Piers Mitchell, a biological anthropologist from the University of Cambridge in the UK, and colleagues discovered a schistosomiasis parasite egg in an ancient grave in Tell Zeidan, Syria, which could be the earliest evidence that show man-made technology, may be partly responsible for the spread of the disease, which currently afflicts about 240 million people worldwide.
Schistosomiasis, also known as snail fever, is caused by the parasitic flatworm known as schistosoma, or blood flukes, that live in certain types of freshwater snails and infect the urinary tract or intestines. For the study published in the Lancet Infectious Diseases journal on June 20, the Mitchell and colleagues excavated 26 human skeletal remains from a 6,200-year-old grave in Tell Zeidan in Northern Syria which used to be an early settlement of farmers.
The researchers also collected sediments from the area where the intestines and bladder of the excavated skeletons were when they were still alive and where the schistosoma parasite could be found. After sifting through the sediments, the researchers found one egg in a soil around a child's pelvic area.
"One individual had evidence for infection with a terminal spined schistosome," the researchers wrote. "The egg discovered in the pelvic sediment had a curved pole, a terminal spine at the opposite pole, a single wall, pale brown coloring, and measured 132×56 μm."
The researchers said that the egg could serve as evidence that the ancient irrigation systems employed in the Middle East was partly responsible for the spread of schistosomiasis as remnants of wheat and barley found at the site suggest of an irrigation system at Tell Zeidan centuries ago. The farmers could have waded in freshwater that were perfect breeding grounds for snails that host the schistosomiasis parasite to do weeding and planting.
"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 7500 years ago," Mitchell said. "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 6000 years."
Although the parasite responsible for schistosomiasis is not present in the U.S., the disease is considered the most devastating parasitic disease worldwide, second only to mosquito-borne malaria. The disease, which can be caught through contact with contaminated water, could lead to serious damage including infertility problems, liver damage and bladder cancer as well as growth and learning problems in children.
