Comparison between Different Immunological Techniques for Detection of Circulating Fasciola Antigen in sheep

The detection of Fasciola antigen in serum or stool could be more valuable in diagnosis, hence early treatment before irreparable damage. In this study, fresh adult Fasciola gigantica worms were collected, then incubation in culture medium and collected medium was used to extract crude excretory-secretory (E/S) antigen. E/S was used to immunize rabbits to raise specific antibodies against Fasciola spp. Purified antibodies are further used as primary capture to coat ELISA plates. The secondary capture of antibodies was by conjugation with horse reddish peroxidase. Sandwich ELISA and DOT-ELISA were performed to detect Fasciola antigens in both serum and stool samples collected from a total of 152 sheep. After slaughtering, gross inspection of liver and parasitological stool examination, sheep were divided into Fasciola positive group (97 sheep), other helminthic infection group (30 sheep) and healthy control group (30 sheep). Fasciola antigen detected in serum of sheep by ELISA showed 94.8 % sensitivity and 95 % specificity. Copro-antigen detected by ELISA showed 96.9% sensitivity and 96.7% specificity. The sensitivity and specificity of coproantigen by ELISA in stool sample were higher than that recorded by Sandwich ELISA for serum. Dot ELISA sensitivity was found to be 98.9% and specificity 98.3%. In conclusion the Dot ELISA gives better sensitivity and specificity than sandwich ELISA for serum and coproantigen in stool by ELISA. [New York Science Journal 2010;3(7):34-39]. (ISSN: 1554-0200).