Microrheologic dysfunctions in blood during malaria.

Among the Plasmodium variants that cause human malaria, vivax malaria is considered to be non-malignant. Recent research has indicated that severe vivax infection can turnout to be as pathological as falciparum. This review evidences microrheologic pathology in vivax malaria, similar to that as seen in malignant falciparum. The parasite invasion, internalization and growth in the RBC lead to membrane rigidification and progressive loss of deformability, rosetting and cytoadherence, enhanced aggregation, clumpy, non-deforming, sticky aggregates and chronic sedimentation profiles. A model that reflects the net effect of these changes is of clinical value to establish disease severity in specific malaria. In this respect an artificial neural network (ANN) model, implemented in malaria severity analysis, is discussed. Results of this model suggest that a good degree of severity classification (60 to 100%) can be achieved even with small sample size (malaria samples n = 12, normal = 10). With larger sample size, ANN may be very apt as microrheological model for severity analysis.

Influence of malaria parasite (P. vivax) on erythrocyte aggregation: a study based on dynamic imaging and analysis.

Malaria due to P. vivax (PV) is prevalent in many countries. The present work is aimed to determine the cell-cell interaction through formation of aggregates under dynamic conditions. Blood samples are obtained from patients (n=11) suffering from PV malaria, and the normal subjects (n=10) in test tubes containing citrate phosphate dextrose (10:1.4), as an anticoagulant. The signature analysis of infected erythrocytes shows significant alterations in their shape and membrane. For aggregation analysis, erythrocyte suspension in plasma at hematocrit 5%, was placed in a glass chamber and mounted vertically on the stage of the video-microscope system. The aggregate images thus acquired show erythrocytes adhering with each other to form mash-like structures. With increase in parasitaemia, the erythrocytes show hyper-aggregation compared to that of normal cells. By processing of the sequence of recorded images during sedimentation, the various aggregation parameters are obtained. These parameters show that the formed aggregates are compact which produce distinct changes in sedimentation pattern with significantly higher sedimentation velocity compared to that in healthy blood samples. These changes in malaria could partly be responsible for alteration in blood flow through microcirculatory system.