The box jellyfish can kill a man in minutes. Linda Vergnani meets the researchers risking unimaginable pain to take the sting out of its touch.

Wearing overalls and latex gloves, Heather Walling enters the room marked "Danger, No Entry. Authorised Personnel Only" to feed transparent creatures as minute as grains of white pepper.

Warning me to stand clear, Walling - a research officer at the Cooperative Research Centre's Reef Research Centre based at James Cook University, north Queensland, Australia - hauls a dish from a seawater tank and places it under a microscope. Then she shows me one of her "babies", a tiny transparent jellyfish polyp that has suckered to the dish. The ethereal creature resembles an anemone, crowned by 11 gently waving tentacles. "Look at the stinging cells on the end of the tentacles," remarks Walling, a masters student in aquaculture. "They are huge, like stingers on steroids. Nobody knows how toxic they are. That's why I have to be so careful."

The dozens of youngsters she is rearing are polyps of the irukandji jellyfish, Carukia barnesi . The venom of the adult jellyfish, which is no larger than a grape, causes acute agony and very high blood pressure, which can lead to heart attack or stroke. Between 70 and 250 people are treated in hospital each year after being stung by irukandji jellyfish in the tropical waters off northern Australia. In 2002, two tourists to the Great Barrier Reef died after suspected irukandji jellyfish stings.

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This April, Walling and Lisa-ann Gershwin, a doctoral student at the Australian Institute of Marine Science, became the first people to successfully breed Carukia barnesi polyps in captivity. The polyps were hatched from eggs bred from about 200 adult jellyfish collected at two popular bathing beaches. Walling and Gershwin hope that the poison from the stings, which cover the polyps' tentacles and bells, could be used to develop an antivenin and analysed for possible pharmaceutical benefits.

So toxic are Carukia barnesi that even a glancing touch can cause irukandji syndrome. "I was paranoid when I first started working with these jellyfish. I would practically wrap myself in latex," Walling says. This summer, she had to individually feed 200 adult irukandji jellyfish in the laboratory. "You always have to wear your safety gear and know what you are doing. I'm very grateful I haven't been stung."

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The irukandji breeding project forms part of the ground-breaking research into the biology of box jellyfish at James Cook University, the CRC Reef Research Centre and the Australian Institute of Marine Science. Scientists are identifying new species of dangerous box jellyfish and are working with doctors to isolate toxins and find more effective treatment regimes for people who have been stung.

Members of the box jellyfish, or cubozoan family, range from minute irukandji to the melon-size predator Chironex fleckeri . Known as the world's deadliest marine animal, Chironex have killed at least 67 people in Australia in the past 100 years. Jamie Seymour, an applied ecologist and director of the Tropical Australian Stinger Research Unit, says: "These guys are impressive. They are without a doubt the most venomous marine creatures on the planet and can cause death within two to three minutes in a human."

A fully grown Chironex has 60 tentacles that can be up to 3m long. The billions of stinging cells on a single tentacle can kill an adult man.

Seymour, a senior lecturer in the School of Tropical Biology at James Cook's Cairns campus, notes: "If a standard jellyfish is a Mini Moke, the box jellyfish is a Formula One. We have seen them corral up fish like killer whales and one breaks through into the middle and grabs the fish."

Box jellyfish are found off northern Australia and around Indo-Pacific nations such as Malaysia. Each summer, Australian authorities erect special stinger nets on key beaches to prevent bathers blundering into patrolling Chironex . Ironically, people are often stung in these supposedly safe areas by the near-invisible irukandji that slip through the mesh.

Seymour has researched the life cycle of Chironex , finding that heavy summer rains trigger their transformation into medusa (jellyfish), while dry winters kill them off. He has also developed a computer program that accurately predicts the start and end of the Chironex season. Stinger nets were traditionally lifted in May, but he discovered that the season could go on until July.

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The Tropical Australian Stinger Research Unit is a multidisciplinary research body that consists of biologists, toxicologists and emergency physicians who take the "Know thy enemy" approach. As part of its work, Seymour is compiling an atlas of the stinging cells of different species of box jellyfish. So far, he has catalogued 19 of the 28 known species. Peter Pereira, director of emergency medicine at Cairns Base Hospital and a member of Tasru, says: "The stings are like a fingerprint. We can identify the species from them."

Seymour has been stung by both Chironex and Carukia barnesi . Dressed in a special neoprene and titanium suit, he was shown in a recent television documentary plucking Chironex from the water with his bare hands. He reckons this method of capture is not reckless, provided you pick them up by the bell and do not touch the stings. Yet his hands, chest and thighs have been scarred with the ladder tracks of accidental Chironex stings. He describes it as a surreal pain: "It's just like a red-hot knife dragging across your skin. Then intensify the pain ten times and hang on to it for 20 minutes." The irukandji sting, which is mild at first, kicks in after five to 30 minutes and causes days of agonising pain. Seymour was stung by an irukandji jellyfish on the lip while taking video footage of the creatures in the sea last year, although he was wearing his stinger suit, boots, mask and snorkel. "Boy, was I sick," he says. "I was in hospital for 18 hours. At times, I am sure that, if someone had given me a gun, I would have ended it." Pereira notes: "It is the worst pain most patients have ever experienced. Women say it is worse than labour pains."

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In May, professional diver Chris Ingham was stung by box jellyfish while diving on the outer reaches of the Great Barrier Reef. "It felt like a boa constrictor was wrapped around my chest," he says. Back on board the dory, he was hit by intense pains in his back, stomach and limbs. Then he started vomiting profusely and his legs collapsed under him. Lapsing in and out of consciousness, he was rescued by helicopter and flown to Cairns Base Hospital for treatment.

"I wouldn't wish the pain on my worst enemy," he says. "Every muscle and nerve ending was constricting. All my muscles were spasming, and my legs and arms were thrashing about. My skin and even my deep muscles felt as if they were being attacked by needles. It's a pain that goes right through your body." Ingham, who has dived for nine years, was so traumatised that he resigned from his job.

Gershwin is tracking down some of the culprits. She has identified nine new species capable of causing irukandji syndrome. Three she captured herself in the past few months on pearling boats off the port of Broome. On her latest trip, she was exhilarated when she caught 150 specimens of a larger, more virulent species of irukandji that plagues pearl divers.

Gershwin sent 100 frozen specimens of the as yet unnamed species to the Australian Venom Research Unit at the University of Melbourne so scientists could try to isolate the toxin. She predicts that anything from 100,000 to a million specimens may be needed to develop an antivenin - hence the importance of the breeding programme.

Ken Winkle, director of the Australian Venom Research Unit, says obtaining sufficient specimens is vital for determining the mechanisms of irukandji toxins. He believes doctors may be able to develop a treatment regime rather than an antivenin.

Back at the CRC Reef Research Centre, Walling and Gershwin's polyps should soon metamorphose into adult jellyfish, and the research into these deadly marine creatures will continue.

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