Master of Pain – Irukandji Jellyfish

Are you afraid of sharks? If you are, here’s an animal no larger than your thumbnail that you should fear far more. At least, if you plan on ever going swimming in Northern Australia’s waters.

The Irukandji jelly (Carukia barnesi) is named after the Irukandji people on the coast North of Cairns who have long been familiar with and feared it. It is a type of box jelly and possibly the most venomous creature on the planet. It has four small tentacles that can be extended up to a little over three feet if necessary. Each of these is coated in nematocysts, or stinging cells, that fire microscopic harpoons loaded with venom into anything they brush against. There are also stinging cells covering its bell, which is unusual for most jellyfish species. This is thought to be an adaptation to protect itself from prey that could rip it apart while trying to escape. One touch anywhere and the prey is instantly killed.
This venom isn’t as deadly to humans, but getting stung is still no laughing matter. The symptoms of a sting from Carukia barnesi have come to be known collectively as Irukandji Syndrome. The story of how this jelly was proven to cause the syndrome is slightly amusing, yet still horrible. A medical doctor in Australia by the name of Jack Barnes noticed one of these jellies swimming by so, in order to prove it was the culprit, deliberately caught it and proceeded to sting himself, his young son, and a nearby lifeguard. All of them were then afflicted with the syndrome, but they all survived. That brings us to the heart of Irukandji Syndrome. It is not often fatal, but it is described as causing possibly the most excruciating pain a person could ever experience.
When stung, there is little to no mark where the tentacles or bell made contact. It doesn’t even feel any more irritating than a mosquito bite at that point. Within half an hour, though, the venom starts taking its full effect and the symptoms grow more and more intense. These usually include muscle aches, severe headaches, chest and stomach pain, nausea, vomiting, tachycardia (rapid heart rate), profuse sweating, anxiety, and the unique symptom of “impending doom”. There have been records of victims being so sure they were going to die that they begged the doctors to just kill them to get it over with. The pain alone is also a reason to beg for death. Patients have described it as being so intense that they want to rip their skin off, and as coming in waves like labor pains (only about 100 times worse) but never completely receding. Even the highest doses of painkillers possible to safely administer have almost no effect in taking the edge off and the pain can last for a little over a day, sometimes taking up to two weeks to completely go away.
This is definitely not an animal to cross paths with. Even worse, there is currently no antivenom.

Amazing how something so small and fragile, even beautiful, can cause so much suffering isn’t it?

1. Ramasamy, Sharmaine, et al. “The in vivo cardiovascular effects of the Irukandji jellyfish (Carukia barnesi) nematocyst venom and a tentacle extract in rats.” Toxicology letters 155.1 (2005): 135-141.

2. Carrette, Teresa J., Avril H. Underwood, and Jamie E. Seymour. “Irukandji syndrome: a widely misunderstood and poorly researched tropical marine envenoming.” Diving and Hyperbaric Medicine 42 (2012): 214-223.

3. Lyons, Kelsey. “Carukia Barnesi.” Irukandji Syndrome: : Irukandji Jellyfish. University of Wisconsin La Crosse, 26 Apr. 2013. Web. 19 Apr. 2015. .

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