Each year, two hundred eighty thousand people die of schistosomiasis, also known as bilharzia or snail fever. The microscopic worms infect snails, which in turn lay infected eggs.

• 每年有280000人因为血吸虫导致的血吸虫病和钉螺热而死亡。显微镜下血吸虫感染钉螺，然后开始产卵。