Scientists have discovered the earliest known evidence of infection with a parasitic worm, that now afflicts more than 200 million people worldwide, in a skeleton over 6,200 years old.
The discovery of a schistosomiasis parasite egg in a grave at a prehistoric town by the Euphrates river in Syria may be the first evidence that agricultural irrigation systems in the Middle East contributed to disease burden, according to the study published in The Lancet Infectious Diseases.
Schistosomiasis is a disease caused by several species of flatworm parasites that live in the blood vessels of the bladder and intestines. Infection can result in anaemia, kidney failure, and bladder cancer.
The research by an international team shows it may have been spread by the introduction of crop irrigation in ancient Mesopotamia, the region along the Tigris-Euphrates river system that covers parts of modern-day Iraq, Iran, Kuwait, Syria, and Turkey.
According to one of the authors Dr Piers Mitchell, at the University of Cambridge, UK, the discovery might be among the oldest evidence of human-made technology inadvertently causing disease outbreaks.
"The individual who contracted the parasite might have done so through the use of irrigation systems that were starting to be introduced in Mesopotamia around 7,500 years ago," Mitchell said.
"The parasite spends part of its life cycle in snails that live in warm fresh water, before leaving the snail to burrow through the skin of people wading or swimming in the water.
"These irrigation systems distributed water to crops and may have triggered the beginning of the enormous disease burden that schistosomiasis has caused over the past 6,000 years," said Mitchell.
The finding shows that the parasite infected humans at least a thousand years earlier than has been found in Egypt. The oldest Schistosomiasis egg found previously was in Egyptian mummies from 5,200 years ago.
The egg was found in the pelvic area of the burial where the intestines and bladder would have been during life.
Control soil samples from the head and foot areas of the grave contained no parasitic eggs, suggesting that the grave-site was not contaminated with the parasite more recently.
Schistosomiasis has become progressively more common over time so that it causes a huge burden across the world today, with over 200 million people infected.
