New Zealand researchers excavating a 3000-year-old cemetery in Vanuatu say it may offer clues to why mysterious voyagers who sailed through Melanesia - creating the Polynesian race - travelled so fast.
One possibility was that they were trying to outrun the worst form of malaria - not realising they were carrying the parasite in their bloodstreams, says New Zealand paleo-pathologist Hallie Buckley.
Early analysis of the first skeletons found late last year has shown the people had a heavy burden of disease-causing organisms, in particular parasites that cause malaria.
Polynesia - bounded by Hawaii in the north, Easter Island in the east and New Zealand in the south - is malaria-free.
In Melanesia - Papua New Guinea, the Solomons and Vanuatu - malaria is endemic, although New Caledonia does not have it.
"In Polynesia there is no malaria, and as far as we know there never has been," Dr Buckley said yesterday in a phone interview. "And 3000 years ago malaria may not yet have been established in Vanuatu - so these people were carrying the disease with them."
US archaeologist Edward Gifford called the pre-Polynesian race "Lapita" after mishearing the indigenous name of a site in New Caledonia where he was working in 1952.
He linked distinctive pottery found at that site with shards of pottery found in New Guinea.
The Lapita finds are tied up with the origins of Polynesians in Taiwan, and before that, China, as originally pointed out by Peter Bellwood of the Australian National University when he linked the Lapita animals, ocean-going canoes and farming with people who appeared in southern China and Taiwan 6000 years ago.
His ideas were the basis of the "Express Train to Polynesia" theory: that farmers from the Amis "Austronesian" language group in Taiwan left there 5500 years ago and migrated to the Philippines, New Guinea and central Polynesia over 2000 years. They then began spreading north to Hawaii and south to New Zealand 1500 years ago.
But scientists have wondered why the pre-Polynesians moved from Taiwan through Melanesia relatively quickly, over just 500 years.
"One thought is they may have been looking for non-malarial areas to settle," Dr Buckley said. "But without knowing it, they were probably carrying the parasite with them."
She said that analysis of the skeletons should show whether they were fleeing the most dangerous malaria parasite - plasmodium falciparum - inserted into the blood when the anopheles mosquito pricks its needle into the human body.
The transition cycle is completed when the other mosquito bites an infected person to pass on many parasites.
"We will see if we can recover malaria DNA," she said. DNA analysis would show the relationships of these "Lapita" people with Polynesians, Melanesians and the Taiwanese aborigines such as the Amis language group thought to have started the initial voyages.
But it could also show a lot of information on the health of the people.
And stable isotope analysis was likely to show what specific diets the people had - a key issue in the debate over whether the "express train" travelled so fast that voyagers did not set up colonies along their route and grow crops, but relied on a hunter-gatherer lifestyle.
The skeletons so far found in Vanuatu, at Teouma, have included strongly muscled males and also evidence of severe joint damage, possibly caused by a genetic susceptibility to joint disease.