for populations in coastal locations along the Gulf of Mexico may be important to scrutinize further.…”

“…Human respiratory and digestive illnesses are known to have been caused by exposures to brevetoxins associated with FRT blooms (Kirkpatrick et al 2004(Kirkpatrick et al , 2006(Kirkpatrick et al , 2008(Kirkpatrick et al , 2010Fleming et al 2005Fleming et al , 2007Fleming et al , 2009Fleming et al , 2011Backer 2009;Hoagland et al 2009). These illnesses may exhibit varying severities, leading to increases in costs associated with purchases of over-the-counter medications; self-treatment by asthmatics utilizing prescription pharmaceuticals; visits to outpatient clinics, doctors, and emergency departments; or hospital inpatient admissions.…”

Oceans and human health: Emerging public health risks in the marine environment

“…A number of human illnesses are caused by ingesting seafood contaminated with the natural toxins produced by the HAB organisms (Backer et al, 2005;Backer et al, 2003b;Baden et al, 1995;Fleming et al, 2001). Phytoplankton are the base of the marine food web, and toxins they produce can bio-accumulate and concentrate in organisms higher in the food chain.…”

“…Food poisoning and recreational/occupational exposure to contaminated marine waters have been estimated to cost millions of dollars in health costs and loss of income worldwide (NRC, 1999;DeLong, 2001;Pruss, 1998;Lipp and Rose, 1997;Anderson et al, 2000). At the same time, in some cases possibly due to the increased nutrient loading from human activities and/ or global change, the number, geographic ranges, and variety of harmful algal blooms (HABs) and their toxins appear to be increasing, with impacts on human health indirectly through the food chain as well as directly for coastal marine dwellers (Van Dolah, 2000;Anderson,1994;Backer et al, 2003a,b;Backer et al, 2005;Fleming et al, 2002;Anderson et al, 2000).…”

Brevetoxin-Induced Neural Insult in the Retrosplenial Cortex of Mouse Brain

“…These events result in significant economic losses due to decreased tourism, closing of shellfish beds, and extensive marine life mortality (Bossart et al, 1998;Kirkpatrick et al, 2004;Fleming et al, 2005a).…”