Beware of the Irukandji Jellyfish
Increase in stings in Australia

June 3, 2002

The tropical Northeast coast of Australia is one of the most beautiful areas in the world. However, lurking near the surface of these blue waters is a small but dangerous creature: the Irukandji jellyfish (Carukia barnesi). The Reuters News Agency reported that 200 people have been hospitalized and two people have died this season after being stung by Irukandji jellyfish. Usually only 30 people are sent to the hospital each year for these stings.

The Irukandji jellyfish has a bell that is only 2-2.5 cm across. The stinging apparatus, called a nematocyst, is located in the tentacles and bell. The nematocyst is like a miniature poison dart or harpoon. Once triggered, nematocysts shoot out a small barbed tube that injects a toxin. The toxin triggers an increase in the levels of the neurotransmitters norepinephrine and epinephrine in the victim.

Symptoms of "Irukandji syndrome" include:

  • Pain around the site of the sting
  • Muscle cramps
  • Sweating
  • Nausea/vomiting
  • Headache
  • High blood pressure (hypertension); increase in heart rate
  • Fluid in the lungs (pulmonary edema)

No one knows what has caused the unusual increase in the number of Irukandji jellyfish stings and at this time, there is no antivenom for the toxin.

Did you know?

  • In 1952, H. Flecker named Irukandji syndrome after an Australian aboriginal tribe.

  • The scientific name of the Irukandji jellyfish is Carukia barnesi. It is named after J.H. Barnes who associated this animal with Irukandji syndrome in 1964. Barnes caught some of the jellyfish and tested the sting on himself and his son. Both Barnes and his son ended up in the hospital with Irukandji syndrome!

References and further information:

  1. A year's experience of Irukandji envenomation in far north Queensland - Medical Journal of Australia, 169:638-641, 1998.
  2. "Irukandji" syndrome: a risk for divers in tropical waters - Medical Journal of Australia, 167:649, 1997.
  3. DANGERS ON THE REEF...Irukandji
  4. Fenner, P.J. and Harrison, S.L. Irukandji and Chironex fleckeri jellyfish envenomation in tropical Australia. Wilderness and Environmental Medicine, 11:233-240, 2000.

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