| Chironex fleckeri | |
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| Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Cnidaria |
| Class: | Cubozoa |
| Order: | Carybdeida |
| Family: | Chirodropidae |
| Genus: | Chironex |
| Species: | C. fleckeri |
| Binomial name | |
| Chironex fleckeri Southcott, 1956 |
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Chironex fleckeri, commonly known as sea wasp, the infamous lethally venomous species of Box jellyfish living in northern Australia's coastal waters, is the most lethal jellyfish in the world.[1][2]
The amount of venom in one animal is enough to kill 60 adult humans.[3]
First aid consists of washing the sting area with vinegar, and in no circumstance should alcohol, alcohol-based lotions, or methylated spirits be applied. Cardiopulmonary resuscitation (CPR) may be required. Medical help should be sought as soon as possible after considering these needs.
Notorious for its dangerous sting, C. fleckeri tentacles, up to 3m long, are covered in thousands upon thousands of nematocysts which on contact release microscopic darts, each delivering an extremely powerful venom. Being stung invariably results in excruciating pain, and if the sting area is significant, an untreated victim may die in as little as 3 minutes. Swimmers who are stung face the additional risk of drowning. [3]
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Description
Chironex fleckeri is the largest of the cubozoans (commonly called box jellyfish), many of which may carry similarly toxic venom. Its bell grows to about the size of a basketball, and trails four clusters of 15 tentacles trailing from each of the four corners of the bell. The pale blue, virtually transparent creature is nearly impossible to see in its habitat, posing particular danger to swimmers.
When the jellyfish are swimming the tentacles contract so they are about 15 cm long and about 5 mm in diameter; when they are hunting, the tentacles are thinner and extend to about three meters long. The tentacles are covered with a high concentration of stinging cells called nematocysts which are activated by pressure and a chemical trigger: they react to proteinous chemicals. Box jellyfish are day hunters; at night they are seen resting on the ocean floor 'sleeping'. However, this 'sleeping' theory is still debated.[citation needed]
In common with other box jellyfish, Chironex fleckeri have four eye-clusters with twenty-four eyes. Some of these eyes seem capable of forming images, however it is debated whether they exhibit any object recognition or object tracking; it is also unknown how they process information from their sense of touch and eye-like light-detecting structures due to their lack of a central nervous system.
Chironex fleckeri live on a diet of prawns and small fish and are themselves prey to turtles, whose thick skin is impenetrable to the nematocysts of the jellyfish.
Distribution and habitat
The polyps are found in estuaries in northern Australia. The medusa is pelagic and is found in the coastal waters of northern Australia and adjacent areas of the tropical Indo-West Pacific, and are also found in southeastern Asia. They are not usually found on the reef.
Sting
Chironex fleckeri is best known for its incredibly powerful and often fatal sting. The sting produces excruciating pain accompanied by an intense burning sensation, and the venom has multiple effects attacking the nervous system, heart and skin at the same time. While an appreciable amount of venom (contact from about ten feet or three metres of tentacle) needs to be delivered in order to have a fatal effect on an adult human, the potently neurotoxic venom is extremely quick to act. Fatalities have been observed as little as four minutes after envenomation, notably quicker than any snake, insect or spider, and prompting its description as the world's deadliest venomous animal. Frequently a person swimming who gets stung will have a heart attack or drown before they can even get back to the shore or boat.
If a person does manage to get to safety, treatment must be administered urgently. Dousing a sting with vinegar immediately inhibits any nematocysts which have not been activated,[4] whereas rubbing a sting or dousing with alcohol can encourage nematocysts to activate. After dousing with vinegar, rescue breaths and CPR may be required; for less serious stings, treatment with ice packs and antihistamines is an effective method of pain relief. [5]Adhering tentacles should be removed carefully from the skin using protected hands or tweezers. Removed tentacles remain capable of stinging until broken down by time and even dried and presumably dead tentacles can be reactivated if wettened. The Australian snake bite treatment of using roller bandages to bandage the affected limb (with the aim of preventing distribution of the venom through the lymph and blood circulatory systems) was no longer recommended for box jellyfish envenomation after 2005. The change was prompted by research which showed that using bandages to achieve tissue compression provoked nematocyst discharge, despite the use of vinegar.
An antivenom to the Box Jellyfish's sting does exist. After the immediate treatment described above, it must be administered quickly. Hospitals and ambulance services near to where the jellyfish live possess it, and must be contacted as soon as possible. The jellyfish's venom is so powerful, however, that even if the victim does get to safety and have the immediate treatment given and contact the ambulance, they may die before the ambulance reaches them.
The box jellyfish is estimated to be the cause of at least one death a year in Australia, and the record has been set to about 67 or more.
Chironex fleckeri and other jellyfish, including the Irukandji (Carukia barnesi), are abundant in the waters of northern Australia during the summer months (November to April or May). It is believed they drift into the aforementioned estuaries to breed. Signs like the one pictured are erected along the coast of North Queensland warning people of such, and few people swim during this period. Some people still do, however, putting themselves at great risk. At popular swimming spots, net enclosures are placed out in the water wherein people can swim but jellyfish cannot get in, keeping swimmers safe. The much smaller (but generally non-lethal) Irukandji, however, can pass through the nets and no known antivenom for its sting has been developed yet.
References
- ^ Fenner, Peter J.; John A. Williamson (December 1996). "Worldwide deaths and severe envenomation from jellyfish stings". Medical Journal of Australia 165 (11–12): 658–61. ISSN 0025-729X. http://www.mja.com.au/public/issues/dec2/fenner/fenner.html#map. Retrieved 2009-09-04. "The chirodropid Chironex fleckeri is known to be the most lethal jellyfish in the world and has caused at least 63 recorded deaths in tropical Australian waters off Queensland and the Northern Territory since 1884".
- ^ http://www.environmentalgraffiti.com/offbeat-news/the-worlds-5-most-venomous-species/697
- ^ a b Biology, 7ed. Campell & Reece
- ^ http://www.ncbi.nlm.nih.gov/pubmed/1352619?dopt=AbstractPlus
- ^ http://www.outback-australia-travel-secrets.com/box-jellyfish.html
External links
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Wikimedia Commons has media related to: Category:Chironex fleckeri |
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This article's external links may not follow Wikipedia's content policies or guidelines. Please improve this article by removing excessive or inappropriate external links. |
- Chironex fleckeri on fccj.org
- Emergency treatment
- Inactivation of nematocysts using acetic acid
- Australian Institute of Marine Science - Sea wasp information page
- Marine Medic page about box jelly and other Australian poisonous marine creatures
- Management of various animal envenomations including box jelly
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