Until this year the sting of the peanut-sized, translucent Irukandji jellyfish found off far north Queensland was thought to be little more than a painful irritant.

Then it was accused of killing Briton Richard Jordan and American Robert King.

The verdict puzzled experts who knew the box jellyfish's venom could trigger the so-called Irukandji syndrome, causing excruciating back pain, sweating, and nausea, but not death.

Following tests, experts cleared the Irukandji jellyfish, or Carukia barnesi, of King's death -- but in the process discovered there are undetected, more deadly jellyfish lurking in Australian waters, with no antivenom available.

Jamie Seymour, a jellyfish expert with James Cook University's School of Tropical Biology in Cairns, said the stinging cells he tested from King were a mystery.

"This sting was from a jellyfish I've never seen before. It is a totally new species and opens up the floodgates as we just don't know what is out there," Seymour told Reuters.

Marine scientists now fear there could be up to six other species of Irukandji, on top of the Carukia barnesi, undetected in the waters off northern Australia that cause a deadly variety of Irukandji syndrome.

MYSTERY SICKNESS

King, 44, died in April when a sting received while diving on the Great Barrier Reef brought on a rapid rise in his heart rate and blood pressure, leading to a cerebral hemorrhage.

Jordan, 58, from Yorkshire, died in January after being stung swimming off Queensland's Hamilton Island. The sting aggravated an existing heart condition and no extra tests were conducted.

Authorities suspect the deaths were not the first fatalities from Irukandji stings in Australia, just the first recorded, as symptoms after a sting resemble decompression, a stroke or other conditions that may be listed as the cause of death.

"There is no doubt others have died from stings but people weren't in the know until now," Dr. Peter Fenner, co-founder of the International Consortium of Jellyfish Stings, told Reuters.

"But with this publicity, people remember the times divers collapsed and died on beaches with heart attacks blamed."

The first recording of Irukandji syndrome was noted in northern Australia by a doctor during the 1940s.

But the mystery set of illnesses was not named until 1952 when it was identified by Dr. Hugo Flecker, who traced the world's deadliest jellyfish, the Chironex fleckeri, a larger relative of the Irukandji which has killed 67 people in Australia.

He named the syndrome after the Aboriginal people of the Irukandji tribe living at Palm Cove, about 25 km (16 miles) north of Cairns, who for generations knew of an invisible danger in the water that could trigger a strange sickness.

They suspected they had been bitten by something in the sea but they did not know what, with the sting barely noticeable at the time and the pain not kicking in for about 30 minutes.

CURIOUS DOCTOR

It was not until 1966 that Cairns doctor Jack Barnes, who is now dead, found the culprit.

For several hours he lay on the seabed, weighed down with diving gear, looking for what he suspected was a tiny, transparent marine creature. His patience paid off.

He spotted a tiny jellyfish, its bell measuring just one inch across, with stinging cells on its body as well as its four, 20-inch long tentacles.

To test his theory, Barnes stung himself, his 14-year-old son and a local lifeguard. All three were rushed to the intensive care unit of a nearby hospital but survived.

The culprit was named in the doctor's honor, Carukia barnesi, and is commonly known as the Irukandji jellyfish -- one of about 15 box jellyfish known in Australia and 24 globally.

Irukandji syndrome has also been recorded elsewhere, across the Indian and Pacific oceans, but not as often as in Queensland where hordes of tourists a year are attracted to the pristine tropical beaches and the Great Barrier Reef to dive and snorkel.

Every year, between November and May, about 30 people are taken to hospital in far north Queensland suffering from Irukandji syndrome but a lack of research funding has hindered progress in finding an anti-venom.

Instead the Chironex fleckeri, the world's most venomous marine creature, has been favored for research, along with the long list of other deadly creatures in Queensland, ranging from sharks and crocodiles to sea snakes, stone fish and spiders.

But this year the numbers seeking treatment jumped to about 200 -- with two deaths -- as the tiny jellyfish was washed ashore from its usual deep waters by prevailing currents and winds, slipping through protective nets shielding beaches.

Seymour said the deaths sparked a new interest in jellyfish, with the federal government committing $56,000 for further research which was hoped to attract private sector funds.

"We desperately need research funds because until we know what kind of jellyfish there are, how can we produce antivenom for them," Seymour said.

"The last few months have shown that we really know nothing about what is going on with box jellyfish."

The Original Story from: yahoo