Prepatent detection of <i style="">Fasciola gigantica</i> infection in bovine calves using metacercarial antigen

Abstract

Metacercarial antigen of <i style="">Fasciola gigantica</i> was evaluated for early immunodiagnosis of experimental bovine fasciolosis using ELISA and Western blot. In ELISA, the experimental <i style="">F. gigantica</i> infection was detected as early as 2 weeks post-infection (WPI). The gradual increasing trend of antibody level was observed from 2 to 7 WPI, followed by a plateau, which was maintained up to 14 WPI. In Western blot, sera from experimentally infected calves recognized one distinct polypeptide of 21 kDa in fractionated metacercarial antigen as early as 10 ^thday post infection. From 2 WPI, more polypeptide bands were reacting. Recognition of these protein bands persisted till the end of the experiment (14 WPI). Cattle sera collected from the field showed 34.5% seroprevalence of fasciolosis by ELISA using MAg. Comparative immunoblot studies of metacercarial antigen with anti-<i style="">Gigantocotyle explanatum </i>and<i style=""> </i>anti<i style="">-Paramphistomum epiclitum </i>sera revealed that 21 and 25 kDa polypeptides of metacercarial antigen did not cross-react with any of these sera and appear to be unique to <i style="">F. gigantica</i> and having the desirable qualities of early and specific immunodiagnosis.