How can environmental changes such as irrigation projects increase schistosomiasis?

Environmental changes such as irrigation projects significantly increase the risk of schistosomiasis by altering local ecosystems to favor the survival and proliferation of the disease's intermediate hosts: snails.12

The transmission cycle of the parasitic flatworms responsible for the disease relies on fresh water. When irrigation infrastructure is introduced, it creates new, stable bodies of water—such as canals and reservoirs—that provide ideal habitats for these snails to thrive. Because schistosomiasis is typically contracted through contact with water populated by these infected snails, the expansion of irrigation networks increases the frequency of human interaction with contaminated water sources.1

This environmental modification often occurs in rural areas where infrastructure for sanitation and hygiene may be limited, further facilitating the spread of the parasite among populations that rely on these water sources for daily activities like working, bathing, or swimming. Consequently, while irrigation is vital for agriculture, it necessitates integrated public health strategies, such as improved water management and vector control, to mitigate the heightened risk of infection.12