CSL Antivenom Handbook

Jellyfish and Other Marine Animals

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General Principles

There are many species of jellyfish which can affect humans. The major Australian box jellyfish, Chironex fleckeri , is the only proven lethal species, for which there is an antivenom, and will be discussed in that section. There are several other species which can cause severe, maybe lethal, reactions. All jellyfish sting using individual stinging cells (nematocysts), and millions of these may discharge into a patient in a major jellyfish sting. Some of this venom may directly enter capillaries, so systemic envenoming can be very rapid indeed. Much less commonly, the venom may cause "allergic" type reactions in some people. Pain is not a universal diagnostic feature of all jellyfish envenoming, though it is the most common symptom.

Irukandji syndrome

This important response to stings by several probably related species of small and virtually invisible, tropical jellyfish (including Carukia barnesii) is typified by mild local pain, usually without skin marks. About 30 to 40 minutes later there may develop the typical syndrome of cramping muscle, back and abdominal pains, prostration, hypertension and occasionally, pulmonary or cardiac complications, notably pulmonary oedema. This is a most unpleasant condition and is potentially lethal. There is no antivenom. Hospitalisation is essential for the full blown syndrome. Early vinegar application is recommended for nematocyst inhibition.

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Jimble, Carybdea rastoni

A small 4 tentacled box jellyfish found commonly (but not exclusively) in southern Australian waters in summer, often in swarms. The sting is painful, with an angry red mark. Significant systemic effects are recently being reported from tropical waters.

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Morbakka, Tamoya sp.

A large 4 tentacled box jellyfish from tropical waters, which causes a very painful sting which may show cross hatching skin marks (as seen with Chironex fleckeri). Systemic envenoming may occur, including collapse, but there are no recorded deaths. There is no antivenom and vinegar is effective as first aid.

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Bluebottle, Physalia sp.

A medium sized "jellyfish" causing stings in northern and eastern Australian waters mainly, often in swarms. There is immediate pain lasting an hour or more, with typical elliptical blanched wheals and surrounding erythema. Mild or no systemic symptoms are usual, but a muscle-pain syndrome may occur. There is no antivenom. Vinegar or water discharges adherent nematocysts.

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Sea nettle, Chrysaora sp.

Moderate sized jellyfish which causes mild to moderate local pain, lasting up to several hours. Allergic reactions can occur. There is no antivenom and there is currently no substance which appears useful in first aid to inactivate nematocysts. Vinegar is not effective.

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Mauve stinger, Pelagia sp.

Large jellyfish, sometimes found in swarms, causing painful stings with wheals, pruritis and swelling. Appears to have allergenic venom. There is no antivenom.

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Hair jelly, Cyanea sp.

Very large jellyfish, causing moderate pain and redness of short duration, without systemic envenoming. There is no antivenom, vinegar is ineffective as first aid and should not be used.

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Cone shells, Conus sp.

Only a few cone shells, from tropical waters, are known to be hazardous to humans. Their venom contains a complex mixture of varied toxins, noteably the conotoxins. The envenoming occurs usually when the shell is picked up, and may result in local pain, potentially followed by systemic envenoming, with progressive paralysis and collapse requiring respiratory support. There is no antivenom.

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Blue ringed octopus, Hapalochlaena sp.

There are two species, found in all Australian coastal waters, often commonly. These are small octopuses which, when alarmed, develop vivid blue to purple rings on the body and tentacles. The saliva contains a potent neurotoxin, tetrodotoxin. Bites virtually never occur unless the octopus is removed from the water and placed on exposed skin. The bite may not be painful. Not every bite results in systemic envenoming, but paralysis, including respiratory paralysis, may develop quickly in severe cases, requiring urgent respiratory support on the beach. More often, the envenoming is less severe, with tingling around the mouth and mild weakness. There is no antivenom.

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Stingray injuries mostly occur when a person steps on the ray, either when climbing out of a boat in shallow sandy water or when running into such water. The stingray whips its poison barbed tail around, lacerating the foot or lower leg, sometimes leaving a portion of the barb behind. The mechanical injury can be severe, with fatal cases due to direct heart or bowel puncture or transection of major limb vessels. Nerve or tendon damage can occur. The venom causes intense local pain, which is heat susceptible, hence the value of hot water immersion as first aid. Always check the wound for foreign bodies, allow to close by secondary intention and consider prophylactic antibiotics. The severe local pain may require major analgesia or regional nerve block. There is no antivenom.

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Stinging fish

Many fish have venomous spines, which can cause severe local pain and occasionally, as in the case of stonefish, possible systemic symptoms. Hot water immersion, medical analgesia, removal of residual spine(s) and consideration of prophylactic antibiotics and tetanus immunisation are the mainstays of treatment. There is an antivenom for stonefish stings.

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Toxic fish

There are a number of toxins found in fish, some of which are potentially lethal. The best known is tetrodotoxin (Fugu poisoning) found in pufferfish and some related species. Eating these fish may result in classic neurotoxic poisoning, as seen with blue ringed octopus bites. Removal of fish from the stomach and cardiorespiratory support are the main modes of treatment in severe cases.

Ciguatera is the other common and well known fish toxin, probably produced by micro-organisms (dinoflagellates) and concentrated via the food chain, so that people eating large fish may be poisoned. The toxic fish appear and taste normal, the first indication of problems being the development of "food poisoning", with vomiting and diarrhoea, but also muscle cramps, joint pain and parasthesiae. In severe cases there may be prostration and these patients usually feel miserable and very weak. There is no antivenom and treatment is controversial. Support with iv fluids is usually helpful and there is some clinical support for the early use of iv mannitol, which appears to greatly moderate symptoms in severe cases.

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Sea snakes

There are many species of sea snakes in northern Australian waters, though bites are uncommon, as these purely aquatic snakes are generally inoffensive. They are front fanged and have potent venoms acting systemically. Both paralysis and severe myolysis with secondary renal failure may occur, depending on the species of snake involved. More details are given under the section on CSL sea snake antivenom.Coagulopathy is not observed.