A heart-stopping sting

James Cook University (JCU) student Stephanie Chaousis has discovered which part of box jellyfish venom will potentially kill humans.

Ms Chaousis has found that the jellyfish uses a two-step process. One part of the venom temporarily kills the victim, causing the heart to die but then recover and come back to life. The second part of the venom then takes over and kills the heart permanently.

The findings will have an impact on the treatment of people stung by box jellyfish, as well as opening up new possibilities for the development of drugs such as those used in heart transplants.

“After being stung by a box jellyfish medical aid should be given immediately, with prolonged CPR to maximise the chance of survival,” Ms Chaousis said.

Ms Chaousis has just completed her honours research project, supervised by Queensland Tropical Health Alliance (QTHA) researcher, Associate Professor Jamie Seymour based at JCU’s Centre for Biodiscovery and Molecular Development of Therapeutics.

“This discovery could be of great importance for use in heart transplants,” Associate Professor Seymour said. “Knowing that a component of the venom can cause a temporary heart standstill may lead to novel drug discovery for use in human heart transplants.”

Ms Chaousis used specialised equipment to separate the proteins in the venom and then tested the groups of different-sized proteins.

Testing on human heart cells, she found two protein groups that are responsible for toxic effects in humans. These two protein groups specifically attack human heart cells and in a high enough dose can stop the heart.

“The smaller the victim, the less venom is needed to cause death,” she said.

“It is really important to give CPR for as long as possible so the body has a chance to process the venom and, hopefully, recover.”

Ms Chaousis tested the cardiac effects of the larger protein and recorded 70 per cent cell death, followed by 100 per cent recovery after approximately four hours.

When she tested the cardiac effects of the smaller protein she found permanent cell death, measured over 10 hours.

“The next step will be to find out how the venom is acting on the cells, to figure out how they are causing death,” Associate Professor Seymour said.

Stephanie Chaousis has a Bachelor of Science in zoology and has recently completed her honours research project on box jellyfish venom, titled “Rapid short term and gradual permanent cardiotoxic effects of Chironex fleckeri (Box Jellyfish) venom.”

QTHA’s Associate Professor Seymour, a venom expert at JCU’s Centre for Biodiscovery and Molecular Development of Therapeutics, has just returned from collecting jellyfish venom to continue this research. “The venom is stored in the tentacles of the jellyfish. First we remove the tentacles and then extract venom from the stinging organelles,” he said.

Associate Professor Seymour said the dual-action venom enabled jellyfish to quickly stun, and ultimately kill, their usual food sources.

"Their venom enables a relatively slow-moving jellyfish to catch and kill a fast-moving shrimp or fish. We humans are not their prey. We are not their lunch. The fact that the venom has this affect on human hearts is just our bad luck. But this research indicates that we might one day be able to use proteins from the venom to help people undergoing heart surgery."