Background and Aim: Diagnosis of fascioliasis depends on clinical symptoms and routine laboratory tests. Recently, antibodies and circulating antigens of Fasciola were used for detecting active infections. Therefore, this study aimed to identify Fasciola gigantica antigens in the sera of infected cattle using Western blotting and enzyme-linked immunosorbent assay (ELISA) for an accurate diagnosis of cattle infected with F. gigantica.

Materials and Methods: Serum samples were obtained from 108, 23, and 19 cattle infected with Fasciola gigantica, Paramphistomum cervi, and Strongylids, respectively, including 57 non-infected cattle that were used as healthy cattle for the study. Western blotting and ELISA were then used to detect circulating Fasciola antigens at 27 kDa.

Results: The target epitope was detected in an F. gigantica adult-worm antigen preparation, excretory/secretory products, and serum from cattle infected with F. gigantica. However, it was absent in sera from P. cervi, Strongylids, and healthy cattle. The purified 27 kDa F. gigantica (FPA-27) antigen was also detected in cattle serum using ELISA with high degrees of sensitivity and specificity (94% and 82%, respectively), and the area under the receiver operating characteristic curve was 0.89 with a highly significant correlation of p<0.0001.

Conclusion: The FPA-27 is proposed to be a promising candidate for the serodiagnosis of fascioliasis in cattle.

Keywords: antigen, Fasciola gigantica, fascioliasis, immunodiagnostics.