Early detection of Fasciola gigantica infection in buffaloes by enzyme-linked immunosorbent assay and dot enzyme-linked immunosorbent assay.

In an attempt to develop a suitable serological test for early detection of Fasciola gigantica infection in buffaloes, a group of proteins were isolated from the somatic antigen of the parasite by immunoaffinity chromatography. The process of isolation of the proteins has been standardized and significant level of repeatability was achieved. To test the diagnostic potentiality of the antigens, two serological tests, viz., enzyme-linked immunosorbent assay (ELISA) and dot enzyme-linked immunosorbent assay, were standardized using the sera from experimentally noninfected (group A) and infected (group B) animals. Further, the sensitivity and the specificity of the tests were evaluated employing the field sera from animals of different parasitic load viz., F. gigantica positive (group C), F. gigantica and Gastrothylax crumenifer positive (group D), F. gigantica and Gigantocotyle explanatum positive (group E), a group of sera without F. gigantica but other trematode infection (group F), only G. crumenifer positive (group G), only G. explanatum positive (group H), G. crumenifer and G. explanatum positive (group I), and PM negative (group J) collected from slaughterhouses of Bareilly (Uttar Pradesh, India) and Patna (Bihar, India). In plate ELISA, the sensitivity of the antigen and the test was 75.75% while the specificity was 97%, 95%, and 98%, respectively, against G. crumenifer, G. explanatum, and mixed infection of G. crumenifer and G. explanatum, respectively. In the case of dot ELISA the sensitivity was 86.5% and specificity was 92.3%, 94.7%, and 90%, respectively, against G. crumenifer, G. explanatum, and mixed infection of G. crumenifer and G. explanatum, respectively. The potentiality of the antigen in the diagnosis of field infection is discussed.