Clonorchis sinensis, Opisthorchis felineus and Opisthorchis viverrini are the three most important liver flukes
involved in human health, infecting more than 45 million people worldwide. Both C. sinensis and O. viverrini,
and possibly O. felineus, can induce human cholangiocarcinoma as well as inducing other hepatobiliary
pathology. Although the life cycles of all three species are similar, only that of O. felineus in Europe
remains predominantly zoonotic, while O. felineus in Asia and C. sinensis have a stronger mixture of zoonotic
and anthroponotic components in their life cycles. Opisthorchis viverrini from the Mekong area of
southeastern Asia is predominantly anthroponotic. Here we discuss the comparative epidemiology of
these three taxa comparing in detail the use of first, second and final animal hosts, and consider the
potential role of humans in spreading these pathogens. In addition we discuss the genetic structure of
all three species in relation to potentially cryptic species complexes