June 13, 2004, Updated September 13, 2012

From the chilly waters of the Atlantic Ocean to the blue surf of the Pacific, swimmers and surfers are getting ready for a long, hot – and wet – summer. One of the few negative aspects to spending days luxuriating in the sea is the annual appearance of that enemy of ocean swimmers – jellyfish.

But now, Israeli researchers have created a lotion that repels the sharp stings of jellyfish, just as sunscreen keeps away the dangerous rays of the sun.

SafeSea, an over-the-counter lotion sold as a jellyfish repellent by Israeli company Nidaria Technology seems to render the beachgoer’s nemesis powerless – usually.

In an American study that recently exposed two dozen volunteers’ arms to jellyfish tentacles, researchers found that the lotion kept all but one arm from becoming red and swollen. And only a few participants felt discomfort in the lotion-protected arm.

“It didn’t completely inhibit the stings, but it came pretty darn close,” reported Alexa Kimball, MD, MPH, an assistant professor of dermatology at Stanford University School of Medicine, who directed the study. The study appears in the June issue of the journal Wilderness and Environmental Medicine.

The Stanford researchers borrowed sea nettles from the Monterey Bay Aquarium to do the testing on volunteers in a research clinic at Stanford Hospital. These nettles are known to sting swimmers, surfers and boaters worldwide, including along the Chesapeake Bay and the coastlines of Florida and California. Their stings cause a burning sensation, as well as swelling, pain and occasional blisters.

Study collaborators at the Bert Fish Medical Center in Florida also tested a more dangerous species known as the box jellyfish or sea wasp, which is prevalent along the Florida and Texas coasts and around the Gulf of Mexico. The stings from these jellyfish can cause severe reactions and can be life-threatening, particularly in young children.

“This certainly suggests the cream is going to help,” said Kimball, who is director of clinical trials in dermatology. “Even if it doesn’t offer 100-percent protection, I would rather have some protection over none.”

According to Nidaria Technologies CEO Chen Porat, who runs the company from from a kibbutz headquarters on the Sea of Galilee, SafeSea is based on the research and findings of Dr. Amit Lotan, SafeSea’s founder and chief scientist.

“Amit got interested in the field when he went swimming in the Mediterranean and started to feel like he got stung by a jellyfish, but there were no jellyfish around. It aroused his interest,” Porat told ISRAEL21c.

“He did his PhD at the Technion on the toxin delivery system of jellyfish. Jellyfish, sea lice, sea nettle, coral, sea anemone and other organisms, which belong to the phylum cnidaria, are all equipped with similar stinging cells, and Amit was basically the first researcher to do a thorough investigation into the mechanism on a biochemistry level.”

Lotan’s findings at the time were published in Nature magazine, as well as leading marine biology journals in the mid-90s.

“Some of his research has been sponsored by the UN – there have been real problems with jellyfish not only in the Mediterranean but in the Adriatic Sea, and other places. It was turning into a problem for tourism, and a global problem,” said Porat.

In his research, Lotan noticed that clownfish – of Finding Nemo fame – do not get stung by jellyfish. While spending three years in California after obtaining his PhD, Lotan isolated the chemical that seemed to protect the little orange and white fish and incorporated the substance into a sunscreen solution. When he returned to Israel in the late 90s, he founded Nidaria to develop the revolutionary sunscreen.

SafeSea was introduced in Israel in the summer of 2000, and began being marketed worldwide in 2002. But until now, there had been no published studies on its effectiveness, according to the study’s lead author Kimball.

Kimball and her colleagues – including Lotan – exposed 12 adults to the tentacles of the sea nettle, a type of jellyfish commonly found along the U.S. coast, in places like Florida, the Chesapeake Bay in Maryland, and in a large area of the Pacific.

Another 12 volunteers endured the tentacles of the box jellyfish, a creature with a particularly nasty sting that can even be life-threatening in some cases. The sea animal is found in the Gulf of Mexico area, and along the coasts of Florida and Texas, according to the study authors. Each volunteer had one arm coated with the inhibitor lotion and the other arm with regular sunscreen before having the tentacles placed on them.

Kimball’s team found that none of the inhibitor-treated arms showed signs of irritation after tangling with the sea nettle tentacles, while all of the arms shielded with only sunscreen developed a rash. Two people complained of “minimal discomfort” in the treated arm, while all said the sunscreen-only arm was painful, the researchers report.
In the box jellyfish group, one treated arm showed a skin reaction, and three volunteers reported discomfort in their inhibitor-shielded arms.

The ingredients of the cream are proprietary, but Kimball said she believes the inhibitor works in several ways. For one, it naturally repels water, making it difficult for the jellyfish to make contact with the skin, she said. It also contains a mixture of sugar and protein that is similar to a substance found in the jellyfish bell.

Jellyfish use their bells as a recognition system, so that when the creature comes into contact with the substance, it thinks it’s found itself instead of some tempting human flesh. Finally, the cream is believed to disrupt the jellyfish’s communication system so that it doesn’t get the signal to release its venom, she said.

Dr. Paul Auerbach former chief of emergency medicine at Stanford and one of the researchers, said he initially tried the cream about five years ago by smearing some on half of his neck and then jumping into the Mexican ocean awash in thimble jellyfish.

“The side I painted had two little red bumps on it, and the side I didn’t paint looked like a road map of Florida. That’s what convinced me we should do the studies,” said Auerbach, now a member of the adjunct clinical faculty. Auerbach became a consultant to Nidaria.

While Nidaria’s Porat admits that SafeSea has only been tested on a few of the more than 100 species of jellyfish known to be toxic to humans, he believes the lotion should be useful against all types.

“All jellyfish has the same stinging mechanism,” said Porat. “To the best of our knowledge, SafeSea is effective against all jellyfish. It hasn’t been tested on all varieties, but on a wide enough variety to be quite confident.”

Still Porat suggests using common sense and says that SafeSea should not be considered a “recommendation to swim in waters infested with jellyfish.” Nidaria recommends applying the lotion to all exposed flesh every 45 to 60 minutes in calm water and every 30 to 45 minutes in surf.

That’s bad news for jellyfish, and good news for ocean swimmers.

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