A 10-year-old girl's survival after an encounter with a box jellyfish in Queensland last year could be a one-of-a-kind story, experts say.

Rachael Shardlow was stung by the world's most venomous creature while swimming 23 kilometres upstream from the ocean mouth in the Calliope River, near Gladstone, in December.

Rachael's 13-year-old brother, Sam, pulled her onto the riverbank. She told him she could not see or breathe, and fell unconscious with the jellyfish's tentacles strapped to her limbs.

Zoology and tropical ecology associate professor at James Cook University, Jamie Seymour, says the girl's survival after such an extensive sting is unheard of.

"I don't know of anybody in the entire literature where we've studied this where someone has had such an extensive sting that has survived," he said.

"When I first saw the pictures of the injuries I just went, 'you know to be honest, this kid should not be alive'. I mean they are horrific.

"Usually when you see people who have been stung by box jellyfish with that number of the tentacle contacts on their body, it's usually in a morgue."

Associate professor Seymour says the university is interested to see how long it takes for Rachael to recover, as well as whether there are any long-term effects.

"From our point of view it's really useful information that you very seldom, if ever, get your hands on," he said.

Rachael's father, Geoff Shardlow, says his daughter has scarring as well as some short-term memory loss.

"We've noticed a small amount of short-term memory loss, like riding a pushbike to school and forgetting she's taken a pushbike," he said.

"The greatest fear was actual brain damage [but] her cognitive skills and memory tests were all fine."

Mr Shardlow says it is vital there are more jellyfish warning signs erected throughout central Queensland.