Drug overdose treatment for humans can detox turtles poisoned by red tide, study shows

Leatherback sea turtle
Leatherback sea turtle. Credit: Public Domain

A detox therapy used to treat overdoses in humans may help save endangered sea turtles from red tide poisoning.

Injecting a fat solution in sea that have been exposed to can eliminate toxins from the bloodstream in just 24 hours, research by the Loggerhead Marinelife Center showed. Currently, treatments involve giving the turtles diuretics to force their kidneys to filter the toxins out of the body. That's a slow process in which full recovery can take up to three months, lowering the chances of survival and successful return to the wild.

"Red tides are becoming more frequent, and we're going to see more strandings of threatened turtles," said Dr. Justin Perrault, director of research at Loggerhead Marinelife Center in Juno Beach. "This treatment could help us get them back into their environment faster, which is important for their populations."

As red starts to bloom again in Florida's southwestern coast, veterinarians are hoping that the intravenous lipid emulsion therapy will help save more turtles from killer toxins that cause neurological problems. It's the first time the treatment, which has been used in humans and mammals for decades, is being tested on sea turtles. Scientists in Florida have tested nearly 30 turtles among loggerheads, green and Kemp's ridley, and saw symptoms disappear in 24 hours.

Red tide is caused by an algae species called Karenia brevis that releases harmful neurotoxins, known as brevetoxins, into the water. Brevetoxins bind to fats and are often found in fatty organs, such as the liver, in affected turtles. The toxins can cause neurological symptoms as spasms, muscle tremors and disorientation, which can lead to mass strandings and death. In high dosages, brevetoxins can lead to seizures in sea turtles.

By injecting a fatty emulsion directly into the animals' blood stream, scientists are giving toxins something else to bind to other than the turtles' organs.

"It acts as a trap, capturing the drug before it gets into the nervous system," said Dr. Kelly Diehl, senior director of science at Morris Animal Foundation, which funded part of the lipid emulsion turtle research. Another benefit of this therapy is the quick recovery time. In general, the longer the animal is in treatment, outside of its habitat, the lower the chances of survival once it's released back into the ocean, she said.

On average, around 600 turtles are stranded from red tide exposure every year, according to the foundation. So far in October, the Florida Fish and Wildlife Conservation Commission documented 20 stranded sea turtles in Collier County and 18 in Lee County. Five of these turtles were found alive while the rest were dead. On average, the two counties would typically have about eight to 10 stranded sea turtles in October.

"We suspect about 75% of the stranded sea turtles found in Collier County and Lee County during October of this year are attributable to red tide," said FWC sea turtle biologist Allen Foley.

A record number of sea turtles—about 590—died in the catastrophic red tide event of 2018, which fouled beaches on both coasts with dead fish and chased away tourists. In addition to producing neurological effects on marine animals that are in the water, waves can release toxins into the air, which can cause respiratory infections in people with conditions like emphysema or asthma. Toxins can also accumulate in oysters and clams, which make them toxic for humans to eat, according to the FWC.

The latest red tide report from the FWC showed high concentrations of the toxic algae blooms in Lee and Collier counties. Red tide toxins were not observed along the east or northeast coasts of the state, the FWC said. Fort Myers Beach, Naples Beach, Bonita Springs and Sanibel Island showed medium to high concentrations of the organism. The harmful algae were not found in either the north or east coasts of Florida.

While red tide blooms occur naturally in the Gulf of Mexico, explosions in growth can lead to hazardous conditions for both humans and marine life. A red tide in 2018 killed wildlife throughout Florida's southwest coast and left beaches littered with dead fish, , manatees and even a whale shark. Red tides have been documented in the Gulf Coast since the 1840s but the most recent event over the course of 16 months from November 2017 until February 2019 was the first since 2007 to impact Florida's southwest, northwest, and east coasts simultaneously. It was the worst red tide bloom since 1953.

Scientists say coastal pollution feeds the blooms, making them worse.


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Citation: Drug overdose treatment for humans can detox turtles poisoned by red tide, study shows (2019, October 28) retrieved 7 December 2019 from https://phys.org/news/2019-10-drug-overdose-treatment-humans-detox.html
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