Stingers & things

Marine Envenoming – an Australian overview
by Chris Nickson, September 2010

Marine Envenoming


  • The marine world is a rich source of venomous and poisonous creatures – what’s on land pales in comparison…
  • The global impact of marine envenoming on human health and activities is largely unknown.
  • This overview is not comprehensive, we will focus on 4 types of envenoming:
  1. jellyfish-like creatures that sting (Cubozoans and Hydrozoans – true jellyfish are the Scyphozoans)
  2. Organisms that primarily cause paralysis (e.g. the Blue-ringed octopus)
  3. Painful fish envenoming (e.g. the Stonefish).
  4. Sea snakes

Box Jellyfish (Chironex fleckeri)

  • Chironex fleckeri is a cubozoan with a deserved reputation of being the most lethal venomous animal in the world. There have been about 70 deaths in Australia alone and related species (other chirodropids, or multi-tentacled box jellyfish) probably account for much greater mortality figures worldwide. Each organism has 60 tentacles, each up to 2 or meters in length, and each packed with up to 1500 cigar-shaped nematocysts per mm2!!!
  • Stings result in immediate severe pain, the characteristic cross-hatched markings are pathognomonic. Systemic envenoming occurs with extensive stings – cardiovascular collapse can occur within minutes, presumably due to toxin-mediated disruption of sodium and calcium channel flux. Other problems in survivors include delayed type hypersensitivity and the potential for permanent scarring.
  • In Northern Australia, stings usually occur when wading in water <1m deep. Deaths typically occur in remote locations, usually children. Stinger suits and stinger nets are useful preventative measures where available.
  • Copious application of vinegar and the removal of adherent tentacles, together with basic life support are the mainstays of first aid. Most stings require only simple analgesia and ice packs.
  • The effectiveness of CSL Box Jellyfish antivenom is unproven, its use in humans is based on anecdotal experience and case series. Doses given, preferably IV rather than IM, are: 6 ampoules (or whatever is available) for cardiac arrest, 3 ampoules for the haemodynamically unstable patient (repeat if required), and 1 ampoule for pain refractory to opioids.

Life in the Fast Lane links:

Irukandji Syndrome (Carukia barnesi and others)

  • Irukandji syndrome is a hypercatecholaminergic syndrome resulting from jellyfish envenoming. Classically the syndrome involves a mild initial sting with delayed onset of systemic symptoms after about 20 minutes. Symptoms include nausea and vomiting, as well as severe and often cyclical pain (affecting many parts of the body, including the abdomen, back, chest and limbs) and even priapism. Cardiovascular manifestations include severe hypertension and its complications, cardiomyopathy (with raised troponins) and acute pulmonary edema.
  • A causative organism was identified with the discovery of the tiny carybdeid (4-tentacled box jellyfish) Carukia barnesi by the intrepid Jack Barnes in 1963. Barnes demonstrating the causative role of this thumbnail-sized organism by stinging himself, his 9 year-old son and a local surf life-saver… All three were subsequently admitted to Cairns Base Hospital!
  • Irukandji-like syndromes may be found in many parts of the world other than Northern Australia. The syndrome may have different seasonal, environmental and clinical patterns in different regions, probably reflecting different causative species and human activites.
  • Following first aid treatment with vinegar, the mainstays of management are supportive care including analgesia (usually opioids such as IV fentanyl) and antiemetics (e.g. IV promethazine). IV glyceryl trinitrate may be a useful option for uncontrolled hypertension and acute pulmonary edema.
  • IV magnesium is commonly used for refractory pain and hypertension, but evidence of effectiveness is limited to anecdotal experience and small case series lacking methodological rigour.

Life in the Fast Lane links:

Blue bottles (Physalia spp.)

  • Physalia spp. (Portuguese Man O’ War, Blue-bottles) probably account for more marine envenomings than any other organism.
  • Physalia spp. are hydrozoans (related to stinging corals) and each ‘individual’ is actually a colony of separate organisms living cooperatively.
  • Stings involve rapid onset burning associated with linear or eliptical markings; pain lasts a few hours and envenoming is typically self-limiting and rarely serious.
  • Wash sting sites with sea water, not vinegar (unlike cubozoan stings).
  • Hot water (45C) for 15 minutes is proven to effectively decrease pain.

Life in the Fast Lane links:

Blue-ringed octopus (Hapalochlaena spp.)

  • The organism that inspired one on the worst movie titles of all time – Octopussy – is found throughout Australia and in many other other parts of the world. Envenoming is rare, and generally results from these cute little creatures being picked up out of their coastal rock pools. There have been 3 reported fatalities.
  • Severe envenoming may become manifest within minutes, resulting in a rapidly progressive symmetrical paralysis. The patient will remain conscious until the end stages of fatal respiratory failure…
  • The venom’s major component is maculotoxin, which is identical to tetrodotoxin. This is produced by bacteria and used as a poison or venom by many different species. Examples of tetrodotoxic organisms include fish (e.g. puffer fish), mollusks (e.g. sea slugs), worms (e.g. ribbon worms), amphibians (e.g. salamanders) and crustaceans (e.g. xanthid crabs). The conotxin of cone shell snails (Conus spp.) is chemically different, but has similar clinical effects to a blue-ringed octopus envenoming,
  • Appropriate first aid involves application of Pressure Immobilisation Bandages and basic life support.
  • The mainstay of treatment is respiratory support (e.g. intubation and ventilation) until paralysis resolves, typically within 24 hours.

Life in the Fast Lane links:

Stonefish (Synanceia spp.)

  • Many fish have venomous spines (e.g. Lionfish, Stingrays and Catfish), but the Stonefish, a master of camouflage, has the greatest notoriety. It is found throughout Northern Australia and 13 venomous dorsal spines, each with 2 venom glands. The venom contains a mixture of hemolysins, hyaluronidases, cytolytic toxins, and the vasoactive stonustoxin.
  • Stonefish envenoming causes severe local pain, swelling and a puncture wound. Non-specific symptoms such as syncope are usually a result of severe pain; true cardiovascular toxicity is exceedingly rare.
  • Most painful fish envemonings can be treated with submersion in hot (45C) water (this probably has a neuromodulatory effect, rather than causing toxin denaturation). Pharmacological analgesia and local or regional anesthesia are also options – beware of the potential for iatrogenic burns if local anesthesia is used in conjunction with hot water!
  • Wound care may require removal of foreign bodies, debridement and antibiotics to cover marine organisms.
  • CSL Stonefish antivenom may be used for severe pain – administer 1 ampoule for every 2 spine punctures. It is also though to be effective for some other fish envenomings, such as those caused by the Scorpionidae, like the Bullrout and Lionfish.

Life in the Fast Lane links:

Sea snakes (Hydrophiidae)

  • Sea snakes are found throughout the world. In Australia they all belong to the Hydrophiidae family, are found in most regions (except some regions of the southern coast and western Tasmania). Terrestrial snakes can also swim and bite people in the water…
  • Sea snake envenoming is rare, they are inquisitive but generally not aggressive. Bites occur when attempts are made to handle them (e.g. freeing from fishing nets).
  • Envenoming results in progressive descending paralysis and rhabdomyolysis over a period of hours.
  • Pressure Immobilisation bandaging is the mainstay of first aid.
  • Management involves supportive care and treatment with 1 ampoule of CSL Sea Snake antivenom.

Life in the Fast Lane links:

Finally, putting envemoning aside, there are also myriad ways of being poisoned by marine life… Check out Toxicology Conundrum 036 – Seafood Poisoning to find out more.

Anyone fancy a swim?


  1. Micrognome: Stingers & things Marine Envenoming – an Australian overview

  2. RT @precordialthump: Micrognome: Stingers & things Marine Envenoming – an Australi …

  3. Guest post by Chris Nickson on Marine Envenoming…nice read

  4. RT @micrognome157: Marine envenoming Stingers & things

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  6. RT @micrognome157: Stingers & things

  7. Stingers & things The quick and dirty guide to marine envenoming from the @micrognome

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