Portuguese Man O' War - Venom

Venom

This species and the smaller Indo-Pacific man o' war are responsible for up to 10,000 human stings in Australia each summer, particularly on the east coast, with some others occurring off the coast 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 that 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 that normally last 2 or 3 days after the initial sting, though the pain should subside after about an 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 function. Stings may also cause death, although this is extremely rare. Medical attention may be necessary, especially if pain persists or is intense, there is an extreme reaction, the rash worsens, a feeling of overall illness develops, a red streak develops between swollen lymph nodes and the sting, or either area becomes red, warm and tender.

The best treatment for a Portuguese man o' war sting is:

• 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); then
• To apply salt water to the affected area (not fresh water, which tends to make the affected area worse)
• To follow up with the application of hot water (45 °C/113 °F) to the affected area from anywhere between 15-20 minutes which eases the pain of a sting by denaturing the toxins.
• If eyes have been affected, to irrigate 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 show light sensitivity after irrigating, or there is any concern, to see a doctor as soon as possible.

Vinegar is not recommended for treating stings. Vinegar dousing increases toxin delivery and worsens symptoms of stings from the nematocysts of this species. Vinegar has also been confirmed to provoke hemorrhaging when used on the less severe stings of nematocysts of smaller species.

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.