Irukandji syndrome is a medical condition induced by the sting of Carukia barnesi, the Irukandji jellyfish, as well as other cubosoans. Irukandji is the name of an aboriginal tribe that once lived in the Palm Cove north of Cairns in Queensland. Stings were very frequent in the area around where the Irukandji lived.
Irukandji syndrome is a condition induced by venomization by the sting of Carukia barnesi, a species of Irukandji jellyfish, and certain other box jellyfish. Similar to other box jellyfish stings, first aid consists of flushing the area with vinegar to neutralize the tentacle stinging apparatus.
In the year 1952, Hugo Flecker named Irukandji syndrome to describe the set of severe and dramatic systemic symptoms that happen around half an hour after a person is stung. These symptoms include the following:
The year of 1964 found Dr. Jack Barnes confirming the cause of the syndrome to be due to the small, box-shaped Irukandji jellyfish. To prove that the jelly fish was the cause of the syndrome, Dr. Barnes captured one and deliberately stung himself, his son, as well as a local lifeguard; he then observed the symptoms. All three of them ended up in the hospital. The tiny jelly fish was later called, 'Carukia barnesi.'
Recent research suggests this syndrome is caused by at least five or six small carybdeids similar to C. barnesi and two larger crybdeid jellyfish species. Carukia barnesi, the first jellyfish shown to cause Irukandji syndrome, is a member of the class, 'Cubozoa,' genus Carukia, family Carybdeidae. The Carukia is a small and clear jellyfish measuring twenty millimeters in diameter and twenty-five millimeters in the depth of its bell. There are four tentacles - one from each corner, which contain a large number of stinging cells called, 'nematocysts.' The tentacles might extend from five centimeters to one meter in length, depending on the degree of contraction. The bell of the Irukandji (Carukia) also contain nematocysts. Carukia barnesi have stinging cells on both tentacles and body.
Every one of the numerous nematocysts are akin to tiny, spring-loaded hypodermic needles. Contact with a person's skin causes the nematocyst to discharge and inject a tiny amount of venom that is highly potent. The more contact, the greater the amount of venom injected. The Irukandji is rarely seen prior to a person being stung due to their small size, which is around the size of the end of a person's thumb, and the almost transparent appearance of their body - which is nearly invisible in water.
The Carukia is an open water creature that is found in deeper waters of the reef and the islands at depths of up to ten to twenty meters, yet prevailing currents and winds may sweep the Carukia inshore, causing a relative mass stinging of swimmers. What this means is the jellyfish are found not only offshore, but along coastal beaches. Irukandji stings have been confirmed in shallow water as little as thirty millimeters deep where they become concentrated at the edge of the water. The number of jellyfish in inshore waters may vary from year to year, most likely due to changing weather conditions.
The jellyfish are found in the tropical waters off of the west and east coasts of Australia however - reports of Irukandji syndrome have come from different locations around the world such as:
The jellyfish are largely restricted to areas located between the Tropic of Cancer and the Tropic of Capricorn. The distribution may be far wider. Carukia barnesi has been shown to cause illness ranging from local symptoms to severe Irukandji syndrome with cardiac dysfunction. The sting is often times barely noticed and is only moderately irritating or painful in marked contrast to the Chironex with its immediate and excruciating pain.
The sting increases in intensity for a few minutes, it then decreases after about a half of an hour. A red colored, five to seven centimeter reaction then surrounds the area of contact within a few minutes. Small, 'papules,' or pimples appear like a cluster or a line of dots that mirror the position of stinging cells on the animals. They reach their maximum in approximately twenty minutes and then subside. Yet a complex of typical systemic symptoms starts following a latency of around thirty minutes on average.
Treating Irukandji Syndrome
Most people are able to be discharged from the hospital within twenty-four hours after their symptoms have settled. A syndrome of muscle aches and malaise might take up to more than a week to completely resolve. People with an underlying heart condition or Seniors would be at an increased risk of major morbidity or death from Irukandji syndrome. The syndrome has been misdiagnosed as decompression illness or a heart attack.
Severe hypertension at times causes a fatal brain hemorrhage. People commonly require hospitalization for management of high blood pressure and serious pain. A sting by Carukia barnesi does not necessarily result in Irukandji syndrome. Factors affecting venom load such as thickness of the keratinized skin, length of the tentacles involved, presence of hair, duration and pressure of the contact between tentacle and the person's skin have been proposed.
The precise mechanism of action of Irukandji venom remains an unknown. It has been suggested that, 'catecholamine excess,' or an increase in circulating noradrenaline and adrenaline might be an underlying mechanism in severe Irukandji syndrome. First aid consists of promptly flushing the area with vinegar to inactivate stinging cells present on the person's skin and to prevent additional envenomation.
Nematocysts of the Irukandji (Carukia) are inactivated by vinegar. The effects of vinegar in treating an Irukandji envenomation might be limited because of the delay in recognizing the sting. After the symptoms become obvious, it seems there are few if any active nematocysts left on the person's skin; however, vinegar would appear to be a responsible first aid measure if it is available. There is no anti-venom - treatment is largely supportive. Due to the fact that it is impossible to eradicate jellyfish in water, people must learn to live with these animals and heed information regarding their presence in the areas where they are going to swim.
Irukandji Jellyfish, Iracongi Jellyfish