Parasitic diseases are huge problem for human and veterinary medicine and for economy, agriculture and wildlife management. One of these diseases is fasciolosis, which is caused by two trematode species, Fasciola hepatica (liver fluke) and Fasciola gigantica. Only F. hepatica is a concern in Europe and Americas but the distribution of both species overlaps in many areas of Africa and Asia (Mas-Coma et al., 2005). F. hepatica occurs mostly in cattle, sheep and wild ruminants. Recently, worldwide losses in animal productivity due to fasciolosis were estimated at over US$ 3.2 billion per annum (Spithill et al., 1999). The infection of humans has been regarded as accidental for many years. However, fasciolosis is now recognized as an emerging human disease: the World Health Organization (WHO, 2006) has estimated that 2.4 million people are infected with F. hepatica and a further 180 million are at risk of infection (Mas-Coma et al., 1999).