“…The high rate of heavy infection in coastal plain terrain (36.1%, Table 2 ) may indicate the recent expansion of infection in coastal plain terrain. Several risk factors may explain the high prevalence of fascioliasis in the coastal plains of TTH province, Vietnam; the expansion of dams for blocking brackish water entry to the field for agricultural production and irrigation systems for supplying fresh water [ 9 , 10 , 11 , 12 , 18 , 30 , 31 , 37 , 38 , 39 , 40 , 41 ], leading to the enlargement of field for cultivation and cattle raising, may enlarge the habitable area for intermediate host snails [ 4 , 45 ], as is shown in bilharziasis [ 25 ], and enhance snail migration and/or the presence of Fasciola parasite eggs. Floods during the rainy season may also contribute to the dissemination of snails and Fasciola eggs to the coastal terrain.…”