Chironex fleckeri
Kingdom-Animalia
Phylum- Cnidaria
Class- Cubazoa
Order- Cubomedusae
Family- Chirodropidae
Genus- Chironex
Species- fleckeri
Also known as the Sea Wasp or
Box jellyfish, the Chironex fleckeri is considered to be the most dangerous
jellyfish and one of the most dangerous venomous creatures in the world. An individual sea wasp enough venom to kill 60 adult
humans and can do so in only 3 minutes. It could kill more people than
crocodiles (the most dangerous land animal), sharks (the most dangerous fish),
and stonefish (the most venomous fish) all combined! They can grow to be as big as a
basketball, but they are square in shape, with 60 tentacles, each 15 feet long and 1/4 inch
thick. Sea wasps are strong swimmers and can swim in bursts of up to 5 feet per second, a velocity of 2m/sec and
acceleration of 40,000 x gravity. Found in the coastal areas of Northern
Australia, Africa, the Gulf of Mexico (near Texas), South-Eastern Asia, and
adjacent areas of the tropical Indo-west Pacific, the Chironex causes problems
for divers, surfers, and even small children swimming on the beach.
Chironex fleckeri is one of the simplest organisms. The bi-radially symmetrical body has well developed tissues and specialized cells. The outer covering of ectoderm made of milky slime substance and an inner layer of endoderm makes it displobastic. It has an organic exoskeleton and hydrostatic skeleton and it is an encephalized organism with a non-cellular mesoglea separating the two layers and spreading to a vast bulk of its body which aids its buoyancy. With only a single opening (the mouth and entrance to the cavity), the body encompasses a single sac-like body space called the Gastro-vascular cavity.
It often is pale-blue in color and almost invisible in the water
because it is transparent. It is called the box
jellyfish because its transverse section appears to be squared-umbrella -shape
with its tentacles at the
corners of the box margin. The edge of the umbrella turns inwards forming a circular shaped
structure
called Velarium. It possesses four dark spots (primitive eyes) that are sensitive to light.
These enable it to avoid
colluding with foreign objects, detection of foods, and orientation for swimming. It has a
simple but well-developed and sophisticated nervous and sensory systems but no specialized excretory
respiratory
and circulatory organs since most of its living cells are in direct contact with the water.
The tentacles are studded with microscopic stinging cells or capsules called Nematocysts or
Cnidoblasts. Nematocysts, or stinging cells, are used by jellyfish to deliver toxins
into their prey. They are believed to be secreted by the Golgi apparatus of the cytoplasm.
The stinging apparatus consists of a "harpoon" on a thread coiled inside the stinging
cell, and attached to a reservoir containing venom. On contact with the victim, the
stinging cell discharges its harpoon into the skin and injects venom. Each tentacle may be covered with millions of stinging
cells and can stretch to 5m resulting in a large amount of venom being injected over a wide area.
This characterizes it as being in the Phylum Cnidaria (cnidae means
threads).
The Chironex exhibits twin-phased metagenetic
development which is an alternation between a sessile
or stalked polyp and mobile medusa stages (the latter stage is however
predominant). The male and female sexes are difficult to tell apart by sight. It has gonads or sex organs
in the form of four crescent-shaped cells around the opening. During late Summer, matured males release sperm through the opening into the surrounding
water which is later absorbed by the females. The sperm reaches the ovary fertilizing the
eggs and thus forming zygotes that go into the oral arms of the cavity for further growth
into worm-like larva called Planula. The planula (pear-shaped) settles down on the sea bed attaching itself to the substratum
before metamorphosis into a polyp. This polyp then multiplies through vegetative
reproduction either by budding, stolonic growth and other cell divisions, forming a clone of
ciliated polyps. In Spring these will later change to medusa and migrate down the river
taking up pelagic or epipelagic life and grow into adults.
It swims freely in the water and alternately sink through the water pulsating vigorously like
a muscular parachute. The muscles at the margin of the box squeeze consistently to drive it
towards the surface and maintain buoyancy with the help of the mesoglea. The powerful contraction which provide the stately motion is controlled by the loose nerve
systems around the underside of the box without any controlling brain to aid coordination.
This animal is also a carnivore, even though it seems to be a passive predator. It
feeds on prey that
blunders into its track, but can as well seek out its victims. In fact, large active preys
such as sergestid prawns, shrimps, small fish swimming invertebrates and even other jellyfish
mostly those of Beroe species (comb jellies) all make nice meal for CF. It uses
its appendage called the Pedalium, which acts as the 'feeding hands' to reel the foods into its
gut after been stung to death with nematocysts inside the tentacles. Having no digestive
tract, the cilia in the digestive cavity move water, gases, dissolved foods around before
absorption. The digested food waste is later passed out through the same opening.
Although Chironex grows in clone during the polyp sexual stage, it exhibits a solitary life style. Its attacks on humans are definitely accidental since it does not feed on man. It probably tries to avoid them as well as other large fish (sharks ,barracuda etc.) but unfortunately, it cannot control the deadly darts being fired from its tentacles, since they are stimulated by physical pressure and proteinous chemical substance found on these victims just as on its preys. The pale-blue color that makes it almost invisible in the water and mucus secreting cells on its body, that produce slippery milky slime covering the entire body all make up a good protection for Chironex. It attacks by wrapping its tentacles full of deadly harpoon on the body of the victim making marks of welts on the affected areas. It then stings instantly releasing the toxin from the nematocysts into the bogy of the victim. However, this deadliness does not guarantee utter vulnerability. In fact, it serves CF better to avoid such enemies as rockfish, some species of seabirds, ocean sunfish and in particular, sea turtles which ironically, make the soft and deadly squishy stinger a harmless meal. Apparently, the toxin has no effect on them.
Attack on humans is identified with agonizing pain on the body, as painful as an acid attack
or extremely hot iron. With the release of its tentacles from the body, there appear welt marks on the
affected part of the skin. In some cases the tentacles hang on for a while posing greater danger as
the venom injected increases. 6-8 yards of welt length could easily kill an adult human. The aftermath is pain,
development of shock, fever, muscle cramps, numbness and paralysis and even death. With instant first aid
treatment, one may just experience controllable pain, fever, shock, rise in temperature, blistering
(urticae), and swelling. The injected toxin in the human blood stream leads to malfunctioning of heart muscle cells,
(non-rhythmical heart pulse rate), and subsequently shutting down the heartbeat.
Symptoms and signs of Chironex envenomation in humans include severe localized pain, often associated with vigorous attempts by the
patient to remove the tentacles (this may make the envenomation worse by causing the
discharge of further nematocysts), occasionally, nematocyst toxins cause lymph nodes near a sting site to
swell, and the patient might even become unconscious before they can leave the
water.
A
web site from Hawaii lifeguards give excellent first aid for box jellyfish
stings. They say that there are "two concepts are key to treating box jellyfish stings. One is
to prevent firing of any undischarged nematocysts remaining on the skin, thus preventing the injury from getting worse. The second is to treat the symptoms and pain caused by already-fired nematocysts. The following first aid treatment, based on current Australian research, is recommended for the stings of all species of box jellyfish:
1.Immediately flood the area with household vinegar to keep undischarged nematocysts from firing. This
does not relieve pain, but prevents additional stings.
2.Never rub the area with sand or anything else.
3.Irrigate exposed eyes with copious amounts of room temperature tap water for at least 15 minutes. If
vision blurs, or the eyes continue to tear, hurt, swell, or are light sensitive after irrigating, see a doctor.
4.Pluck off any vinegar-soaked tentacles with a stick or other tool.
5.If the victim has shortness of breath, weakness, muscle cramps, palpitations
or any other
generalized
symptoms, take them to an emergency room.
6.For pain relief, apply ice packs. If pain becomes unbearable, go to an
emergency room."
Some people may have said to use meat tenderizer, baking soda, papaya, or commercial sprays (containing aluminum sulfate and detergents) on nematocyst stings. The only problem is the fact that these substances may cause further damage. For instance, some kinds of meat tenderizer can cause skin peeling. Alcohol and human urine can both be harmful because in an Australian study report, they discovered that both alcohol and urine caused massive discharge of box jellyfish nematocysts.
There
are some precautions that one should take to avoid these deadly stings. Avoid swimming in areas where
Chironex is found during the jellyfish season (variable, but approximately September to March) and heed warning signs on beaches.
Avoid swimming alone or at remote beaches. Wear specially designed "stinger suits" while in known
Chironex waters. Swim at beaches patrolled by life savers, preferably equipped with vinegar, antivenom and basic resuscitation facilities.
Exercise caution on entering the water (do not dive or run into the water).
Strictly supervise children, who are more prone to stings, and whose lower body weight may render them more susceptible to the effects of the
venom. And finally swim at beaches that have been netted to exclude Chironex.
Knowing this, one should see
the awesome power of these animals and have respect for them. 
References
1. http://animaldiversity.ummz.umich.edu/cnidaria/cubozoa.html
2. http://www.pharmacology.unimelb.edu.au/pharmwww/avruweb/jellyfi.htm
3. http://www.wizvax.net/seawasp/subdirs/waspdef.html
4. http://www.mja.com.au/public/issues/dec2/fenner/fenner.html
5. http://www.aloha.com/~lifeguards/alsting1.html
6. http://library.thinkquest.org/C004086/other.htm
Amber McEldowney