PIROPLASMS OF DOMESTIC-ANIMALS IN THE MACEDONIA REGION OF GREECE .1. SEROLOGICAL CROSS-REACTIONS

During a serological survey on haemoparasites in Macedonia, serum samp les were collected from cattle, sheep and goats. All sera were tested by the indirect immunofluorescence test (IFAT); the cattle sera agains t Theileria orientalis, T. annulata, Babesia bigemina, B. bovis, B. di vergens and B. major antigens; the sheep and goat sera against T. ovis , B. ovis, B. motasi and B. crassa antigens. Parallel tests of negativ e and positive control sera against all the antigens showed the existe nce of cross-reactions of different degrees between species of the sam e genus. In cattle, the most important cross-reactions were obtained a gainst B. bigemina antigen, especially with the anti-B. bovis serum, i n small ruminants against B, motasi with the anti-B. crassa serum. In the field sera, there was a high correlation between the antibody titr es of B. bigemina and B. bovis, and also between the titres of these t wo Babesia spp. and B. divergens. A high correlation was also found be tween B. motasi and B. crassa, and lower ones between these two and B. ovis. The correlations of the sera titres were due to mixed infection s or to cross-reactions. Therefore, the use of the IFAT is not always satisfactory for diagnosing infections in regions where animals are in fected With different piroplasms.