The Irukandji jellyfish (Carukia barnesi) is one of the most venomous marine organisms on Earth.
Two Australian fishermen were recently airlifted to hospital by helicopter after being stung by one of the world's most venomous jellyfish while out in the open ocean.
Two unnamed men were on a boat about 12 miles (19 kilometers) off the coast of Dundee Beach in Australia's Northern Territory when they were stung by an Irukandji jellyfish on October 10, Australian news outlet 7News reported.
There are 16 known species of Irukandji jellyfish, all endemic to the deep seas around northern Australia. The venom of each of these tiny box jellyfish can cause Irukandji syndrome, an extremely painful and potentially fatal set of reactions.
It is not known which species stung the two fishermen, but most cases of Irukandji syndrome are associated with Carukia barnesi, according to the National Center for Biotechnology Information (NCBI). The species is only about 0.8 inches (2 centimeters) long, but is one of the most venomous sea creatures on the planet.
The men were taken to a medical facility from the boat and released 48 hours later. Both are expected to make a full recovery, 7News reports.
Another species of Irukandji jellyfish (Malo kingi) is placed in a small plastic tube.
According to the Australian Museum, C. barnesi delivers its toxins through specialized stinging cells known as nematocysts, which cover its four tentacles and project venomous spines at its prey or as a defense mechanism against predators. Because of their small size, most people are unaware of the presence of jellyfish until they are stung.
Irukandji venom works similarly to tetrodotoxin, one of the most potent poisons in the world, which is produced by animals like pufferfish and blue-ringed octopuses, according to the NCBI. Both toxins prevent nerves from properly transmitting signals to muscles by blocking sodium channels.
Symptoms of Irukandji syndrome include severe muscle pain, back discomfort, headaches, nausea, vomiting, anxiety, high blood pressure, breathing problems and cardiac arrest, according to the NCBI. While most people make a full recovery, there are cases of suffering lasting up to a year after the bite. Symptoms can appear as soon as five minutes after exposure, according to the Queensland Ambulance Service (QAS).
Sourse: www.livescience.com
