Study eyes red tide’s effects on humans
SARASOTA — A new study into the neurological effects of red tide on humans could lead to a simple test to determine if an illness is caused by the deadly algae’s brevetoxins.
A significant red tide bloom was visible from the air over Anna Maria Island, Longboat Key, and parts of Sarasota Bay on Wednesday, Aug. 8, 2018. The Herald-Tribune flew over the barrier islands to investigate the harmful algal bloom in a Heli Aviation helicopter. Dead fish speckled the discolored water near Bradenton Beach. [Herald-Tribune staff photo / Carlos R. Munoz]
Nearly a dozen researchers from the Roskamp Institute in Sarasota have begun a study with a $400,000 federal grant from the National Institute of Environmental Health Sciences to advance their work on brain health.
The nonprofit group has studied the causes and potential cures for neurodegenerative and neuropsychiatric disorders such as Alzheimer’s Disease, multiple sclerosis and Gulf War Illness. Their work has led to novel treatments clinically tested in Europe and the U.S.
More than 400 volunteers in Sarasota and Manatee counties are being sought for the study, according to Roskamp Executive Director Dr. Michael Mullan, one of the team leaders in the Florida red tide project and the executive director of the Roskamp Institute.
The grant was made possible in part by legislation sponsored by Congressman Vern Buchanan to study the impact of red tide. Ten doctors from the Roskamp Institute and members of Mote Marine Laboratory will participate in the study.
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"People need to know if exposure causes long-term damage,” Buchanan said in a news release. “This grant of more than $400,000 will allow Roskamp to determine if human exposure to the red tide neurotoxin called brevetoxin causes brain impairment or other problems.”
Currently, brevetoxins, a neurotoxic compound produced by the dinoflagellate Karenia brevis, can cause fish to swim in circles and loose equilibrium before ultimately dying.
Hundreds of apex marine mammals, like dolphins, manatees and sea turtles, who feed on fish and seagrass poisoned by red tide, became sick and died during the last red tide episode.
Southwest Florida residents who went to the beach during the red tide bloom anecdotally reported flu-like symptoms.
“Hopefully, our research will show that there is no link between the Florida red tide brevetoxin exposure and an increase of neurological disorders,” Mullan says. “However, when you see metric tons of marine life being killed in a few weeks, you realize how powerful the toxin is, and knowing that some of the effects of exposure can be long-lasting in other species, it makes sense to make sure that something similar is not happening in the human population — particularly in vulnerable populations.”
Barbara Kirkpatrick, executive director for the Gulf of Mexico Coastal Ocean Observation System, participated in the only known long-term review of “Florida Red Tide and Human Health Effects” from 2001 to 2011. It detected varying effects of red tide in all of the participants.
Healthy volunteers had upper airway symptoms — watery eyes, runny nose and a cough — but there was no change in their lung function. Aerosolized toxins did not enter the lower airways of healthy patients.
Asthmatics over age 12 had upper and lower respiratory issues, including decreased lung function for about three to four days after exposure. The subgroups that appeared to have reacted the most were those reporting recent use of asthma medications.
About 10 to 20 percent of brevetoxins are small enough to enter the lungs, the study stated. Aerosols traveled as much as a mile inland from coastal areas during active red tide blooms with strong onshore winds.
Kirkpatrick is a key member of the present study. She and her colleague’s work suggests that an excess of emergency room admissions for neurological complaints happened during Florida’s major red tide blooms between 2005 and 2009.
According to a news release, the present study requires volunteers to submit blood and urine samples to measure brevetoxin and antibody levels. Comparing the levels of brevetoxin and antibodies with the levels of neurological complaints will shed light on whether Florida red tide brevetoxin exposure can trigger neurological conditions and whether immune responses are likely protective or make symptoms worse.
The Roskamp Institute will look for ways to understand and treat any neurological disorders caused by red tide.
“We study brain diseases and we are interested in the short-term and long-term effects of inflammation on the rain,” Mullan said. “We are interested to know if in the short term there is a relation between the amount of brevetoxin in your blood and neurological effect when people have symptoms.”
Mullan says his team is seeking volunteers who live within five miles of the beach and as far east as Lakewood Ranch for the study. They will be compensated for travel expenses.
“We are funded and ready to go,” he said. “As soon as people want to come in and see us, that would be great.”
Individuals interested in participating in the study can contact Megan Parks at 942-256-8018, ext. 3008.
“One of the big drivers of brain disease is inflammation,” said Mullan, noting brevetoxins can cause inflammation in other organs. “We’ve seen that and known that for years. Anything that contributes to inflammation in the brain is generally bad for Alzheimer’s Disease. It makes sense to study this.”
Project team team leader Dr. Laila Abdullah added that, “One critical observation is that brevetoxin does not affect everyone equally — some people are relatively unaffected by it, whereas others get severe symptoms very easily. We are very interested to know the reason for this, and so we are examining the role of the immune system and looking at differences in neurological effects between those that have severe symptoms versus those that do not."
Kirkpatrick said the study is ambitious by asking for 400 participants.
“I know people don’t want to hear this, but they’re going to need a red tide exposure,” she said, noting it is a two-year study. “I am confident that Mother Nature will cooperate but not necessarily on the timeline that we set.”
One of the things Kirkpatrick said her previous research failed to do was come up with a biomarker of exposure — work that could lead to a test for red tide in humans.
“We tried in 2011 and weren’t successful in getting something specific enough,” Kirkpatrick said. “The Roskamp people are experienced at method development. We are hoping they can come up with this biomarker for us.”