Aerosol brevetoxins

Backer, L.C., Fleming, L.E., Rowan, A., Cheng, Y., Benson, J., Pierce, RH., Zaias, J., Bean, J., Bossart, G.D., Johnson, D., Quimbo, R., Baden, D.G. 2003. Recreational exposure to aerosolized brevetoxins during Florida red tide events. Harmful Algae 2, 19-28. 

The above documents the consequences of toxin ingestion. A few reports suggest that inhalation of aerosolized toxin may cause conjunctival irritation, rhinorrhea, respiratory irritation, and possibly exacerbate or cause symptoms similar to reactive airways disease [168, 169]. Several recent studies have provided additional evidence of adverse respiratory effects, including upper airway irritation and discomfort, decreases in pulmonary function parameters, and worsening asthma symptoms, due to occupational and environmental exposures to aerosolized brevetoxins. 

Backer LC, Kirkpatrick B, Fleming LE, Cheng YS, Pierce R, Bean JA, Clark R, et al. Occupational exposure to aerosolized brevetoxins during Florida red tide events effects on a healthy worker population. Environ Health Perspect 113 644-649, 2005. 

Backer, L. C., Fleming, L. E., Rowan, A. et al.. Recreational exposure to aerosolized brevetoxins during Florida red tide events. Harmful Algae 2, 19, 2003. 

The toxicological consequences of P. brevis red tides are mass mortality of fishes exposed to the red tide toxic shellfish which, if consumed, result in human neurotoxic shellfish poisoning and an irritating aerosol which results from contact with P. brevis cell particles entrapped in seaspray. In all cases, the threshhold levels for intoxication are in the picomolar to nanomolar concentration ranges, implying a specific locus or loci of action for brevetoxins (reviewed in 6). 

Pierce, R.H., Henry, M.S., Blum, PC., Lyons, J., Cheng, Y.S., Yazzie, D., Zhou, Y 2003. Brevetoxin concentrations in marine aerosol Human exposure levels during aKarenia brevis harmful algal bloom. Bulletin of Environmental Contamination... 

Pierce, R., Henry, M.S., Proffitt, L.S., and Hasbrouck, PA. 1990. Red tide toxin (brevetoxin) enrichment in marine aerosol. In Toxic Marine Phytoplankton, ed. Graneli, E., Sundstrom, B., Elder, L., and Anderson, D.M. New York Elsevier, 397-402. 

Most species contributing to algal blooms are harmless however, some of the toxins produced by certain species are highly toxic. Often, the algae and the shellfish that consume them are unaffected. However, further up the food chain, these toxins can be fatal. Man, dolphins, manatees, and reptiles are potentially exposed to aerosolized toxins. Brevetoxins are potent ichthyotoxins and have been responsible for the death of billions of fish over the years. Brevetoxin is absorbed directly across the gill membranes of fish or through ingestion of K. brevis cells. Some of these toxicity differences will depend on the differential susceptibility of fish species to exposure to K. brevis strains involved, toxic components and concentration, stability of extracellular toxins, and exposure routes. Mortality typically occurs at cell concentrations of 2.5 x 10 K. brevis cells per liter, which is often considered to be a lethal concentration. 

The NSP symptoms are nausea, diarrhea, and abdominal pain, in addition to neurological symptoms like paresthesia beginning within minutes to hours after consuming shellfish. In addition, inhalation of aerosols containing brevetoxins may induce reversible upper respiratory syndrome [3]. 

Fleming LE, Kirkpatrick B, Backer LC, Bean JA, Wanner A, Dalpra D, Tamer R, et al. Initial evaluation of the effects of aerosolized Florida red tide toxins (brevetoxins) in persons with asthma. Environ Health Perspect 113 650-657, 2005. 

Taken together, toxicological studies with brevetoxins indicate that the intrinsic potency of bre-vetoxin (PbTx-3) is approximately 5 ng/g and accountable largely by afhnity for binding to the volt-age-gated sodium channel. Integrated toxicity by bath application to hsh or interperitoneal injection to mice yields a reduction in potency of 3- and 40-fold, respectively, likely reflective of differences in uptake and disposition of the toxin. Specialized exposures indicate that PbTx-2 is several-fold less potent orally than interperitoneal in mice and highly potent for localized action on airway constriction by aerosolized exposure to sheep but not for systemic effects in mice or rats. 

Pierce, R. H., Henry, M. S., Blum, P. C. et al., Brevetoxin concentrations in marine aerosol human exposure levels during uKarenia brevis harmful algal bloom. Bull. Environ. Contam. Toxicol. 70, 161, 2003. 

Structure, nomenclature and occurrence Neurotoxic brevetoxins are metaboHtes that are found in the microscopic algae Gymno-dinium breve (syn. Ptychodiscus brevis), which occur in the Gulf of Mexico, the Caribbean region and New Zealand. The extreme algae blooms, for example, along the coast of Florida, creates a so-called red tide, which is a frequent cause of mass fish poisoning. Toxins present in the air as an aerosol may cause temporary inhalation problems when inhaled. 

Characterization of marine aerosol for assessment of human exposure to brevetoxins (article). 

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