Evaluation of a novel magneto-optical method for the detection of malaria parasites.
Improving the efficiency of malaria diagnosis is one of the main goals of current malaria research. We have recently developed a magneto-optical (MO) method which allows high-sensitivity detection of malaria pigment (hemozoin crystals) in blood via the magnetically induced rotational motion of the hemozoin crystals. Here, we evaluate this MO technique for the detection of Plasmodium falciparum in infected erythrocytes using in-vitro parasite cultures covering the entire intraerythrocytic life cycle. Our novel method detected parasite densities as low as ∼ 40 parasites per microliter of blood (0.0008% parasitemia) at the ring stage and less than 10 parasites/µL (0.0002% parasitemia) in the case of the later stages. These limits of detection, corresponding to approximately 20 pg/µL of hemozoin produced by the parasites, exceed that of rapid diagnostic tests and compete with the threshold achievable by light microscopic observation of blood smears. The MO diagnosis requires no special training of the operator or specific reagents for parasite detection, except for an inexpensive lysis solution to release intracellular hemozoin. The devices can be designed to a portable format for clinical and in-field tests. Besides testing its diagnostic performance, we also applied the MO technique to investigate the change in hemozoin concentration during parasite maturation. Our preliminary data indicate that this method may offer an efficient tool to determine the amount of hemozoin produced by the different parasite stages in synchronized cultures. Hence, it could eventually be used for testing the susceptibility of parasites to antimalarial drugs.
Department of Physics, Budapest University of Technology and Economics, Budapest, Hungary.
Agnes
A
Orbán
Department of Physics, Budapest University of Technology and Economics, Budapest, Hungary.
Ádám
Á
Butykai
Department of Physics, Budapest University of Technology and Economics, Budapest, Hungary.
András
A
Molnár
Department of Physics, Budapest University of Technology and Economics, Budapest, Hungary.
Zsófia
Z
Pröhle
Department of Physics, Budapest University of Technology and Economics, Budapest, Hungary.
Gergö
G
Fülöp
Department of Oral Biology, Semmelweis University, Budapest, Hungary.
Tivadar
T
Zelles
Infection and Immunity Division, Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia.
Wasan
W
Forsyth
Infection and Immunity Division, Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia; Department of Medical Biology, University of Melbourne, Parkville, Victoria, Australia.
Danika
D
Hill
Infection and Immunity Division, Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia.
Ivo
I
Müller
Infection and Immunity Division, Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia; Queensland Tropical Health Alliance Australian Institute of Tropical Health and Medicine James Cook University, Douglas, Queensland, Australia.
Louis
L
Schofield
Instituto de Medicina Molecular, Faculdade de Medicina, Lisbon, Portugal.
Maria
M
Rebelo
Instituto de Medicina Molecular, Faculdade de Medicina, Lisbon, Portugal.
Thomas
T
Hänscheid
Infection and Immunity Division, Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia.
Stephan
S
Karl
Department of Physics, Budapest University of Technology and Economics, Budapest, Hungary; Condensed Matter Research Group of the Hungarian Academy of Sciences, Budapest, Hungary.
István
I
Kézsmárki
D015415:Biomarkers / Q000032:analysis; D006420:Hemeproteins / Q000032:analysis; D006801:Humans; D008288:Malaria / Q000175:diagnosis* / Q000469:parasitology; D010963:Plasmodium falciparum; D012680:Sensitivity and Specificity
D015415:Biomarkers; D006420:Hemeproteins; C020753:hemozoin