Box jellyfish (BJ) are a group of marine invertebrates of the Class Cubozoa, which include Chironex fleckeri, Carukia barnesi–irukandji jellyfish and Chiropsolmus quadrigatus, native to the warm waters of northern Australia and Indo-Pacific Ocean. Many–but not all–
can cause lethal injuries. The highest risk period is from October to
May. Once a tentacle adheres to skin, it pumps nematocysts with venom into the skin (bottom image is of a person who died of BJ injuries), causing the sting, intense pain and cardiovascular collapse in extreme cases
Management Topical vinegar is the only effective way to disable the BJ’s nematocyts and stop further discharge into the bloodstream
BJ have caused at least 5,568 recorded deaths since 1954, due to a high-molecular-weight dermatonecrotic venom, the nature of which is as yet unknown. Unlike true jellyfish which drift, BJ actively seek their prey.