Contribution to the serological diagnosis of sarcocystosis.

The importance of the IFA-test (Indirect Fluorescent Antibody Test) in the diagnosis of sarcocystosis in the intermediate host has been confirmed in the present paper. We assessed the time of the first appearance of serum antibodies in the intermediate host in mice inoculated experimentally with the species Sarcocystis dispersa. By means of the IFA-test, the first antibodies were found on day 20 p.i. Cross-reactions among antisera of S. dispersa and a heterologous antigen of S. cernae disclosed that the reaction was not species-specific, but genus-specific. In addition, we confirmed serologically that the antigenic structure of the genus Frenkelia was identical to that of the genus Sarcocystis, because the results of cross reactions obtained with the IFA-test were identical.