Role of Fast-ELISA and Western Blot in Diagnosis of Human Fascioliasis Using Crude Adult Worm and Excretory/Secretory Fasciola Antigens

Background: Human fascioliasis is becoming one of the public health problems in Egypt. Because of the similarity of fascioliasis manifestations and other hepatobiliary diseases, the clinical diagnosis of this disease is usually difficult. Objective: Diagnosis of human fascioliasis using different worm antigens [crude worm antigen (CW) and excretory/secretory antigen (E/S)] and different methods [Falcon assay screening test enzyme linked immunosorbent assay (FAST-ELISA) and immnoelectrotransfer blot (Western Blot)]. The second objective is to compare between FAST-ELISA and Western Blot using the same antigen, also to compare between the use of (CW) antigen and (E/S) antigen in each method aiming to evaluate the immunodiagnostic potential of both techniques and both antigens. The third objective is to detect the most specific and sensitive immunoreactive bands in both CW and E/S Fasciola antigens by western blot technique. Material and Methods: One hundred and fifteen individuals (40 with chronic fascioliasis, 15 with suspected acute fascioliasis, 40 infected with other parasites and 20 apparently healthy) were included in this study. Sera, urine samples and repeated stool samples were collected from all cases. The stool samples were examined for presence of different parasites and Fasciola eggs were counted by Kato-Katz technique. Fasciola (CW) and (E/S) antigens were prepared. Sera were tested by (FAST-ELISA) and (Western Blot) techniques using (CW) and (E/S) antigens. Results: FAST-ELISA using (E/S) gave better results than that using CW antigen, as the recorded sensitivities and specificities were 97.5% and 98.3% with E/S antigen and 92.5% and 86.7% with crude antigen respectively. By using each of CW antigen and E/S antigen, Western blot was more sensitive and specific than FAST-ELISA in diagnosis of human fascioliasis. After fractionation of both antigens by electrophoresis and immunoblotting, it was found that 27 KDa of Fasciola E/S antigen was the best fraction (100% sensitive and specific). Conclusion: Immnoelectrotransfer blot (western blot) is more sensitive and specific than FAST-ELISA. In immnoelectrotransfer blot, 27 KDa of E/S antigen was the most specific, sensitive and accurate band that could detect Fasciola antibodies in all Fasciola infected patients.