Scientists have found the earliest known evidence of infection with a parasitic worm, that now afflicts more than 200 million people worldwide, in a skeleton more than 6,000 years old.
Archaeologists discovered a parasite egg near the pelvis of a child skeleton in northern Syria and say it dates back to a time when ancient societies first used irrigation systems to grow crops. Scientists suspect the new farming technique meant people were spending a lot of time wading in warm water - ideal conditions for the parasites to jump into humans. That may have triggered outbreaks of the water-borne flatworm disease known as schistosomiasis.
“The invention of irrigation was a major technological breakthrough (but) it had unintended consequences,” said Gil Stein, a professor of Near Eastern archaeology at the University of Chicago, one of the report's authors. “A more reliable food supply came at the cost of more disease,” he wrote in an email.
People can catch the flatworm parasite when they are in warm fresh water; the tiny worms are carried by snails and can burrow into human skin. After growing into adult worms, they live in the bladder, kidneys, intestines and elsewhere in the body for years. The parasites can cause symptoms including a fever, rash, abdominal pain, vomiting and paralysis of the legs. These days, the disease can be easily treated with drugs to kill the worms.
In pictures: 12 amazing archaeological discoveries
In pictures: 12 amazing archaeological discoveries
1/12 Ancient forest, discovered in February 2014
Ancient forest revealed by storms. The recent huge storms and gale force winds that have battered the coast of West Wales have stripped away much of the sand from stretches of the beach between Borth and Ynyslas. The disappearing sands have revealed ancients forests, with the remains of oak trees dating back to the Bronze Age, 6,000 years ago. The ancient remains are said by some to be the origins of the legend of ‚Cantre‚r Gwealod‚ , a mythical kingdom now submerged under the waters pif Cardigan Bay
2/12 Medieval royal palaces, discovered in November 2014
Archaeologists in southern England have discovered what may be one of the largest medieval royal palaces ever found – buried under the ground inside a vast prehistoric fortress at Old Sarum. The probable 12th century palace was discovered by archaeologists, using geophysical ground-penetrating ‘x-ray’ technology to map a long-vanished medieval city which has lain under grass on the site for more than 700 years
3/12 The Dead Sea Scrolls, discovered ca. 1950
The Dead Sea Scrolls are almost 1,000 biblical manuscripts discovered in the decade after the Second World War in what is now the West Bank. The texts, mostly written on parchment but also on papyrus and bronze, are the earliest surviving copies of biblical and extra-biblical documents known to be in existence, dating over a 700-year period around the birth of Jesus. The ancient Jewish sect the Essenes is supposed to have authored the scrolls, written in Hebrew, Aramaic and Greek, although no conclusive proof has been found to this effect
4/12 Diamond, discovered in March 2014
This rare diamond that survived a trip from deep within the Earth's interior confirmed that there is an ocean’s worth of water beneath the planet’s crust
5/12 Whale skeletons, discovered in February 2014
Chilean and Smithsonian paleontologists study several fossil whale skeletons at Cerro Ballena, next to the Pan-American Highway in the Atacama Region of Chile
6/12 Complete mammoth skeleton, discovered in November 2012
The first complete mammoth skeleton to be found in France for more than a century was uncovered in a gravel pit on the banks of the Marne, 30 miles north-east of Paris. Picture shows experts at work making a silicon cast of the mammoth's tusk
7/12 Million-year-old human footprints, discovered in February 2014
Photograph of the footprint hollows in situ on the beach as Happisburgh, Norfolk
8/12 Terracotta warrior, discovered in June 2010
Chinese archaeologists unearthed around 120 more clay figures in June 2010 excavations at the terracotta army site that surrounds the tomb of the nation's first emperor in the northwestern Shaanxi Province
© Jason Lee / Reuters
9/12 Neolithic 'lost avenue' - prehistoric stone circle, discovered in September 1999
The discovery of a Neolithic 'lost avenue' was described as one of the most important finds of the last century. Since the 1700s, archeologists and historians have argued over the existence of the huge sarsen stones, which were unearthed at the site of the world's biggest prehistoric stone circle at Avebury in Wiltshire
10/12 Byzantine mosaic, discovered in February 2007
Plans for a walkway at the centre of the furious dispute over Jerusalem's holiest site were delayed by the discovery of a Byzantine mosaic
11/12 Ancient gold, discovered in March 2014
Gold fitting for a dagger sheath (around 1900 BC.) found near Stonehenge
12/12 Rosetta Stone, discovered in 1799
The Rosetta Stone is a basalt slab inscribed with a decree of pharaoh Ptolemy Epiphanes (205-180 BC) in three languages, Greek, Hieroglyphic and Demotic script. Discovered near Rosetta in Egypt
Stein said there was evidence of wheat and barley farming in the town where the skeletons were found and that irrigation might have also spurred outbreaks of other diseases like malaria by creating pools of stagnant water for mosquitoes to breed.
Piers Mitchell, another study author, said ancient farming societies could have inadvertently launched the global transmission of the flatworm parasites, which sicken millions of people every year. He said modern irrigation systems are still spreading diseases in developing countries.
“In many parts of Africa, someone clever decides to put in a dam or an artificial water source and then 10 years later, everyone's getting schistosomiasis,” Mitchell said.
The research was published online Thursday in the journal Lancet Infectious Diseases.
Other experts agreed it was likely that irrigation spread parasitic diseases beginning in ancient times.
“Egypt along the Nile was a hotspot for generations because people were crammed into the flood plain and there were probably a lot of people who had low-level (flatworm) infections for their entire lives,” said Quentin Bickle, a parasite expert at the London School of Hygiene and Tropical Medicine. “People would have known there was something weird going on but they wouldn't have known what to do about it.”