Detection of extracellular forms of babesia in the blood by electron microscopy: a diagnostic method for differentiation from Plasmodium falciparum

Light microscopic examination of blood smears is the traditional approach for the diagnosis of babesiosis, but there is morphological overlap with Plasmodium falciparum . The authors describe 3 patients with babesial infection in whom the diagnosis was made by identifying extracellular merozoites in a buffy coat preparation using electron microscopy. This method resulted in a high yield of extracellular babesia, even in a case where virtually no extracellular babesia were detectable in the blood smear. The test had a reasonably fast turnaround time and allowed detailed visualization of the organisms and reliable distinction from Plasmodium falciparum .