page_title: Box jellyfish
section_title: Danger to humans
hierarchical_section_title: Box jellyfish / Danger to humans
caption_attribution_description: Medicinal Vinegar
context_page_description: Box jellyfish are cnidarian invertebrates distinguished by their cube-shaped medusae. Some species of box jellyfish produce extremely potent venom: Chironex fleckeri, Carukia barnesi and Malo kingi. Stings from these and a few other species in the class are extremely painful and can be fatal to humans.
context_section_description: Although the box jellyfish has been called "the world's most venomous creature", only a few species in the class have been confirmed to be involved in human deaths, and some species pose no serious threat at all.
  In Australia, fatalities are most often caused by the largest species of this class of jellyfish, Chironex fleckeri. Researchers at the University of Hawaii's Department of Tropical Medicine found the venom causes cells to become porous enough to allow potassium leakage, causing hyperkalemia, which can lead to cardiovascular collapse and death as quickly as within 2 to 5 minutes. It was postulated that a zinc compound may be developed as an antidote.
  In Australia, C. fleckeri has caused at least 64 deaths since the first report in 1883, but even in this species most encounters appear to result only in mild envenoming. Most recent deaths in Australia have been in children, which is linked to their smaller body mass. In parts of the Malay Archipelago, the number of lethal cases is far higher (in the Philippines alone, an estimated 20-40 die annually from Chirodropid stings), probably owing to limited access to medical facilities and antivenom, and the fact that many Australian beaches are enclosed in nets and have vinegar placed in prominent positions allowing for rapid first aid. Vinegar is also used as treatment by locals in the Philippines.
  The recently discovered and very similar Chironex yamaguchii may be equally dangerous, as it has been implicated in several deaths in Japan. It is unclear which of these species is the one usually involved in fatalities in the Malay Archipelago. In 1990, a 4-year-old child died after being stung by Chiropsalmus quadrumanus at Galveston Island in the Gulf of Mexico, and either this species or Chiropsoides buitendijki are considered the likely perpetrators of two deaths in West Malaysia. Warning signs and first aid stations have been erected in Thailand following the death of a 5-year-old French boy in August 2014. A woman died in July 2015 after being stung off Ko Pha Ngan, and another at Lamai Beach at Ko Samui on 6 October 2015. At least two deaths in Australia have been attributed to the thumbnail-sized Irukandji jellyfish. Those who fall victim to these may suffer severe physical and psychological symptoms, known as Irukandji syndrome. Nevertheless, most victims do survive, and out of 62 people treated for Irukandji envenomation in Australia in 1996, almost half could be discharged home with few or no symptoms after 6 hours, and only two remained hospitalized approximately a day after they were stung.
  In Hawaii, box jellyfish numbers peak approximately seven to ten days after a full moon, when they come near the shore to spawn. Sometimes the influx is so severe that lifeguards have closed infested beaches, such as Hanauma Bay, until the numbers subside.
caption: A vinegar post in Queensland, Australia
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