Irukandji Jellyfish

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Irukandji jellyfish (eer-uh-CON-jee) are small and extremely venomous jellyfish that are found mostly near Australia, and which cause symptoms collectively known as Irukandji syndrome. There are two known species, Carukia barnesi and the recently discovered Malo kingi.

The symptoms of Irukandji syndrome were first documented by Hugo Flecker[1] in 1952 and named after the Irukandji people whose country stretches along the coastal strip north of Cairns, Queensland.[2] The first-known of these jellyfish, Carukia barnesi, was identified in 1964 by Dr. Jack Barnes; in order to prove it was the cause of Irukandji syndrome, he captured the tiny jelly and stung himself, his son, and a life guard.

Like some other jellyfishes, the Irukandji have stingers (nematocysts) not only on their tentacles (on which the stingers are arranged in clusters that look similar to drops of water), but also on the bell. In addition, the venom is injected only from the tip of the stinger (nematocyst) rather than the entire length. This is why the initial sting is mild and there is a delayed reaction as the venom exerts its effects.

Very little is known about the life cycle and venom of Irukandji jellyfish. This is partly because they are small, inconspicuous, and fragile - so fragile that they cannot be kept in a normal fish bowl or aquarium because, if they hit the side, the impact will kill them.[3] Researchers conjecture that its venom possesses such potency to enable it to quickly stun its prey, which consists of small and fast fish. Judging from statistics, it is believed that the Irukandji syndrome may be produced by several species of jellyfish, but only Carukia barnesi and Malo kingi have so far been proven to cause the syndrome.[4]

[edit] Irukandji syndrome

Irukandji syndrome is produced by a very small amount of venom and includes severe pains at various parts of the body (typically excruciating muscle cramps in the arms and legs, severe pain in the back and kidneys, and a burning sensation of the skin and face), headaches, nausea, restlessness, sweating, vomiting, high heart rate and blood pressure. Magnesium sulphate is used as of 2007 to treat Irukandji syndrome. The sting itself is only moderately irritating; the severe syndrome is delayed for 5–120 minutes (30 minutes on average). The symptoms may last from hours to several days, and victims usually require hospitalization. The application of vinegar to the stung site can deactivate any remaining nematocysts on the skin. There is no known antidote for venom that has already entered the body. Morphine will not help reduce the pain[citation needed].

Scale drawing of Irukandji jellyfish and tentacles

When properly treated, a single sting is normally not fatal, but two people in Australia are believed to have died from Irukandji stings in 2002,[5][6] greatly increasing public awareness of Irukandji syndrome. It is unknown how many other deaths from Irukandji syndrome have been wrongly attributed to other causes. It is also unknown which jellyfish species can cause Irukandji syndrome apart from Carukia barnesi and Malo kingi.[7]

[edit] References

  1. ^ Pearn JH (1990). Australian Dictionary of Biography, Volume 14. Melbourne University Press. pp. 182–4. ISBN 0-522-84717-X. 
  2. ^ Flecker, Hugo (1952-07-19). "Irukandji sting to North Queensland bathers without production of weals but with severe general symptoms". The Medical journal of Australia 2 (3): 89-91. ISSN 0025729. PMID 14956317. 
  3. ^
  4. ^ Barnes, J H (1964-06-13). "Cause And Effect In Irukandji Stingings". The Medical journal of Australia 1: 897-904. ISSN 0025729. PMID 14172390. 
  5. ^ Fenner, Peter J; John C Hadok (2002-10-07). "Fatal envenomation by jellyfish causing Irukandji syndrome". The Medical journal of Australia 177 (7): 362-3. ISSN 0025729. PMID 12358578. 
  6. ^
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