Two women stand in front of the ocean, holding bottles of Safe Sea. Two women stand in front of the ocean, holding bottles of Safe Sea. Safe Sea used by two women who were able to swim the Catalina Channel due to its protection against jellyfish stings. (Photo courtesy Safe Sea)

Innovative sunblock doubles as jellyfish sting preventer

Israeli invention allows groups to swim for long distances without being stung.

Jellyfish hurt more people every year than sharks or killer whales, according to a recent BBC report. Jellyfish stings can range from uncomfortable to extremely painful, depending on what type of Cnidarian smacks you with its tentacles. While even the milder stings are enough to keep most casual swimmers out of the water when there's a jellyfish alert, the stings can become especially problematic for long-distance swimmers in deep water. 

But science is coming to the rescue. To safeguard against stings, serious swimmers, including The Night Train Swimmers, a group founded by San Francisco Bay Area open-water swimmers, are now using anti-jellyfish cream. A combination sun block, jellyfish block, these creams are rubbed over your skin, blocking solar rays from harming you, as well as jellyfish tentacles from stinging you. There are several on the market, including MedusylLifesystems Active, and Safe Sea.

Safe Sea, the first jellyfish-sting block, was developed by Dr. Amit Lotan, who said his basic motivation was to "keep ocean lovers in the water and out of agony." 

With his background in jellyfish cell biology and ecology, Lotan's Ph.D. research at the Hebrew University of Jerusalem and Tel Aviv University was partially funded by the United Nations because of the public health gains of reducing jellyfish stings worldwide. Lotan was the first scientist to understand how jellyfish poison is delivered into our skin, and his research was published in the journal Nature.

"Jellyfish contain millions of stinging cells that are analogous to high tech micro-injectors," Lotan told From The Grapevine. "Activation of stinging cells depends on several mechanical and chemical events. Our understanding of the morphology and biochemistry of the stinging organelles enabled us to identify the chemicals that inhibit the triggering pathway of the stinging cell and thereby to develop Safe Sea."

"Over 2000 stings can penetrate one square millimeter of human skin during contact with a jellyfish tentacle." Dr. Amit Lotan

He created Safe Sea to block these stinging cells in four different ways. First, it makes the skin too slippery for stinging tentacles to attach to the skin; the block also absorbs the human skin secretions that let the jellyfish know when it touches you that it's in contact with a prey or predator (which gets them stinging). Third, chemicals in Safe Sea block the pathways in the skin where the stinging process is activated. 

Lastly, the cream disarms its menacing tentacles: "A stinging cell is a dense 'capsule' containing a long folded needle. Pressure builds in this capsule just prior to stinging. As the pressure builds, the capsule is forced open and the needle shoots out like a harpoon, injecting its target with toxin at a force equivalent to a bullet being fired from a gun. This all happens in a fraction of a second; jellyfish stings are among the most rapid mechanical events in all of cellular biology. Safe Sea reduces the pressure in stinging cells so that they cannot fire - effectively disarming them," according to the  Safe Sea website. 

Lotan said, "Over 2,000 stings can penetrate one square millimeter (over a million per square inch) of human skin during contact with a jellyfish tentacle," which is why the sting is so painful and why the creams need to be spread over all exposed skin for protection.

Jellyfish stingsSafe Sea can help prevent jellyfish stings like these. (Photo: Thomas Quine/Flickr) 

Does anti-jellyfish cream really work? A test, in which 24 participants signed up for the unenviable task of putting their arms (one with protector, one without) into a tub of stinging jellyfish, showed that it did. “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's School of Medicine who directed the study. (Dr. Lotan was involved, but not the primary researcher in the study.) 

Consumers who've tried Safe Sea also report that it prevents strings from other creatures, including sea lice, the immature larvae of jellyfish and other ocean stingers. Sea lice have the same stinging cells as the larger animals, but they are less intense due to their size. 

But if you do get stung? Use vinegar to treat it, say the experts at Bass Pro Shops: "In the case that you get stung by a jellyfish, get out of the water immediately. If the jellyfish sting covers a large area of the body or you’re suffering from any symptoms typical of a severe reaction, seek medical attention immediately. If your sting is less severe, it’s suggested that you treat the area with vinegar and remove the tentacles from skin with a rigid object like a credit card."

These products address a real concern. Human-jellyfish encounters are on the rise due to more frequent jellyfish "blooms," likely due to global warming and overfishing (fish like to eat jellies). The blooms are most common in the north Atlantic and Mediterranean, due to those bodies of water both having higher oxygen concentration, but they can be found anywhere. 

Some scientists are keeping track of the rising jellyfish risk; the Jellyfish Data Initiative (JeDI) will be launched soon, and anyone will be able to use it to find out if there are reports of jellyfish in bodies of water near them. Dr Cathy Lucas, a marine biologist from the National Oceanography Centre in Southampton, told the Daily Mail: 'People will be able to contribute their own data... It will be like a jellyfish version of Google Maps."

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