In order to assess the risk of liver fluke disease on any particular farm, various environmental factors, particularly climate, landform and soil type (whether soils are heavy or free-draining) must be taken into account. This is because the intermediate host of the parasite which is a mud snail (Galba truncatula), tends to be located in soil that is slightly acidic and muddy. Thus, areas of fields with rushes or wet patches (e.g. around gates, troughs) are particularly important with regard to liver fluke risk. In addition, livestock owners should also factor in prior liver fluke history on the farm as this is an important indicator of future disease risks.