Warm Australian waters are home to the box jellyfish (Chironex fleckeri), which is considered to be one of the most venomous animals on the planet.
Box jellyfish stings lead to excruciating pain lasting days, tissue death and scarring at the site of the sting, and with significant exposure, death within minutes. While most jellyfish stings do not lead to death, pain and scarring is quite common.
Despite its potent ability to cause pain and death, to date we’ve had very little understanding of how this deadly venom works. This makes it very difficult to understand how it can cause so much pain – and how to develop medicines to block venom actions.
Published today, our new research has uncovered a potential antidote for box jellyfish venom. By working with humans cells and the gene-editing tool CRISPR, we identified a common, cheap drug that is already on the market and which could be a candidate for treating box jellyfish stings.
This work began in 2012, when we set out to determine what it was about box jellyfish venom molecules that made them so effective in causing pain and damage.
The venom didn’t seem to work through the known pathways that cause cell death. So we used CRISPR genome editing technologies in human cells grown in the laboratory. This let us systematically turn off each gene in the human genome, and test to see which of these is needed for the jellyfish venom to kill the cells.
It’s kind of like flipping all the switches in a house, trying to figure out which one turns off the kitchen lights, but at the whole genome level. We actually didn’t even know if it would be possible to find single genes that when turned off could block the venom action.
But luckily, we were successful. While normal human cells exposed to venom die in the laboratory within five minutes, we identified gene-edited cells that could last for two weeks continually exposed to venom.
Then using new DNA sequencing technologies (that allow us to identify CRISPR guide RNAs targeting specific genes), we identified which human genes had been switched off in our genome editing experiments.
By putting the evidence together, we worked out which genes the box jellyfish venom needs to target in order to kill human cells in the lab.
One we identified is a calcium transporter molecule called ATP2B1, and is present on the surface of cells.
We tested a drug that we know targets this gene. If we added the drug before the venom, we could block cell death, but if we added the drug after the venom, it didn’t have any effect.
So this helped us understand more about how the venom works – and maybe even how it causes pain. We are still looking at this particular pathway in more detail, but at the moment it doesn’t seem promising for a therapy.
Next we looked at the pathways involved in how box jellyfish venom kills cells.
We found four of the top ten genes required for venom action were all part of a pathway that makes cholesterol in cells.
Since cholesterol has been heavily studied over the last 30 years, there are already drugs available that target lots of different steps in cholesterol regulation. We focused on drugs that could bind to cholesterol and remove it quickly, basically acting like a cholesterol sponge.
We found these drugs could completely block the box jelly fish venom’s ability to kill human cells in the lab if added before venom exposure. We also found there is a 15-minute window after venom exposure where if we add this cholesterol sponge, it still blocks venom action.
This was exciting, as the capacity to have effect after the venom means the drug could work as a treatment in the case of being stung by a box jellyfish.
So far our additional studies show that these same drugs can block pain, tissue death and scarring associated with a mouse model of box jellyfish stings.
The really cool thing about this work is that the potential box jellyfish antidote we found is in a family of drugs called cyclodextrins. These are known to be safe for us in humans, and are cheap and stable.
So now we are trying to work with the state or national government, or first responders, to see if we can move this venom antidote forward for human use.
As well as developing a topical application at the site of a sting, we also aim to develop this idea as a potential treatment for cardiac injection in the emergency room in the case of very severe box jellyfish sting cases.
The Easter long weekend marks the last opportunity this year for many Australians to go to the beach as the weather cools down. And for some, particularly in Queensland, it means dodging bluebottle tentacles on the sand.
In just over a month this summer, bluebottles stung more than 22,000 people across Queensland, largely at beaches in the southeast. At least eight of these stings required hospitalisation.
To make matters worse, there were more than twice the number of Irukandji jellyfish stings in Queensland than is typically reported for this time of the season. Irukandjis – relatives of the lethal box jellyfish – cause “Irukandji syndrome”, a life-threatening illness.
There have also been widespread reports that Irukandjis have been migrating southwards. Many reports have assumed there is a southward migration linked to climate change. But Australia’s jellyfish problem is far more complex. Despite the media hype, there exists no evidence that any tropical Irukandji species has migrated, or is migrating, south.
In addition, many people find it surprising to learn there are Irukandji species native to southern waters. Many cases of Irukandji syndrome have been recorded in Moreton Bay (since 1893), New South Wales (since 1905), and even as far south as Queenscliff, near Geelong (in 1998).
So amid the misinformation, pain and misery, why is this jellyfish problem not more effectively managed?
In North Queensland, coastal councils have grappled with jellyfish risk for decades.
At popular beaches in the Cairns, Townsville, and Whitsunday regions, visitors are offered protection in the form of lifeguard patrols and stinger nets. Beaches are also peppered with marine stinger warning signs.
But these strategies are not as effective as intended. Stinger nets, for instance, protect people against the larger, deadlier box jellyfish, but not against the tiny Irukandji.
There’s a lack of public awareness about many aspects of stinger safety. For example, that Irukandji can enter the nets; that Irukandji may be encountered on the reefs and islands as well as in many types of weather conditions; and that both Irukandjis and box jellies are typically very difficult to spot in the water.
To make matters worse, visitors, especially international tourists, are completely unaware of these types of hazards at all. This was confirmed in a recently published study that found marine stinger warning signs are not effectively communicating the true risk.
The high number of stings that continue to occur at patrolled beaches highlights the need for a redesign.
Reef operators share a similar problem.
Workplace Health and Safety legislation requires businesses for recreational water activities to do all they reasonably can to protect their staff and customers from health and safety risks.
Jellyfish risk management is only mentioned in the Code of Practice applying to diving and snorkelling businesses. But jellyfish stings continue to be widely reported, raising questions about the effectiveness of this law and its applicability to businesses for other water activities like jet skiing, kayaking, and resort watersports.
Absolutely! But only with more data and communication about the risks of jellyfish.
A newly established independent Marine Stinger Authority, based in Cairns, will be well positioned to provide all coastal councils, government and tourism organisations, and the wider public with updated research, information and consultation on jellyfish risks in Australia.
Why your tourist brain may try to drown you
It’s a good start, and all current strategies provide a level of protection, but there is room for improvement. We have identified the following points as the highest priority:
1. a national reporting system
A national reporting system to capture real-time data about stings. This would inform coastal councils, tourism operators and other stakeholders so they can better protect the public and meet their duty of care.
Such a system has been partially developed by CSIRO, but this has ceased. We are seeking funding to resume development and implementation of this critical public safety tool.
2. improved warning signage
Modification of jellyfish warning signs should be consistent with research-based design guidelines.
Effective signs should, among other things: be noticeable and include a signal-word panel with “WARNING” in appropriate size and coulours to alert of the hazard; be easy to read, including by international visitors; include a well-designed pictogram indicating scale of hazardous jellyfish; and include hazard information, its consequences and how to avoid it.
Any modifications would also need to be monitored to ensure the signs are properly understood where deployed.
3. an updated Code of Practice
The Work Health and Safety Code of Practice should be amended to include all businesses for recreational water activities and make jellyfish risk management mandatory.
4. safety messaging research
More research is needed to better understand the effectiveness of jellyfish management strategies, taking into account the diverse cultural expectations and
languages of visitors at different destinations.
For this Easter break, here a few safety tips for beachgoers:
plan ahead and be aware of local conditions
don’t touch bluebottles or other jellyfish (they can still sting out of the water)
wear stinger protective clothing like a full body lycra suit (a “rashy”) or neoprene wet suit (especially in tropical areas)
pack a bottle of vinegar in your beach bag, boat or boot of the car
get local advice on recent stings (from lifeguards or tour operators).
Reports that Irukandji jellyfish might be moving south may be panicking people unnecessarily. It’s almost impossible to tell where the tiny jellyfish are along our coast, but that could change with new technology that can “sweep” the ocean for traces of DNA.
Since the Christmas period nearly twice the usual number of people have suffered the excruciating consequences of being stung by Irukandji. The stings are rarely fatal, but can require medical evacuation and hospitalisation.
These reports of southward movement are almost a yearly tradition, often sensational, and accompanied by varying expert opinions about whether climate change is driving these dangerous tropical animals south, towards the lucrative beach tourism destinations of southeast Queensland.
But simply counting the number of Irukandji found, or the number of reported stings, tells us very little about where the species can be found.
“Where are Irukandji located, and is that changing?”, might seem like a straightforward question. Unfortunately, finding the answer is not easy. The only definitive way to determine where they are is to catch them – but that poses many challenges.
Irukandji are tiny (most are about 1cm in diameter) and transparent. Along beaches they are usually sampled by a person wading through shallow water towing a fine net. This is often done by lifeguards at beaches in northern Queensland to help manage risk.
Irukandji are also attracted to light, so further offshore they can be concentrated by deploying lights over the sides of boats and then scooped up in nets. The problem is they’re are often very sparsely scattered, even in places we know they regularly occur, such as Queensland’s north. As with any rare species, catching them can confirm their presence, but failure to catch them does not guarantee their absence. Collecting Irukandji in an ocean environment is truly like searching for the proverbial needle in a haystack.
Another method is to infer their presence from hospital records and media reports of Irukandji syndrome, the suite of symptoms caused by their sting, but this method has major pitfalls. There is often a delay of around 30 minutes between the initial sting, which is usually mild, and the onset of Irukandji syndrome. Hence the animal that caused the symptoms is almost never caught and we cannot verify the species responsible.
Indeed, we do not know whether Irukandji are the only marine organisms to cause Irukandji syndrome. For example, the Moreton Bay Fire Jelly, a species of jellyfish related to Irukandji only found in southeast Queensland, and even bluebottles, which in the past couple of weeks have stung more than 10,000 people along Australia’s east coast, have also been suggested to occasionally cause Irukandji-like symptoms.
Emerging technology may be the key to properly mapping Irukandji distribution. All animals shed DNA in large quantities into their environment (for example, skin cells and hair by humans). This DNA is called environmental DNA) (or eDNA) and genetic techniques are now so powerful that they can detect even trace amounts.
In the sea, this means we can determine whether an animal has been in an area by collecting water samples and testing them for the presence of the target species’ DNA. This technology is exciting because it provides a major upgrade in our ability to detect rare species. Moreover, it is relatively simple to train people to collect and process water samples, the results can be available within hours, and the equipment needed to analyse the samples is becoming increasingly affordable.
This means an eDNA monitoring program could be easily established in Southeast Queensland to monitor the occurrence and, importantly, changes in the distribution of Irukandji jellyfish. This is because Irukandji leave traces of their genetic code in the water as they swim.
Developing the eDNA technology for use with Irukandji would cost a few hundred thousand dollars – a relatively small price to pay to improve public safety, to provide stakeholders with some control over their ability to detect Irukandji, and to create some certainty around the long-term distribution of these animals.
The authors would like to acknowledge the significant contribution to this article by Professor Mike Kingsford (James Cook University).
For most marine biologists, myself included, it wasn’t until 2005 that it dawned on us that a third of all human-caused carbon dioxide emissions are dissolving into and acidifying the sea.
By driving down seawater pH (and increasing acidity), these emissions are increasingly bad news for marine organisms that build their protective shells and skeletons out of calcium carbonate. When seawater becomes too acidic, calcium carbonate structures begin to corrode, dissolving baby oysters, coral skeletons, and many other creatures.
And while much has been written about the species that will lose out, a lot less has been said about the potential “winners” of ocean warming and acidification.
In a recently published paper, we present evidence that the slimy, jelly-like creatures of the oceans are far more tolerant of rising marine carbon dioxide levels. It is these creatures that are likely to proliferate in a warmer and increasingly acidic ocean.
Unfortunately for life in the sea, many of these lucky species are already considered a nuisance in marine ecosystems.
There are places already on Earth that show us what the future might look like. The waters surrounding some coastal volcanoes are high in CO₂ and low in aragonite (a form of calcium carbonate).
Volcanic activity causes CO₂ to bubble up (or “seep”) from the sea floor, acidifying large areas for hundreds of years. The tricky bit is finding carbon dioxide seeps without other minerals which confuse the story. But it can be done, and researchers have begun to study a number of these naturally acidified areas to understand which organisms thrive, and which are most vulnerable to ocean acidification.
We have found that chronic exposure to increases in CO₂ alters food webs and causes marine biodiversity loss around underwater volcanic seeps in the Mediterranean, the Sea of Cortez, and off Papua New Guinea. Key groups, like corals and hard, skeleton-building algae, are consistently compromised and fish reproduction is disrupted.
Meanwhile, higher CO₂ levels stimulate the growth of certain single-celled algae, seaweeds, and seagrasses. If temperatures remain low enough then the symbiotic algae of corals and anemones do well, as do numerous invasive species of animals and algae.
Some organisms have tissues that protect their shells and skeletons – including some corals in the tropics, and mussels in temperate seas – meaning they can tolerate acidified seawater. Yet these animals, despite being tough, can still experience adverse effects on reproduction, behaviour, respiration, and growth when carbon dioxide levels ramp up.
The fossil record serves as a warning. Shells found after high-CO₂ mass extinction events are much smaller than their ancestors — a phenomenon known as the Lilliput effect. Work at volcanic seeps has shown that smaller animals are better able to cope with the stress of ocean acidification.
And while the carbon boost provided by ocean acidification can drive up phytoplankton productivity, it can also harm tropical coral reefs. A fall in carbonate levels causes coral skeletons to dissolve, and increased CO₂ levels stimulates the growth of seaweeds that smother the reefs.
It is now clear that tropical coral reefs face a host of interconnected problems (bleaching, corrosion, disease, spreading seaweed, invasive species) that are all exacerbated by rising CO₂ levels.
Invasive species of algae and jellyfish thrive at the levels of carbon dioxide that are predicted to occur this decade. Our review of laboratory experiments reveals stand-out cases such as so called “Killer algae” (Caulerpa taxifolia). This species, which benefits from higher CO₂, is spreading world-wide and is so toxic that native herbivores die of starvation rather than eat it.
It turns out that loads of notorious nuisance species – such as Japanese kelp (Undaria pinnatifida) and stinging jellyfish (Pelagia noctiluca) — are resilient to rising CO₂ levels.
Global warming and changes in seawater chemistry may help the spread of hundreds of these damaging marine organisms.
Ocean acidification research is the new kid on the block amongst planetary environmental issues. But as evidence rolls in from across the globe it is clear that many organisms are likely to be affected, resulting in both winners and losers.
Both the decline of vulnerable species and the spread of harmful marine organisms should be factored into calculations of the risks of climate change and ocean acidification.
If we want to curb the spread of harmful marine life, like toxic algae and stinging jellyfish, then reducing CO₂ emissions is definitely part of the solution. This is why there is a growing awareness of the central role of ocean issues in climate negotiations at COP21 in Paris and beyond.
But local solutions to this global issue can also have a range of benefits. The International Union for the Conservation of Nature Blue Carbon initiative, for example, recognises the ability of coastal vegetation (e.g. saltmarshes and seagrasses) to prevent acid water run-off, and capture and store carbon – raising the pH of coastal waters. Other solutions include seaweed farming and the gradual restoration of mangroves in areas that have been converted to shrimp farms.
To properly address the crisis of our warming and acidifying oceans, we must attack this issue from every angle. It’s time we began thinking about the ways we can more sustainably work with, and for, our oceans in order to preserve life on Earth.