Figure 3
From: The roles of water, sanitation and hygiene in reducing schistosomiasis: a review
Flow diagram demonstrating how sanitation may increase or decrease snail numbers, depending on the organic pollution of the water. By containing excreta, and keeping it away from water bodies, sanitation will reduce organic pollution. However, this may be either detrimental, or under certain circumstances, beneficial to intermediate host snails, that thrive under conditions of mild (but not low or high) organic pollution.