rRNA-based method for sensitive detection of Babesia bigemina in bovine blood.

Three synthetic oligonucleotide probes complementary to unique regions of Babesia bigemina small-subunit rRNA were developed for detecting the parasite in bovine blood. These probes specifically detected a parasitemia of 2 x 10(-5)% by autoradiography in less than 24 h by using a 200-microliters sample of bovine blood. These probes did not bind to total RNA or genomic DNA isolated from another closely related species, Babesia bovis, or to bovine leukocyte RNA. This method detected B. bigemina infections in calves inoculated with as few as 1,000 infected erythrocytes from the second day onward for 16 days.