The CDC Safety and Injury Unit provide safety promotion messages before the start of stinger season each year. The stinger season runs from October 1 to May 31 when box jellyfish are more prevalent in the water.
The major box jellyfish, Chironex fleckeri, has rapidly acting venom in its tentacles that is capable of killing a person in less than 5 minutes. C. fleckeri are almost invisible in the water with a bell up to 35 cm in diameter, and up to 60 tentacles each of which can reach 3 metres long. Covering each tentacle are millions of stinging cells (nematocysts) which inject their venom into the skin on contact. The person immediately feels excruciating pain and within minutes white welts appear where the tentacle contact occurs. These welts change to become red whip-like lines and subsequent skin death may lead to permanent scarring. A large dose of venom, particularly in small children, may cause rapid cardiorespiratory arrest and death within a few minutes.
Large numbers of C. fleckeri appear in Northern Australian waters between October and May each year, when the sea water becomes warmer. Although the majority of jellyfish stings have occurred in the stinger season of October to May, confirmed jellyfish stings have occurred in every month of the year. A large proportion of stings occur in shallow waters less than 1 metre deep and when victims are entering the water. Stings are least common on outgoing tides and more common on days with still conditions. Box jellyfish are often found in the shallows, in tidal creeks and around boat ramps.
Stings from several species of smaller jellyfish may produce Irukandji syndrome in the victim. The initial sting of these jellyfish is usually not very painful, although, this is not always the case. About 5-45 (usually 30) minutes after being stung, the person starts to develop 'Irukandji syndrome' - a set of symptoms that often include severe lower back pain, muscle cramps, vomiting, restlessness and anxiety. In rare cases, the victim can suffer pulmonary oedema (fluid on the lungs), hypertension or heart failure that could be fatal if not treated. Most cases of Irukandji syndrome occur between October to May but cases have been recorded in all months of the year.
Top End hospitals and health clinics report around 40 people presenting with jellyfish stings per year in the Northern Territory. The last reported death in the NT was in November 2007 when a 6 year old boy from a remote Aboriginal community died from confirmed C. fleckeri envenomation. Children are more at risk of life-threatening envenomation due to their smaller body mass in relation to the volume of venom injected.
Protection from jellyfish
The best way to avoid jellyfish stings is to avoid contact with sea water, particularly during the period 1 October and 31 May when they are more prevalent. People should be aware that stings are possible at any time of the year.
Young children are at greater risk and should not enter the water at all during the 'stinger season'. It is highly recommended that they wear protective clothing, such as stinger suits or long shorts and a long sleeved top, if they should enter the water at any time. Protective clothing is also recommended for older children and adults.
Treatment for jellyfish stings
Immediate first aid is vital and cardiopulmonary resuscitation may be needed.
- Remove the person from the water
- Call for help (dial 000)
- Assess the person and commence CPR as necessary
- Pour vinegar if available on the area of the sting to stop further discharge from the stinging cells - do not wash with fresh water
- If vinegar is unavailable, pick off any remnants of the tentacles (the skin of the pads of the fingers and palm is thicker so any stinging will usually be minor) and rinse sting well with salt water (not freshwater)
- Seek medical assistance and transport to hospital immediately
Ice may be applied for local pain relief for less severe stings.
Publications and resources regarding stinger safety
There have been several articles published in the NT Disease Control Bulletin regarding stingers and stinger safety. These include:
|Neilson M, Skov S,||2014||Beware of jellyfish causing Irukandji syndrome|
|Neilson M, Skov S.||2012|
The Safety and Injury Unit have developed several resources with Stinger Safety messages:
- Splash stinger safety fact sheet (Adobe PDF document - 1136KB)
- Splash stinger safety poster (Adobe PDF document - 1936KB)
- CDC box jellyfish fact sheet I RTF (860KB)
- Currie BJ. Clinical toxicology: A tropical Australian perspective. Therapeutic Drug Monitoring. 2000;22:73-78.
- Currie, B. and Jacups, S. Prospective study of chironex fleckeri and other box jellyfish stings in the "Top End" of Australia's Northern Territory. Medical Journal of Australia. 2005;183(11/12):631-636.
- Fenner PJ, Harrison SL. Irukandji and Chironex fleckeri jellyfish envenomation in tropical Australia. Wilderness Environmental Medicine. 2000;11(4):233-40.
- O'Reilly GM, Isbester GK, Lawrie PM, Treston GT, Currie BJ. Prospective study of jellyfish stings from tropical Australia, including the major box jellyfish Chironex fleckeri. Medical Journal of Australia. 2001;175:652-655