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Portuguese Man of War

The Portuguese Man o' War (Physalia physalis), also known as the blue bubble, blue bottle, man-of-war, or the Portuguese man of war, is a jelly-like, marine invertebrate of the family Physaliidae.

The common name comes from a Portuguese war ship type of the 15th and 16th century, the man-of-war or caravel (in Portuguese, Caravela), which had triangular sails similar in outline to the bladder of the Portuguese Man o' War.

Not a Jellyfish

While the Portuguese Man o' War resembles a jellyfish, it is in fact a siphonophore: a colony of four kinds of minute, highly modified individuals, which are specialized polyps and medusoids.

The Portuguese Man o' War is infamous for having a painful sting, and for swarming in many hundreds. It is responsible for up to 10,000 stings in Australia each summer, particularly on the east coast, with some others occurring off the coast states of South Australia and Western Australia.

The stinging venom-filled nematocysts in the tentacles of the Portuguese Man o' War can paralyze small fish and other prey. Detached tentacles and dead specimens (including those which wash up on shore) can sting just as painfully as the live creature in the water, and may remain potent for hours or even days after the death of the creature or the detachment of the tentacle.

Stings usually cause severe pain to humans, leaving whip-like, red welts on the skin which normally last about 2 to 3 days after the initial sting, although the pain should subside after about 1 hour. However, the venom can travel to the lymph nodes and may cause, depending on the amount of venom, a more intense pain. A sting may lead to an allergic reaction.

There can also be serious effects, including fever, shock, and interference with heart and lung action. Stings may also cause death, although this is rare. Medical attention may be necessary, especially where pain persists or is intense, or there is an extreme reaction, or the rash worsens, or a feeling of overall illness develops, or a red streak develops between swollen lymph nodes and the sting, or if either area becomes red, warm and tender.

Sting Treatment

Research suggests that in the normal course the best treatment for a Portuguese Man o' War sting is:

  1. to avoid any further contact with the Portuguese Man o' War and to carefully remove any remnants of the creature from the skin (taking care not to touch them directly with fingers or any other part of the skin to avoid secondary stinging);

  2. to then apply salt water to the affected area (not fresh water, which tends to make the affected area worse);

  3. If eyes have been affected they should be irrigated with copious amounts of room temperature tap water for at least 15 minutes and if vision blurs, or the eyes continue to tear, hurt, swell, or are light sensitive after irrigating, or there is any concern, a doctor should be seen as soon as possible;

  4. to follow up with the application of hot water (45°C/113°F) to the affected area, which eases the pain of a sting by denaturing the toxins.

  5. Vinegar dousing has been shown to cause strengthening of nematocysts from the larger (P. physalis) man-of-war species (that is, increasing toxin delivery and worsening the symptoms) while in the case of nematocysts of the smaller species (which has less severe stings), vinegar has been confirmed to provoke hemorrhaging. Vinegar is therefore not recommended.

  6. The Portuguese Man o' War is often confused with jellyfish by its victims, which may lead to improper treatment of stings, as the venom differs from that of true jellyfish.