Bilharzia is a freshwater parasite that causes the disease schistosomiasis, an infection which impacts the liver, kidneys, bladder, rectum, and can lead to death. The vector for the parasite is freshwater snails, which thrive in the standing water that fill Egypt’s irrigation canals. Rates of bladder cancer—the most common form of cancer in Egypt—are directly tied to rates of bilharzia.
Sources:
Shady Salem, et al. “Successful control of schistosomiasis and the changing epidemiology of bladder cancer in Egypt,” BJU International, May 7, 2010, accessed October 24, 2013.