Detection of Coproantigens by Sandwich ELISA in Rabbits Ex¬perimentally Infected with Fasciola gigantica

The study was targeted to report the appearance of coproanti­gens in feces and circulating antibodies in the serum of Fasciola gigantica experi­mentally infected rabbits. 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. 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. The findings hold promise for a more accurate diagnostic tech­nique in the near future for suspected Fasciola infection.