Box jellyfish

The Box jellyfish (Chironex fleckeri) is found during the summer months in the coastal waters of northern Australia, from Gladstone in Queensland to Broome in Western Australia, but not on the Great Barrier Reef. It is the most dangerous jellyfish and indeed one of the most dangerous venomous creatures in the world. It is large, weighing up to 6 kg and measuring about 20-30 cm across the bell. The tentacles may stretch up to 2 metres. It is transparent in the water, and therefore difficult to see. It has 4 bundles of tentacles, which may number up to 60 in total. Each tentacle contains many millions of nematocysts or stinging cells which discharge venom through the skin on contact. Contact with a large amount of tentacular material over a wide surface area can result in massive envenomation. Most stings occur in the summer months in shallow water near the beach, and are particularly common in children. (In two case series the average age of box jellyfish sting victims was 14 years with a median age of 11 years.)

• Sea wasp

Symptoms and Signs of Box Jellyfish Envenomation
These can include:

• Severe localized pain, often associated with vigorous attempts by the patient to remove the tentacles (this may make the envenomation worse by causing the discharge of further nematocysts)
• Wide (0.5 -1cm) erythematous lines where the tentacles have been in contact with the skin. These may cover a large area, an indication of severe envenomation.
• Confusion, agitation, unconsciousness, collapse with respiratory failure and/or cardiac arrest

Death can occur within 5 minutes following massive envenomation. The mechanism of toxicity are poorly understood, but death is thought to be due to respiratory failure, possibly central in origin, or to direct cardiotoxicity leading to A-V conduction disturbances or to paralysis of the cardiac muscle in systole. Patients may become unconscious before they can leave the water. There have been at least 63 confirmed deaths from envenomation by Chironex fleckeri in the Indo-Pacific region. In addition to cardiotoxic and neurotoxic properties, the venom also contains dermatonecrotic components producing patches of full thickness skin necrosis (see gallary images for 'Jellyfish') that may result in severe and permanent scarring. There is also a haemolytic component in Chironex fleckeri venom, although it is of doubtful clinical significance.

Treatment of Box Jellyfish Envenomation
Due to the rapidity of onset of symptoms, immediate first aid is vital and cardiopulmonary resuscitation may be required. Remaining undischarged nematocysts should be inactivated with large quantities of dilute (3-5%) acetic acid (i.e. household vinegar) once the patient has been safely removed from the water. Antivenom may be administered by lifesaving or other paramedical personnel at the scene, via the intramuscular route, although intravenous administration is preferable if appropriately skilled personnel are available. The antivenom, which has been available since 1970, consists of purified sheep immunoglobulin and no adverse reactions have been reported following its use in over 100 cases. Its efficacy has been established experimentally by in vitro neutralization and subsequent protection of experimental animals.

Indications for Box Jellyfish Antivenom
Box Jellyfish antivenom is recommended for all but minor stings. Specific indications include:

• cardiorespiratory arrest, or cardiac arrythmias
• difficulty with breathing, speech or swallowing
• severe pain
• extensive skin lesions.

In hospital, intravenous antivenom should be administered promptly if it has not already been given or if the patient remains symptomatic. Assisted ventilation and narcotic analgesia may be required. Early administration of antivenom may result in reduced pain and decreased scarring secondary to dermatonecrosis.

Precautions to Avoid Envenomation
To minimise the risk of a potentially fatal box jellyfish sting in Australian beaches:

• Avoid swimming in areas where box jellyfish are found during the jellyfish season (variable, but approximately September to March) and heed warning signs on beaches. N.B. avoid swimming alone or at remote beaches.
• Wear specially designed "stinger suits" while in known box jellyfish waters
• Swim at beaches patrolled by life savers, preferably equipped with vinegar, antivenom and basic resuscitation facilities
• Exercise caution on entering the water (do not dive or run into the water)
• Strictly supervise children, who are more prone to stings, and whose lesser body weight may render them more susceptible to the effects of the venom
• Swim at beaches that have been netted to exclude box jellyfish

Related Treatments

• Jellyfish, Treatment for stings
• Jellyfish, Treatment for stings

Books

• Stackhouse, J., Australia's Venomous Wildlife, Paul Hamlyn, Sydney, 1970, 144 pp. [ Details... ]

Conference Papers

• Hansen, T. J., 'Sea-Wasp Syndrome or Acute Nematocyst Poisoning', in International Convention on Life Saving Techniques, Sydney, March 11 th-20th, 1960, The Committee of the 1960 International Convention on Life Saving Techniques, 1963, pp. 66-71. [ Details... ]
• Lockwood, L., 'Fatal Case of Sting by Box Jelly-Fish', in International Convention on Life Saving Techniques, Sydney, March 11 th-20th, 1960, The Committee of the 1960 International Convention on Life Saving Techniques, 1963, pp. 110-111. [ Details... ]
• Southcott, R. V., 'Fatal and Other Stingings by Sea-Wasps', in International Convention on Life Saving Techniques, Sydney, March 11 th-20th, 1960, The Committee of the 1960 International Convention on Life Saving Techniques, 1963, pp. 72-73. [ Details... ]

Journal Articles

• Berger, E. W., 'Physiology and Histology of the Cubomedusae, Including Dr. F. S. Conant's Notes on the Physiology', Mem. Biol. Lab. Johns Hopkins. Univ., vol. 4, no. 4, 1900, pp. 1-84. [ Details... ]
• Conant, F. S., 'The Cubomedusae. A Dissertation Presented for the Degree of Doctor of Philosophy, in the Johns Hopkins University, 1897', Mem. Biol. Lab. Johns Hopkins. Univ., vol. 4, no. 1, 1898, pp. 1-61. [ Details... ]
• Hartwick, R., Callanan, V. and Williamson, J., 'Disarming the Box-Jellyfish. Nematocyst Inhibition in Chironex Fleckeri', The Medical Journal of Australia, vol. 1, 1980, pp. 15-20. [ Details... ]
• Pope, E. C., 'Venomous Jelly-Fish - The Sea Wasps', Walkabout, vol. 23, no. 12, 1957, pp. 40-41. [ Details... ]
• Southcott, R. V. and Kingston, C. W., 'Lethal Jellyfish Stings: A Study in Sea Wasps', The Medical Journal of Australia, vol. 1, 1959, pp. 443-444. [ Details... ]