A centipede found in many Townsville backyards might hold the key to protecting shellfish fanciers from a chemical so deadly that the United Nations has banned it.

Saxitoxin, the poison that causes paralytic shellfish poisoning or PSP, is so potent the UN Chemical Weapons Convention lists it among the leading chemical weapons of war. This forced the banning of much research until recently.

AIMS scientist Dr Lyndon Llewellyn became interested in saxitoxin, which kills hundreds of people worldwide every year, while studying in the United States, although he had to suspend his work until the research ban was lifted.

Dr Llewellyn’s work involves finding a protein able to detect saxitoxin so he could develop a cheap, reliable test kit. Now a garden centipede is his most treasured pet.

"Because PSP is so deadly I wanted to find a way to detect saxitoxin before people consumed the poisoned shellfish," he said.

"A garden centipede, found in most backyard compost heaps, contains the protein I needed to continue my research," he said.

Saxitoxin, found in a variety of molluscs and crabs that have been exposed to water-borne algal blooms, attacks the nervous system but does not affect the brain. The victim is fully aware of what is happening, but as the name suggests, becomes paralysed.

"Up to 40 per cent of people contracting PSP die, some within two hours, because the toxin eventually paralyses the diaphragm" said Dr Llewellyn.

World health organisations suggest that less than one part per million of toxin per 100g of shellfish meat will kill an average human. In the Philippines, children have died from as little as 0.4 ppm.

Dr Llewellyn suggests cultural differences are a contributing factor in people contracting PSP.

"People in the worst affected regions, Alaska, Chile, and the Philippines, gather a lot of their seafood, placing themselves at risk.

"The toxin is heat stable and water soluble, and people from these countries are known to have died from concoctions of seafood made into a soup," he said.

Australia has no deaths reported from PSP; however there have been two minor cases recorded in Tasmania. Dr Llewellyn is sceptical about there being only two cases in Australia. He believes a lot of cases are unreported and treated as an allergy.

A family of crabs native to Australia and common on the Great Barrier Reef can be as deadly to humans as any large sea animal. The green shawl crab is only 3cm across the carapace, but can have enough saxitoxin to kill 3,000 people.

Shellfish, both farmed and free range, accumulate saxitoxin after consuming algal bloom while feeding.

Dr Llewellyn said algal blooming is not restricted to seawater and can happen in fresh water, thus rendering freshwater shellfish toxic.

Because PSP tends to affect people in poorer countries Dr Llewellyn saw the need for a portable test kit that was cheap and easily accessible worldwide.

"When researching for the protein I tested amphibians, fish and reptiles without much success. Plenty had the protein but it did not have the properties to be commercially viable," he said.

Out of frustration, Dr Llewellyn decided to go terrestrial, beginning with the garden centipede. "I was turning my compost heap; a centipede stuck its head up so I took it and tested it."

His research has shown that five centipedes contain enough protein to test 30,000 samples for PSP.

Dr Llewellyn’s test will be as simple as taking a sample from shellfish and placing it on a card, where a colour code will indicate toxicity immediately.

The kit will also be of value to commercial operations around the world. Countries that export shellfish are forced to monitor for toxicity because of the consequences for their economy should they export toxic products. New Zealand alone spends $1 million each year on monitoring.

Australia imported $13 million worth of molluscs during the past financial year, mostly from New Zealand.

"The only authorised testing method at the moment is by injecting mice, which is barbaric," Dr Llewellyn said.

"Those tests, conducted in a laboratory, cost $200 to $300 each. My test kit will cost about $1 for material and is portable."