What is Irukandji syndrome?
Irukandji syndrome is a severe reaction caused by the sting of tiny Irukandji jellyfish in tropical Australian waters. It brings intense pain, vomiting, sweating and dangerously high blood pressure.
Irukandji jellyfish are box jellyfish with bells often only about one to two centimetres across, smaller than a fingernail. They are almost invisible in the water and can be found both near shore and on outer reefs.
The sting itself may feel mild at first, but about 20 to 40 minutes later the syndrome begins, with severe back and muscle pain, cramps, anxiety and a racing heart. In rare cases, it can cause heart failure or bleeding in the brain.
Treatment and prevention
There is no antivenom. Treatment focuses on pain relief and controlling blood pressure in hospital. Vinegar is poured on the sting site to stop more stinging cells firing.
The syndrome is named after the Irukandji people of the Cairns region. In 1964, Dr Jack Barnes proved its cause by deliberately stinging himself, his son and a lifeguard.
Swimmers in the tropics are advised to wear full-length stinger suits, especially from about October to May, and to follow lifeguard advice. Stinger nets reduce but do not eliminate the risk, as Irukandji can pass through them.
Did You Know?
The species Carukia barnesi is named after Dr Jack Barnes.