Marine stingers in far north Queensland

Aquatic sports dematoses. Part 2 - in the water: saltwater dermatoses

The second part of this three-part series on water-related dermatoses will discuss dermatologic conditions seen in athletes exposed to saltwater. The vast majority of the following dermatoses result from contact with organisms that inhabit saltwater, including bacteria, cnidarians, and echinoderms. This review also will include other dermatoses affecting saltwater athletes and should serve as a guide for dermatologists, sports medicine physicians, and other medical practitioners in recognition and treatment of these dermatoses.

Warmer waters in the Northern Territory--herald an earlier onset to the annual Chironex fleckeri Stinger season

The discovery that Chironex fleckeri occurs annually in northern Australia occurred long ago, possibly before written records were available by local indigenous people, however, to date the precision of this yearly phenomenon is still not fully understood. Sea surface temperature (SST) appears to be a determining factor signaling the "arrival" of C. fleckeri each year. Anthropogenic climate change modeling predicts global rises in SST. Rises in SST may result in an earlier "arrival" of C. fleckeri during the dry season, possibly necessitating extension of the official Northern Territory stinger season to commence in September (currently October through to June). This short report presents data to support this hypothesis, facilitating policy makers with an environmental cue upon which changes to current stinger season can be based--prior to painful and potentially life-threatening presentations.

The in vivo cardiovascular effects of the Irukandji jellyfish (Carukia barnesi) nematocyst venom and a tentacle extract in rats

Envenoming by Carukia barnesi may produce life-threatening Irukandji syndrome. There is little published on the activity of C. barnesi venom. This is the first study to investigate the in vivo cardiovascular effects of C. barnesi venom and a tentacle extract (devoid of nematocysts). Venom (50 microg/kg or 100 microg/kg, i.v.) produced a pressor response (42+/-3 and 44+/-6 mmHg, respectively; n=4) and increase in heart rate (31+/-5 and 13+/-2 bpm, respectively; n = 4) in anaesthetised rats. These changes were not dose-dependent and were followed by cardiovascular collapse in one of four rats receiving 50 microg/kg and three of four animals receiving 100 microg/kg. Prazosin (50 microg/kg, i.v.) significantly attenuated the venom (50 microg/kg, i.v.)-induced pressor response (-8+/-3 mmHg; P < 0.05; n = 4) and tachycardia (-9+/-4 bpm; P < 0.05; n = 4). Tentacle extract (100 microg/kg; i.v.) produced a pressor response (51+/-12 mmHg; n = 3) and an increase in heart rate (35+/-1 bpm; n = 3) in anaesthetised rats, with no subsequent cardiovascular collapse. The results of this study are consistent with the effects shown by humans envenomed by C. barnesi which are postulated to be a result of catecholamine release. We show, for the first time, that C. barnesi tentacle extract, free of nematocyst material, produces cardiovascular effects which are distinct from those caused by venom derived from isolated nematocysts.

Cnidarian (coelenterate) envenomations in Hawai'i improve following heat application

A retrospective review of medical records from 113 patients with cnidarian stings in western O'ahu, Hawai'i, was conducted for the 5-year period 1994-98. The most common clinical feature was acute local pain, but cases of anaphylaxis or anaphylactoid syndrome and a persistent or delayed local cutaneous syndrome were also documented. Six cases resembled the Irukandji syndrome described from northern Australia, characterized by severe pain and signs of catecholamine excess, including muscle cramping, elevated blood pressure, diaphoresis, and tremor. Treatment with heat application, usually by means of a whole-body hot shower, appeared to provide better clinical improvement than parenteral analgesics or tranquillizers, particularly in patients with the Irukandji-like syndrome. The heat sensitivity of one or more of the Carybdea alata venom components might account for the effect of heat treatment. Prospective, randomized, controlled clinical trials should be performed to assess heat treatment for cnidarian envenomation.

Prospective study of jellyfish stings from tropical Australia, including the major box jellyfish Chironex fleckeri

OBJECTIVE

To determine the immediate and delayed effects of jellyfish stings, and correlate these with microscopic identification of jellyfish nematocysts.

DESIGN

Prospective study of patients presenting with jellyfish stings.

PARTICIPANTS AND SETTING

40 people presenting with jellyfish stings to the emergency department of a teaching hospital in tropical Australia between 1 August 1999 and 31 July 2000.

MAIN OUTCOME MEASURES

Clinical diagnosis (sting by Chironex fleckeri, "Darwin carybdeid" or other jellyfish, or "Irukandji" syndrome); clinical severity; delayed hypersensitivity; and sticky-tape sampling and microscopic identification of nematocysts.

RESULTS

Patients were aged 2-50 years, with eight aged under 15 years; 23 were male. Presentations were consistent with C. fleckeri sting in 28 cases, Darwin carybdeid sting in five, and Irukandji syndrome in four. Sticky-tape sampling was done in 39 patients and was positive for C. fleckeri nematocysts in 23 and for non-C. fleckeri nematocysts in six, with nematocysts not detected in 10 (including all four with Irukandji syndrome). All microscopically confirmed C. fleckeri stings had typical clinical presentations. None of the stings were life-threatening, and no antivenom was given. Delayed hypersensitivity reactions were seen in 11 of the 19 patients (58%) followed up after stings positive for C. fleckeri nematocysts.

CONCLUSIONS

Although most jellyfish stings presenting to Royal Darwin Hospital I were caused by C. fleckeri, severe envenomation was rare. There was a strong association between clinical features and sticky-tape identification of nematocysts. Delayed hypersensitivity was common after C. fleckeri stings.

A year's experience of Irukandji envenomation in far north Queensland

Envenomation by the Irukandji jellyfish (Carukia barnesi) can result in an array of systemic symptoms known as Irukandji syndrome. In 1996, 62 people presented to Cairns emergency departments with Irukandji envenomation: 57 developed systemic symptoms, and 38 required parenteral narcotics. All patients were discharged home within 24.5 hours, except for two who required high-dependence care for pulmonary oedema. Patients were more likely to be stung on hotter days, with lower-than-average rainfall in the past seven days, and with winds from the north, but less-than-average wind speed. We offer a protocol for treating patients with Irukandji envenomation.