**Abstract**

Many diseases linked with trematodes are zoonotic, including liver flukes (*Fasciola* spp., *Clonorchis*, and *Opistorchis* are the most common), intestinal flukes (some species of the Heterophyidae), lung flukes (*Paragonimus* spp.) and the blood flukes (schistosome species). A characteristic for all these species is that they have a vertebrate as final host and have freshwater snail species as the first intermediate host, and for the food-borne trematodes, also a second intermediate host where their infective stage (metacercariae) lodge or in case of the Fasciolidae, cercariae encyst on aquatic or semi-aquatic plants. We describe the biology of transmission with emphasis on the intermediate snail hosts, and the control of these.

**Keywords:** schistosomiasis, liver flukes, intestinal flukes, snail intermediate host
