DISCRIMINATION BETWEEN 6 SPECIES OF THEILERIA USING OLIGONUCLEOTIDE PROBES WHICH DETECT SMALL-SUBUNIT RIBOSOMAL-RNA SEQUENCES

The complete small subunit ribosomal RNA (srRNA) gene of Theileria par va was cloned and sequenced. Two primers were designed which permitted the specific amplification of part of the Theileria srRNA gene from T heileria-infected cell line samples which were predominantly (> 95 %) bovine DNA. The sequence of the central (variable) region of the srRNA genes of T. annulata, T. taurotragi, T. mutans and two unidentified p arasites referred to as Theileria sp. (buffalo) and Theileria sp. (Mar ula) were obtained. An alignment of the sequences was generated from w hich 6 oligonucleotide probes, corresponding to species-specific regio ns, were designed. These probes were demonstrated to provide unequivoc al identification of each of the 6 species either by direct detection of parasite srRNA or by hybridization to amplified parasite srRNA gene s. The probes were not able to distinguish buffalo-derived T. parva, t he causal agent of Corridor disease, from cattle-derived T. parva, the causal agent of East Coast fever.