Should We Stop Using Vinegar To Treat Box Jelly Stings? Not Yet—Venom Experts Weigh In On Recent Study

The dreaded Chironex fleckeri, responsible for some of the worst stings in the world. Does new research change everything we thought we knew about how to treat stings? Experts don't think so. Photo by Dr. Robert Hartwick When you're stung by a box jellyfish, you know it almost immediately. These somewhat squarish shaped cnidarians are armed to the bell with some of the most painful venom in the world. Long tentacles are packed with millions of stinging cells, called nematocysts, each with its own microscopic, needle-like harpoon-tipped tubule waiting to plunge into your flesh and inject the animal's intense venom. The pain is not only debilitating, it can also be deadly. More than 60 deaths from box jelly stings have been reported in the last forty years. Being stung is an awful experience. The best course of action is to remove any tentacles quickly to ensure that nematocysts that haven't fired don't get the chance to add their venom to the sting, and then treat for pain. Luckily enough, scientists discovered early on that vinegar (~5% acetic acid solution) irreversibly prevents nematocysts from firing, allowing people to rinse off tentacles without causing more trauma (which is also how the folk remedy of peeing on a sting originated, though vinegar is more effective and far less gross). For this reason, vinegar has been the go-to emergency response to box jelly stings for more than twenty years. It is currently the primary recommended treatment by the Australian Resuscitation Council, the American Heart Association and the American Red Cross. “Now (we’re saying) don’t do what we’ve been telling you to do for the last 30 years," Jamie Seymour, associate professor at James Cook University, told reporters at The Australian. Seymour's sudden change of heart is the result of new research published by him with colleagues from the Cairns Hospital, including lead author Philippa Welfare. Other news sites have been quick to cover the story which originated in a press release from James Cook University, warning that "vinegar on jellyfish sting can be deadly" and that "Queensland researchers have discovered the cure can kill." Not so fast, guys. The team used an in vitro model of stinging—a membrane attached inside a sterile cylinder—to discharge and collect venom from box jelly tentacles. The tentacles were placed on the rinsed membrane and electrically shocked with a six volt DC battery to stimulate discharge. The resultant 'venom' was then collected from the underside of the membrane using saline washes. Then the tentacles were treated with acetic acid (vinegar), and the underside washed again to determine what, if any venom was discharged during vinegar treatment. All the washes were evaporated and tested for venom activity against human heart cells. The results were unexpected: while the vinegar did prevent undischarged nematocysts from firing, it appeared to make those that had fired excrete even more venom. The scientists reported that vinegar caused a ~70% (+/- 32%) increase in venom discharge. "What we found was that by using vinegar, what you're effectively doing is increasing the venom load in the victim,” Seymour explained. These findings were supported, the authors say, by a survey of sting patients which found that those who received vinegar treatment required more pain medication. In addition to making stings worse, Seymour said that vinegar treatment distracts emergency responders from the most important part of sting treatment—monitoring vitals and ensuring the victim doesn't stop breathing. This new study, published in the brand-new journal Diving and Hyperbaric Medicine, has instantly garnered a lot of attention in Australia, with many calling for an immediate change of protocol. "I've been getting a steady stream of requests today from big organizations looking to change their policies in a hurry in response to today's media," said Lisa Gershwin, Director of the Australian Marine Stinger Advisory Services. But she and other scientists aren't convinced that the new findings are enough to call for a complete 180. Angel Yanagihara, jellyfish venom expert and research professor at the University of Hawaii, was immediately skeptical of the study. "I find the paper questionable on many levels, from the methodology to the conclusions." Yanagihara's first issue with the study is the membrane model using electric shock to stimulate venom discharge. "The extrapolation of this modest increase in recovery from an amniotic membrane model to live complex skin is not obvious," she said. Gershwin echoed her concerns. "Electrocuted tentacles in a lab environment don't have a parallel in the real world," she explained. "They offer no evidence, nor is there any from anywhere else, that this [model] bears any relationship to an actual sting event. Specifically, it seems reasonably likely (though unconfirmed) that the electrocution itself causes incomplete discharge, resulting in more venom to be discharged later. If this is the case, then the research is scientifically interesting but not applicable to the real world." Yanagihara also points out that the venom obtained is relatively weak compared to other research on box jellies. Her lab and others have isolated venom that over a thousand times more potent. "The fact that the activity of the recovered venom cytolytic activity is on the order of 10 mg/ml suggests that this is a very poor preparation." But moreover, Yanagihara is concerned that the results are not as cut and dry as they appear. There was no control solution applied to compare with vinegar after the electrical stimulation, thus it's unclear if using anything else would be better to remove tentacles. But more importantly, she says, the research didn't wholly ensure that the additional venom extracted by vinegar came from the tentacles' nematocysts, rather than venom stuck in or on the membrane after the initial sting. Vinegar could be causing changes to the membrane that release venom trapped within it, says Yanagihara, or is simply better than saline at bringing venom into solution and thus recovers more venom from the membrane surface than the saline wash. These alternative explanations were not accounted for because the researchers didn't test both sides of the membrane or use a control, says Yanagihara, and the difference is not inconsequential. Instead of being worse than we thought, vinegar could be an even better treatment than we realized. "In vivo vinegar could potentially assist in the extraction of venom from the upper layers of skin." But perhaps the greatest concern these scientists have is with the way the study is being represented in the media. "The paper clearly acknowledges and confirms that vinegar inhibits discharge of undischarged nematocysts," says Gershwin. "This subtle but utterly important distinction was lost in the media flurry." Yanagihara said it is "critical that the public understand" that in the paper, the authors state: