Two men were fishing 12 miles off the coast of Australia earlier this month when they were stung by a rare, dime-sized Irukandji jellyfish — one of the most venomous sea creatures in the world. As a sting from the nearly invisible jellyfish can cause Irukandji syndrome symptoms, including headaches, nausea, severe pain, muscle cramps, and cardiac complications that can lead to death, the fishers were immediately airlifted from their boat and rushed to an emergency room.
The two unnamed men were on a boat around 12 miles (19 kilometers) off the coast of Dundee Beach in Australia's Northern Territory when they were stung by an Irukandji jellyfish on Oct. 10, Australian news site 7News reported. …
It is unclear which species stung the two fishers, but most cases of Irukandji syndrome are caused by Carukia barnesi, according to the National Center for Biotechnology Information (NCBI). The species is only around 0.8 inch (2 centimeters) long …
Irukandji venom works in a similar way to tetrodotoxin, one of the world's most potent venoms that is administered by animals such as pufferfish and blue-ringed octopuses, according to NCBI. Both toxins stop nerves from properly signaling to muscles by blocking sodium ion channels.
…Although most people make a full recovery, there are cases of people continuing to experience pain up to a year later. Symptoms can begin as soon as five minutes after being stung, according to the Queensland Ambulance Service (QAS).
Like with tetrodotoxin, there is no known antivenom for Irukandji venom, and treatment is only supportive, according to NCBI. Experts recommend immediately dousing the sting area with vinegar because its acidic properties can prevent the barbs from releasing their venom, according to QAS.
Fortunately, both men were released from the hospital after 48 hours and were expected to fully recover. Australia sees between 50–100 cases of Irukandji syndrome every year, according to LiveScience.