“The results from this study and others which we are doing will provide a basis for state and local health departments to develop public educational materials, such as signs describing red tides and explaining what effects people may experience while on the beach.”

The human health effects from Florida red tides are an emerging issue. We know about shellfish poisonings, such as the neurotoxic shellfish poisoning (NSP) that people may get when they eat shellfish contaminated with brevetoxins from Florida red tides. We don’t, however, know much about the human health effects from environmental exposures to marine toxins, including brevetoxins. While there has been considerable local media attention in Florida, there has only been limited scientific work done to assess the human health effects from exposure to aerosolized Florida red tide toxins.

Our paper was the first to document self-reported respiratory symptoms in the presence of measured levels of airborne brevetoxins from a Florida red tide. New methods to quantify brevetoxins in air samples and the application of lung function tests to a field study were used to verify human exposures and assess health effects, respectively.

  Could you summarize the significance of your paper in layman's terms?

For decades there have been anecdotal reports of respiratory effects in people who have been on the beach during Florida red tides. However, in the past, there was not a way to assess exposure, and no one had done a study to quantify the effects from exposure. Although this study was done with a very small number of people, we were able to measure brevetoxins in the air at the same time people were reporting symptoms like cough and itchy eyes, thus linking the exposure and the human health effect.

The Centers for Disease Control and Prevention (CDC) became involved in harmful algal blooms (HABs) in 1997, when there was concern that exposure to an estuarine algae, called Pfiesteria piscicida, made people sick. Since then, working with our state and local public health partners, we have identified other important HAB-related issues. We have expanded our research and cooperative agreement programs to include assessing the public health effects from exposure to other harmful algae, including Florida red tides and cyanobacteria (blue-green algae). CDC investigators are also part of the Red Tide Research Group, a collaboration among researchers from universities, private laboratories, and state and local public health agencies, to address Florida red tides. The activities of the group have been supported by the National Institute of Environmental Health Sciences (NIEHS) grant P01 ES 10594, the Department of Health and Human Services NIH of the NIEHS, and the Florida Department of Health as well as the CDC. I am a co-leader of the group along with Daniel Baden, director of the Center for Marine Science at the University of North Carolina at Wilmington.

The results from this study and others which we are doing will provide a basis for state and local health departments to develop public educational materials, such as signs describing red tides and explaining what effects people may experience while on the beach.

More generally, this is the first work to report that environmental exposures to HABs and HAB toxins are important from a public health perspective and suggests that we should look more closely at other HABs, including marine and freshwater HABs.