Tehran University of Medical Sciences Iranian Journal of Parasitology 1735-7020 9 3 2014 09 15 374 381 EN Said Ibrahim Shalaby Department of Complementary Medicine, Medical Division, National Research Centre, Cairo, Egypt. Mohammad El-Bahy Department of Parasitology, Faculty of Veterinary Medicine, Cairo University, Cairo, Egypt. Samy Ibrahim Aboulella Shalaby Department of Reproduction, Veterinary Division, National Research Centre, Cairo, Egypt. Hatem Shalaby Department of Parasitology, Veterinary Division, National Research Centre, Cairo, Egypt. Neelima Gupta Department of Animal Science, MJP Rohilkhand University, Bareilly, UP, India. Dileep Kumar Gupta Department of Zoology, Bareilly College, Bareilly, UP, India. 2015 10 14 Background:The study was targeted to report the appearance of coproantigens in feces and circulating antibodies in the serum of Fasciola gigantica  experimentally infected rabbits. Methods: Copro Hyper Immune Serum (HIS) and Excretory-Secretory Hyper Immune Serum (ES HIS) antigens were used in a sandwich ELISA for the detection of F. gigantica antigens in feces of 12 rabbits experimentally infected with different doses of F. gigantica encysted metacercariae (EMC) (10, 25 and 30 EMC). The relation between time of appearance of coproantigens in feces and anti-Fasciola antibodies in serum was evaluated. Results: The earliest diagnostic coproantigen was recorded at 21st, 25th and 28th day post-infection (p.i.) in groups of rabbits infected with 30, 25 and 10 F. gigantica EMC respectively. Both HIS and ES HIS were able to detect coproantigens in feces of rabbits infected with 30 EMC at day 21 p.i. The appearance of F. gigantica coproantigens in feces of infected rabbits was concurrent to the appearance of anti-Fasciola antibodies in blood (3rd week p.i.).However, coproantigen has specific ability for direct assessment of active infection with minimal cross-reaction with other heterologous parasitic infections. Conclusion: The findings hold promise for a more accurate diagnostic technique in the near future for suspected Fasciola infection.   https://ijpa.tums.ac.ir/index.php/ijpa/article/view/389 https://ijpa.tums.ac.ir/index.php/ijpa/article/download/389/355