Evaluation of Fasciola somatic antigenic fractions in the diagnosis of human fascioliasis.

Fasciola somatic antigen was fractionated by column chromatography. Four peaks were obtained. They were evaluated separately using IgG and IgM ELISA in the diagnosis of fascioliasis. Patients were diagnosed through a survey in Abis 13/4 Village depending on stool examination, clinical, haematological findings and on the results of IHAT. Sera were obtained from cases of confirmed fascioliasis, acute fascioliasis, schistosomiasis and from parasite free healthy individuals. After establishing the optimal conditions for the test, ELISA was performed using all fraction and all sera. The results were then computerized and specificity, sensitivity, accuracy, positive predictive value (PPV), negative predictive value (NPV), and probability of disease when test is positive (PDP) were determined at different cut off levels. These parameters were calculated using both sera of normal cases and of S. mansoni infected cases as controls. It was concluded that fraction I in IgG ELISA was the best for diagnosis of chronic cases. Fraction I by IgM was the best for acute infection. Results of the latter antigen/system combination were not decreased when S. mansoni sera were used as control.