Abstract
Background Gold standard microscopic examination of P. falciparum intraerythrocytic stage remains an important process for staging and enumerating parasitized erythrocytes in culture; however, microscopy is laborious, and its accuracy is dependent upon the skill of the examiner.Methods In this study, we used ViSafe Green (VSG), which is a nucleic acid-binding fluorescent dye, to assess in vitro development of P. falciparum using flow cytometry.Results Fluorescence intensity of VSG was found to depend on the developmental stage of parasites. Specifically, multiple-nuclei-containing schizonts were observed in the VSG high population, and growing trophozoites and ring-shaped forms were observed in the VSG intermediate and VSG low populations. The VSG-based assay was found to be comparable to the microscopic examination method, and capable of detecting as few as 0.001% of the parasitemia estimated by Giemsa staining. Moreover, when applying VSG for antimalarial drug test, we were able to observe the growth inhibitory effect of dihydroartemisinin, the front-line drug for malaria therapy.Conclusions Taken together, the results of this study suggest the VSG-based flow cytometric assay to be a simple and reliable assay for assessing P. falciparum malaria development in vitro .