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Jellyfish responsible for Irukandji syndrome

M. Little, P. Pereira, T. Carrette, J. Seymour
DOI: http://dx.doi.org/10.1093/qjmed/hcl057 425-427 First published online: 10 May 2006


Irukandji syndrome is a distressing array of symptoms following a jellyfish sting.1 Generally, symptoms develop 20–60 min after the sting, and include back pain, nausea, abdominal cramps, sweating, hypertension, tachycardia and a feeling of impending doom.1–3 The sting usually leaves only mild local signs. In a series of 116 cases presenting to Cairns Base Hospital in one year, 64% required hospital admission and there was one death.2 Patients suffer severe pain, as demonstrated by the adult patients in this series requiring a mean dose equivalent to 42 mg of morphine.2 There have been case reports of patients developing life-threatening cardiac failure requiring intubation and inotropic support.3 In Huynh's series, 22% had evidence of myocardial injury, with an elevated troponin.2 Reports of Irukandji syndrome have come from Australia, Hawaii, Florida, French West Indies, Bon Air, Caribbean, Timor Leste and Papua New Guinea.1 The syndrome may well occur in many other parts of the world, but not be recognized.

Only two jellyfish have previously been definitively shown to cause Irukandji syndrome.1,,4 In 1961, Barnes captured two small jellyfish (later named Carukai barnesi in his honour) in Palm Cove, Australia, and demonstrated this to be the casual agent by stinging the local lifeguard, his 9-year-old son and himself. All three developed Irukandji syndrome.1 Despite reports of Irukandji syndrome from many locations only one other, as yet unnamed, jellyfish has been identified as causing Irukandji syndrome.4 Very little is known about the venom or ecology of these jellyfish.

We now report five further cases of identified cubozoan jellyfish that we believe can cause Irukandji syndrome (Table 1), namely Alatina nr mordens, Carybdea alata, Malo maxima, Carybdea xaymacana and an as-yet unnamed ‘fire jelly’.

View this table:
Table 1

Details of envenomings

Date, patient detailsLocationHow jellyfish locatedSymptomsPatient outcomeIdentified jellyfishComment
Oct 2002, 34M and 22 FOsprey Reef, near Cairns, AustraliaCollected by envenomed patients when stungLocal pain, nausea and abdominal crampsSymptoms settled within 12 hAlatina nr mordens, bell height 100 mm, tentacles 1000 mmHas 6 eyes, (not 2 or 4) and jellybean-shaped statoliths, suggesting these are not A. mordens6
Apr 2001, 28MRoebuck Bay, Western AustraliaCollected by envenomed patient when stungBack and abdominal pain, nauseaSymptoms settled within 6 hMalo maxima, bell height 50 mm
Oct 2000, 37M and 24F3 nautical miles offshore from Waikiki Beach, Hawaii, USACollected by envenomed patients when stungAbdominal, knee and ankle pain, nausea and sweatingSymptoms settled in 2 hCarybdea alata, bell height 70 mm
Apr 2000, 19FBriggs Reef nr Cairns, AustraliaCaptured at time of sting by dive buddyBack and body pain, sweating, nausea, hypertensionHospital admission for 2.5 days. Developed abnormal ECG and elevated troponin (5.4 mcg/l, N < 0.7). RecoveredNot formally named, colloquially called ‘fire jellies’. Bell height 100 mmDistinctive pink/purple nematocysts on bell, 4 strap like tentacles 50 mm length when contracted
Dec 1997, 5 children aged 4–10Inside Palm Cove nets, Cairns, Australia60 + jellyfish captured at time of stings at the north and south edge of an enclosed netted swimming areaBack pain, nausea sweating hypertensionOvernight admission, opiate analgesia. RecoveredCarybdea xaymacana, bell height 40 mm

Accurate identification of creatures responsible for human envenoming is essential. In Australia, the white-tailed spider, Lampona sp, was incorrectly identified as being responsible for necrosing ulcers. This led to much anxiety, misdiagnosis and incorrect treatment of patients, until a prospectively designed study demonstrated that this spider's bite caused only minimal local symptoms.5 There have been very few data on jellyfish stings that correlated clinical syndromes with accurate identification of the offending jellyfish; published studies have often assumed that if a cubozoan jellyfish is found in a region, it is responsible for the envenoming syndrome,6 but with little data to support such assumptions. If research is to be performed on both the ecology and venom of the animal, it is essential the correct creature is identified.

We know little about the lifecycle of these jellyfish, and currently there is no antivenom. We hope that the recognition that Irukandji syndrome is due to many jellyfish worldwide, will spur further research into identifying the ecology of the jellyfish and the venom components responsible, and hopefully produce an effective treatment.


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