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Box jellyfish

in category: 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.)

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

cardiorespiratory arrest, or cardiac arrythmias

difficulty with breathing, speech or swallowing

severe pain

extensive skin lesions.

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

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:

In hospital, intravenous antivenom should be administered promptly if i t 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:

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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

Related

Jellyfish

Related

Jellyfish, Australian

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