Irukandji Jellyfish

Irukandji Jellyfish

Simra Shahid

Irukandji jellyfish are one of several of the most poisonous jellyfish in the world, with an adult size of 1 cm long. They are the smallest and are considered to be one of the most hazardous. They are most commonly found in the southern waters of Australia, and rarely seen bordering the US.


There are 16 known species of the jellyfish. The Carukia barnesi, Malo kingi, Malo maxima, and the Malo filipina are the best known and were identified in 1964, which were the cause of irukandji syndrome. Irukandji syndrome had an unknown source until a scientist allowed the jellyfish to sting him, his son, and a lifeguard and in a short period of time they became ill, but survived confirming the cause of the syndrome. 


Irukandji syndrome symptoms consisted of headaches, nausea, restlessness, sweating, vomiting, increased heart rate and blood pressure, kidney pain, and burning sensation of skin. In rare instances the disease can result in cardiac arrest and death, but commonly cause fatal brain hemorrhages. Some species are thought to have caused envenomations in Australia. 


Irukandji jellyfish are slightly different from regular jellyfish. They have stingers on both their tentacles and on its bell, and the anatomy is thought to help it catch prey. They have the ability to fire stingers from the tips of their tentacles to inject the venom. The stings are described to be “100 times as potent as that of a cobra and 1,000 times stronger than a tarantula’s”. 


Between 1 January and early December 2020, 23 stings, seven of which required admission to health centers for Irukandji syndrome, have been sustained in the waters round Palm Island, off northern Queensland.