Schistosomiasis, a parasitic disease that used to be the leading cause of liver cirrhosis in Egypt before being superseded by hepatitis C, has been plaguing Nile-dwellers for a long long time, according to evidence from recently discovered mummies.

Schistosomiasis, also known as bilharziasis, is caused by an infectious worm that lives part of its lifecycle within freshwater snails. These snails prefer stagnant water and are quickly washed away in flowing water. That is why bilharziasis is much more prominent in irrigation canals, which are a perfect habitat for the snail hosts before they infect humans through their skins.

According to ScienceOnline, anthropologists analyzed tissues from two sets of Nubian mummies excavated at the border between Egypt and Sudan. One group used the flowing and flooding waters of the Nile to irrigate their land while the other one dug canals and relied on artificial irrigation to grow their crops.

The mummies from the community that dug these canals were found to have 25% higher parasitic load than the group that irrigated off the Nile waters directly. This reflects a pattern that is similar to the same situation of many Nile-dwelling farmers in Africa now.

Schistosomiasis started to rapidly spread in North Africa in the 1950’s following the construction of large dams and irrigation projects to feed growing populations and to increase fertile lands. The rapid rise of infections with the worm causing the disease can be correlated to the spread of these projects.