Evaluation of an enzyme linked immunosorbent assay using a recombinant antigen for the diagnosis of Theileria annulata infection.

Studies of surface antigens of Theileria annulata crude piroplasms enabled to identify immunogenic proteins that could be used in diagnosis tests. The gene coding for one of these proteins has been determined and cloned. A recombinant protein was producted by molecular biology techniques and purified. An Enzyme Linked Immunosorbent Assay using this protein as antigen was developed and standardised and evaluated with 261 bovine control sera infected with T. annulata and negative controls. High titres anti T annulata antibodies were detected in the sera of animals infected with T annulata whereas they were very low in the negative control sera. The specificity and sensitivity of this test were estimated and were 0.96 and 0.89 respectively whereas they were 0.97 and 0.75 respectively for ELISA test using the crude piroplasme as antigen. Correlation between these ELISA tests was calculated and the kappa value was 0.62. These preleminary investigations showed that this assay could be used as a screening test in epidemiological studies of tropical theileriosis in Morocco.