Performance characteristics of an enzyme-linked immunosorbent assay for the detection of liver fluke (Fasciola hepatica) infection in sheep and cattle

AIM: To validate an enzyme-linked immunosorbent assay (ELISA) for the detection of antibodies against liver fluke (Fasciola hepatica) in sheep and cattle sera. METHODS: Gold-standard sera from sheep and cattle of known infection status, i.e. sera from non-infected animals and from animals known to be infected with F. hepatica were assayed with a commercially available ELISA and results analysed by ROC analysis. RESULTS: The ROC analysis suggested cut-offs that were considerably lower than those suggested by the manufacturer, yet the ELISA performed with high sensitivity and specificity, 98 to 100%, respectively for sheep and cattle sera. For bovine sera, particularly good discrimination between positive and negative sera was observed. Infection in experimentally infested animals could be demonstrated 7-8 weeks earlier than with classical parasitological techniques. CONCLUSIONS: The analysis of the ELISA's performance demonstrated high sensitivity and specificity. ROC analyses optimised the cut-off point suggested by the manufacturer of the commercial diagnostic assay. Diagnosis of infection with F. hepatica was achieved much earlier than is possible with current parasitological techniques. This could help with the control of fasciolosis, enabling treatment before clinical manifestation of the disease.