Plasmodium falciparum parasites exit the infected erythrocyte after haemolysis with saponin and streptolysin O

Automated Recognition of Plasmodium falciparum Parasites from Portable Blood Levitation Imaging

In many malaria-endemic regions, current detection tools are inadequate in diagnostic accuracy and accessibility. To meet the need for direct, phenotypic, and automated malaria parasite detection in field settings, a portable platform to process, image, and analyze whole blood to detect Plasmodium falciparum parasites, is developed. The liberated parasites from lysed red blood cells suspended in a magnetic field are accurately detected using this cellphone-interfaced, battery-operated imaging platform. A validation study is conducted at Ugandan clinics, processing 45 malaria-negative and 36 malaria-positive clinical samples without external infrastructure. Texture and morphology features are extracted from the sample images, and a random forest classifier is trained to assess infection status, achieving 100% sensitivity and 91% specificity against gold-standard measurements (microscopy and polymerase chain reaction), and limit of detection of 31 parasites per µL. This rapid and user-friendly platform enables portable parasite detection and can support malaria diagnostics, surveillance, and research in resource-constrained environments.

Visualization of Infected Red Blood Cell Surface Antigens by Fluorescence Microscopy

Immunofluorescence labeling enables the detection and characterization of various parasite proteins presented on the surface of the infected red blood cell. Several approaches for immunofluorescence detection of red blood cell surface-presented proteins of Plasmodium spp. have been successfully established and published over the years. However, finding the right approach depends on the scientific question, and different protocols have different advantages. Here, we discuss some aspects that should be considered and present an easily applicable protocol for labeling parasite surface antigens, which subsequently can be analyzed by immunofluorescence microscopy (or flow cytometry).