MM3-ELISA evaluation of coproantigen release and serum antibody production in sheep experimentally infected with Fasciola hepatica and F-gigantica

During an experimental infection of sheep with Fasciola hepatica of F. gigantica, MM3-SERO and MM3-COPRO ELISA tests were applied to compare the kinetics of antibody production and coproantigen release between the 2nd and 32nd week post-infection (wpi). The Kato-Katz technique was used to measure the kinetics of egg shedding by both Fasciola species (eggs per grain of feces, epg). The kinetics of IgG antibodies for all sheep infected with F. hepatica and F gigantica followed a similar pattern. Optical density (OD) increased rapidly between the 4th until the 12th wpi, when the highest Values were reached and then decreased slowly until the 32nd wpi. Coproantigen levels increased above the cut-off-value between 6 and 9 wpi in the F. hepatica group, and between 9 and 11 wpi in the F gigantica group. The comparison between coproantigen levels and epg indicated that F. hepatica infected sheep had detectable amounts Of coproantigens 4-7 weeks before patency (egg shedding), while F.gigantica-infected sheep had detectable amounts of coproantigens 3-6 weeks before patency. When comparing the kinetics of coproantigen release vs the kinetics of epg, a similar pattern emerged, but With a two-week time-lag in epg, for both F. hepatica and F. gigantica infections. The amount of coproantigen release by each adult was not burden dependent for F hepatica infection (burden of 33-66 adults), while it was for F. gigantica infection (burden of 17-69 adults). The results demonstrate the usefulness of the MM3-SERO and MM3-COPRO ELISAs as tools for the diagnosis of early as well as long-term fascioliasis infections, and suggest that they call potentially be applied to human fascioliasis even ill Countries where F. hepatica and F gigantica co-exist. These tests can be employed not only in the diagnosis, but also in studies oil epidemiology as well as pathogenesis and treatment in animals and humans since they allow post-treatment infection monitoring. (c) 2008 Elsevier B.V. All rights reserved.