Theileria annulata: genetic characterization of Spanish isolates by isoenzyme electrophoresis and random amplified polymorphic DNA.

Isoenzyme electrophoresis and RAPD techniques were used to study the genetic polymorphism of different Spanish isolates of Theileria annulata in the schizont and piroplasm stages. Enzyme activity attributable to the parasite was detected in only 5 of the 13 loci studied with isoenzyme electrophoresis. Of these, differences between the cell lines studied were found only in the loci GPI, ICD, and FH. Only 6 of the 11 primers used in the RAPD generated reproducible genomic DNA fingerprints. None of the amplification products generated using primers ILO 509, ILO 525, ILO 872, and ILO 875 hybridized with DNA of the bovine cell line not infected by T. annulata, BL20, indicating that this technique can be used with either piroplasm DNA or DNA from parasite schizonts after first passing it through DEAE cellulose columns. The results obtained with both characterization techniques demonstrate a moderate degree of polymorphism among the Spanish isolates of this protozoan.