Molecular and immunological characterisation of Fasciola species

Fasciola hepatica and F. gigantica are polymorphic liver flukes that show considerable overlap between species, and various protein separation techniques have been used as alternative means of differentiation. Acid and alkaline polyacrylamide gel electrophoresis (PAGE) show differences between F. hepatica and F. gigantica. Following SDS-PAGE, F. hepatica proteins are characterised by the presence of eight major peptide bands, with molecular weights estimated as 48, 45, 43.5, 37, 33, 29, 27 and 25.5 kDa. In contrast, F. gigantica shows only five major protein bands of 57.6, 54, 48, 29 and 27 kDa. Isoelectric focusing (IEF) demonstrates 17 bands from F. hepatica and 22 bands from F. gigantica between pH 3.5 and pH 10. Although many bands appear common to both species, some are species-specific. Six cases of human acute fascioliasis diagnosed clinically, haematologically and immunologically are also studied. Gel immunodiffusion and immunoelectrophoresis, using adult F. hepatica and F. gigantica antigens, are used to determine the species, and indicate that the antisera are more specific for F. hepatica.