CURRENT STATE AND FUTURE-TRENDS IN THE DIAGNOSIS OF BABESIOSIS

An overview is given of the currently available methods to diagnose ba besiosis in livestock. Microscopic techniques are still the only appro priate techniques to diagnose acute disease. Thin or thick blood films stained with Giemsa's stain are sufficient. The sensitivity ranges fr om 10(-5) to 10(-6), i.e. one parasite per 10(5)-10(6) erythrocytes ca n be detected. Thick films stained with acridine orange (sensitivity a pproximately 10(-7)) and the Quantitative Puffy Coat (QBC) analysis tu be system (sensitivity approximately 10(-7)-10(-8)) are applicable for diagnosis in the laboratory. DNA probes are very specific tools to id entify haemoparasites in organs post mortem and in ticks. For the iden tification of carrier animals the sensitivity (approximately 10(-5)-10 (-6)) is generally not sufficient. For the latter the polymerase chain reaction (PCR) technique is a very powerful tool (sensitivity approxi mately 10(-9)). Many different serodiagnostic tests have been describe d; however, the immunofluorescence antibody test is the most widely us ed, while the enzyme-linked immunosorbent assay (ELISA) is the test sy stem which holds the greatest promise for the future. Thus far, improv ements to the ELISA have been limited as the quality of antigen prepar ations made from infected blood is generally poor with a few exception s (Babesia bovis, Babesia caballi). Potentially, most of the problems associated with crude antigens can be overcome by the production of re combinant antigens. Several ELISAs based on highly defined recombinant antigens have been described and show promise. None of these tests ha s been validated to the extent that it could be applied globally. Futu re research requirements as well as the need for coordination of the r esearch effort and collaboration between institutions involved in the diagnosis of babesiosis are discussed.