What should you do if you’re stung by a box jellyfish? It may not be what you think

A sting by this Australian box jelly can lead to death in as little as 5 min. (Credit: A Yanagihara)

You’ve heard all the “cures” for jellyfish stings, from meat tenderizer to rubbing sand on it.

But do any of them actually work?

University of Hawaii professor Angel Yanagihara and John A. Burns School of Medicine postdoctoral fellow Christie Wilcox studied commonly recommended remedies to jellyfish stings from two box jellyfish species, the Hawaiian box jelly (Alatina alata) and the Australian box jelly (Chironex fleckeri).

The researchers say box jellies are among the deadliest animals in the oceans, responsible for more deaths every year than sharks.

“Anyone who Googles ‘how to treat a jellyfish sting’ will encounter authoritative web articles claiming the best thing to do is rinse the area with seawater, scrape away any remaining tentacles, and then treat the sting with ice,” said Yanagihara in a press release.

Not only did they find out some didn’t work, research showed some actions actually worsened stings.

The team found that some of the most commonly recommended actions, including rinsing with seawater and applying ice, dramatically increased the severity of the stings. Scraping the tentacles also significantly increased the venom injected by the stinging cells, the study said.

…it was clear that seawater allowed tentacle pieces, shed cnidae, and intact still fully active cnidae to be moved away from the initial site of contact, thus creating an opportunity for stinging beyond the original tentacle skin contact zone…

Stings where tentacles were scraped off and then treated with ice for 20 min had hemolytic zones more than 6.5 times as large as stings where tentacles were pulled off and not treated with any temperature treatment.

Even when the tentacles have been taken off the skin, microscopic stinging cells are still left behind and the pain can last for hours.

And if you thought urine would be good for the sting, don’t try it. Researchers say it doesn’t make it better.

So what should you do if you get stung in Hawaii?

The research showed slightly differing results for the two species tested, but overall, you should douse the tentacles with vinegar to prevent increasing the venom release. If no vinegar is available, then tentacles can be removed by careful plucking (not scraping).

After that, apply heat or immerse the area in hot water (45 °C) for 45 minutes to address the venom that’s already in the tissue. Heat markedly reduced hemolysis — or ruptured red blood cells — for both species, the study said.

If you’re in need of either, head to the nearest lifeguard station.

“Lifeguards are trained to treat jellyfish stings. They have hot packs and vinegar in their towers,” said Shayne Enright, spokeswoman, city Division of Ocean Safety and Lifeguard Services.

Research also pointed to venom-inhibiting technology, such as Sting No More, a product developed by Yanagihara with Hawaii Community Foundation, National Institutes of Health, and Department of Defense. It’s available online and in local ABC Stores.

The researchers note that all testing of Sting No More in the study was performed under an approved University of Hawaii Conflict of Interest plan.

The Waikiki Aquarium’s website includes a box jellyfish calendar as the influx happens between eight to 12 days after a full moon. The current influx period of box jellyfish is March 17 – 21.

Warning signs are posted on high-influx days and lifeguards patrol the beaches warning visitors.

“After that, it’s up to the beachgoer whether or not they’re going to go into the water,” Enright said.


Cubozoan Sting-Site Seawater Rinse, Scraping, and Ice Can Increase Venom Load: Upending Current First Aid Recommendations
Angel Anne Yanagihara and Christie L. Wilcox

Abstract: Cnidarian envenomations are the leading cause of severe and lethal human sting injuries from marine life. The total amount of venom discharged into sting-site tissues, sometimes referred to as “venom load”, has been previously shown to correlate with tentacle contact length and sequelae severity. Since <1% of cnidae discharge upon initial tentacle contact, effective and safe removal of adherent tentacles is of paramount importance in the management of life-threatening cubozoan stings. We evaluated whether common rinse solutions or scraping increased venom load as measured in a direct functional assay of venom activity (hemolysis). Scraping significantly increased hemolysis by increasing cnidae discharge. For Alatina alata, increases did not occur if the tentacles were first doused with vinegar or if heat was applied. However, in Chironex fleckeri, vinegar dousing and heat treatment were less effective, and the best outcomes occurred with the use of venom-inhibiting technologies (Sting No More® products). Seawater rinsing, considered a “no-harm” alternative, significantly increased venom load. The application of ice severely exacerbated A. alata stings, but had a less pronounced effect on C. fleckeri stings, while heat application markedly reduced hemolysis for both species. Our results do not support scraping or seawater rinsing to remove adherent tentacles.

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