A number of tourists were treated for 'Jellyfish' stings on beaches around the resort of Patong on the southwest coast of Phuket island, Thailand, on Sunday 21 October 2018. The stings are thought to have been caused by the Portuguese Man o' War, Physalia physalis, or Indo-Pacific Portuguese Man o' War, Physalia utriculus, which are technically colonial Siphonophores rather than Jellyfish. All of the victims are described as having responded well to first aid given by coastguards, with none requiring hospital treatment.
A young tourist being treated for a Portuguese Man o' War sting on Patong Beach, Phuket, on 21 October 2018. The Thaiger.
Portuguese Man o' War are colonial Siphonophores only distantly related to true Jellyfish, Scyphozoa, though commonly referred to as such. Their bodies are made up of thousands of individual zooids, each with their own sting, tentacles and digestive system. New zooids are formed by budding from other members of the colony, but remain attached to these to form a single colony. Each year a generation of specialist sexual zooids (gonozoids) is produced which produce eggs and sperm, with fertilised eggs going on to form new colonies. These animals are anchored to the sea surface by a highly modified zooid which forms an air sack, filled with a mixture of carbon monoxide defused from the zooid and nitrogen, oxygen and argon from the atmosphere, which are brought into the sack through osmosis. Portuguese Man o' War produce an extremely strong venom, for both capturing food and defending the colony, and which is capable of causing extremely painful stings, and sometimes death, in Humans, for which reason people are advised to be extremely cautious on beaches where these animals wash up, not just of entire animals but also detached tentacles, which are less visible but still capable of stinging.
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