Ancient parasite highlights humans’ role in spread of disease

The discovery of a schistosomiasis parasite egg in a 6,200-year-old grave in Syria may be the earliest evidence that agricultural irrigation systems in the Middle East contributed to a vast spread of disease, scientists said. Schistosomiasis – also known as bilharzia, snail fever, or Katayama fever – is caused by flatworm parasites that live in the blood vessels of the bladder and intestines. The infection can lead to anaemia, kidney failure and bladder cancer. In a study in the Lancet Infectious Diseases journal, researchers said 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 what is Iraq, Iran, Kuwait, Syria and Turkey. The infection, in which the parasite burrows through the skin of people wading or swimming in waters where it hides in freshwater snails, has become progressively more common over time and now causes a huge...