Florida scientists study health effects from exposure to toxic algae

Toxic blue-green algae is seen in the Caloosahatchee River in Fort Myers, Fla., in 2018. Photo by Brian Cousin/Harbor Branch Oceanographic Institute
Toxic blue-green algae is seen in the Caloosahatchee River in Fort Myers, Fla., in 2018. Photo by Brian Cousin/Harbor Branch Oceanographic Institute

ORLANDO, Fla., Feb. 20 (UPI) -- People in Florida have tested positive for exposure to blue-green algae toxins just from breathing air around it, and scientists are ramping up studies into how the blooms affect long-term health.

Public awareness that blue-green algae can be deadly has grown in recent years due to fish kills around algae blooms and even pet deaths. No human deaths have been reported, but algae-related illness has driven people to doctors.


Florida Atlantic University and three other research schools have launched studies this year to test people who live near the coast for long-term exposure to algae toxins.

The blooms happen around the state and nationwide, said Adam Schaefer, an epidemiologist at the university's Harbor Branch Oceanographic Institute in Fort Pierce.

"It's important we do this research carefully and get that information into the hands of folks in the communities that are affected."


To accomplish that goal, residents on Florida's Atlantic and Gulf coasts are getting nasal swabs and urine and blood tests to detect signs of the algae toxins -- called microcystin in blue-green algae and brevetoxin in red tide algae.

Schaefer said scientific studies have shown for years that the toxins found in algae are associated with liver damage and liver disease, along with skin rashes, headaches and troubled breathing.

"We really don't have good data documenting the impact over a longer term and comparing that to what is going on in the environment," he said.

Schaefer conducted preliminary tests on human secretions during a severe algae bloom in summer 2018. That research found microcystin in the nasal passages of 95 percent of the participants. Of 86 urine samples taken, microcystins were found in three.

The first official results from that study were published in the February issue of the online journal Harmful Algae. Schaefer developed the urine tests for the toxins in conjunction with the U.S. Centers for Disease Control and Prevention.

Some of those tested who had the toxins in their nose reported no direct contact with contaminated water. Schaefer then concluded that the toxins entered noses after becoming airborne.


Despite the conclusive results of that study, Schaefer said much still is not known about the impact on human health.

"Just because it's in the nose doesn't mean it's being absorbed in the body," he said. "The urine shows us what is being expelled from the body. We're really starting from scratch."

Unanswered questions include "how the body absorbs the toxin, the minimum safe distance for persons from blooms and potential health effects of exposure," Schaefer said.

"It's important to validate concerns with real hard facts," said Howard Voss, chief executive officer of the Volunteers in Medicine Clinic in Stuart, Fla., which works with FAU to conduct human tests.

"We all know blue-green algae is an eyesore disturbing the water and recreation opportunities," Voss said. "But does it cause disease? Is it having only having an effect on fishing and boats and vacations, or is it really causing long-term health damage?"

The study reported that nasal microcystin concentrations generally were highest during severe algae blooms, but that further research was needed to define the correlation between health and several blooms.

Schaefer said the results of the long-term study could be used to warn people to stay indoors or away from the coast during heavy blooms.


Other schools that are studying long-term algae impact with the new state funding are Florida Gulf Coast University, the University of Miami and the University of Florida.

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