Detection of Babesia bovis using DNA hybridization.

Plasmids containing inserts of Babesia bovis DNA were prepared and clones suitable for use in the diagnosis of B. bovis infections were isolated. Dot blot hybridization with DNA from these plasmids, which probably contain repetitive sequences, can detect after an overnight exposure 100 pg of B. bovis DNA, which corresponds to the amount of DNA present in 50 microliters of 0.01% parasitemic erythrocytes. No detectable cross-hybridization was observed with Babesia microti, Plasmodium falciparum, Plasmodium vivax, Boophilus, or cow DNA. A small amount of cross-hybridization was observed with 10 ng Babesia bigemina DNA. Use of these probes in a hybridization assay may be helpful in the diagnosis of babesiosis in cattle and ticks, in the confirmation of strain identities, and in correlating virulence with particular strains of Babesia.