Box jellyfish, sea wasp

A large but almost transparent jellyfish with a box-shaped bell up to 38cm in diameter. Up to 17 ribbon-like tentacles arise from each of the four corners. These may contract to about 10cm or may extend up to 3m.

Shallow, tropical Australian waters north of Agnes Water, Queensland, all Northern Territory waters and Western Australia south to Exmouth. Stings from Chironex have been recorded predominantly in coastal areas.

Its sting causes immediate severe burning pain and whip-like marks, often with tentacles remaining on the stung area. Severe stings may cause the casualty to stop breathing and suffer cardiac arrest.

1. Remove casualty from water if safe to do so
2. DRSABCD
3. If casualty has more than one localised single sting or looks/feels unwell, dial triple zero (000) and seek assistance from a lifeguard if available
4. Assess casualty and commence CPR immediately if required
5. If possible, treat the sting by pouring vinegar for at least 30 seconds and then pick off the tentacles
6. If vinegar is not available, pick off tentacles (this is not harmful to the rescuer) and rinse well with sea water. Apply a cold pack or ice in a bag for analgesia

• Anti venom is available for Chironex fleckeri and other multi-tentacled box jellyfish stings at hospitals and ambulance stations in tropical coastal areas
• Casualties who initially appear stable but experience severe symptoms in the following 30 minutes may be suffering Irukandji syndrome and need urgent medical care

• Chironex fleckeri is widely regarded as the world’s most venomous animal
• There have been recorded fatalities due to box jellyfish stings in Australian waters. A box jellyfish can kill an adult human in 2-3 minutes with only 2-3m of tentacles
• Chironex fleckeri become deadly when the bell reaches 8-10cm in size, however all sizes can still inflict significant painful stings