Liver histopathology and an in-house indirect ELISA method for the diagnosis of bovine fasciolosis

Abstract

Tropical fasciolosis is regarded as one of the most important helminth infections of ruminants in Asia and Africa. Throughout most of its geographical range, Fasciola gigantica is of great importance as a parasite in cattle and buffalo. Fasciolosis diagnosis, due to low sensitivity of the coprological diagnostic method has been challenging for a long period. In this study, an in-house indirect enzyme-linked immunosorbent assay (iELISA) method; one of the most sensitive tests in this regard, using excretion–secretory (ES Ag) and Crude (Cr Ag) antigens and liver histopathology of F. gigantica were described for diagnosis of fasciolosis in cattle. For this purpose, the sera and liver specimens of slaughtered cattle were collected and their liver examined macroscopically and microscopically for infestation to fasciolosis. Sera from two groups of cattle, one infected with fasciolosis (n = 50) and the other non-infected with fasciolosis (n = 50), were used in the iELISA test; grouping based on histopathology results. All sera were tested by an in-house iELISA using optimum concentration of antigens. The sensitivity, specificity, accuracy, positive and negative predictive values of iELISA with ES Ag was 88%, 80%, 85%, 81%, and 87%, respectively, and with Cr Ag was 90%, 74%, 82%, 76%, and 88%, respectively. In conclusion, there was a good correlation between these two diagnostic tests of fasciolosis although iELISA using ES Ag was more closely correlated with the histopathology findings and could be regarded as a rapid diagnostic method in bovine fasciolosis.