Common antigens of Fasciola gigantica, Dicrocoelium hospes and Schistosoma bovis and their relevance to serology

The possession of common antigens by three trematode parasites which commonly occur together in ruminants in the tropics, Fasciola gigantica, Dicrocoelium hospes and Schistosoma bovis was studied in relation to the reliability of serodiagnosis of infection with these helminths. The crude antigenic extracts of the three trematodes were subjected to Sephacryl S-300 column chromatography and F. gigantica was fractionated into six peaks, S. bovis into nine peaks and D. hospes into seven peaks. Common antigens were found in these three trematodes in both the crude whole worm antigenic extracts and in the semi-purified fractions obtained by Sephacryl S-300 column chromatography. The implications of this finding and the limitation it imposes on the usefulness of serodiagnostic tests in routine use as regards their specificity are discussed in relation to previous studies.