Hematological Impairments in Recurrent Plasmodium Vivax Infected Patients

Abstract

SUMMARY:The hematological parameters were assayed in Plasmodium vivax patients with only one infection, two infections, three infections and more than three malarial infections during a period of six months. A steady fall in the levels of hemoglobin as well as packed cell volume (PCV) level was observed with increasing number of infections. The malarial patients showed a progressive decrease in RBC level with increasing number of attacks. The decrease in the hematological indices was statistically significant at all levels of parasitemia. There was a marked increase in the osmotic fragility of the malarial erythrocytes when compared to that of controls. During repeated malarial attacks, significant decrease in MCH (p<0.05) and MCHC (p<0.01) and increase in the MCV level (p <0.05) and Heinz body formation (p<0.001) were observed. Parasite density significantly influenced the fragility of the erythrocytes, Heinz body formation, MCV, MCH and MCHC levels. Thus, the erythrocytes of the patients repeatedly infected with Plasmodium vivax parasite are subjected to structural and functional impairment, ultimately culminating in anemia.

Suppression of erythroid development in vitro by Plasmodium vivax

“…Numerous reports have shown that P. vivax can be associated with severe anaemia [2-12]. Haematologic profiles of pancytopaenia in blood and bone marrow [16] and dyserythropoiesis in bone marrow [15] have been reported in vivax malaria patients.…”

“…Most published reports on malaria-associated anaemia focus on Plasmodium falciparum with Plasmodium vivax being less well studied [1]. However, growing evidence from several geographic regions has demonstrated that P. vivax malaria is associated with a higher frequency and more severe anaemia [2-12]. Several cases of patients infected with P. vivax that resulted in severe disease and death were found to have syndromes resembling those commonly observed with falciparum malaria [8,13,14].…”

The anaemia of Plasmodium vivax malaria

“…Thus, it appears that P. falciparum and P. vivax have evolved two different means of escaping splenic filtration. In both vivax and falciparum malaria, parasitized, and possibly non-parasitized, red cells are hypothesized to be more fragile than red cells in non-infected individuals and more prone to damage from shear stresses [72,81,110,112]. This process is potentially a more important cause of red cell loss in falciparum malaria since in this disease, major sequestration in the microvasculature impedes the passage of circulating erythrocytes and erythrocyte rosettes [82].…”

“…If this occurs before an individual’s haemoglobin concentration has returned to normal following primary infection, the haematological effects are likely to be additive though direct evidence supporting this postulate is limited [33,72,150]. The likelihood of repeat heterologous infection, and the probability that it occurs before complete haematological recovery, is a function of, among other things, the relapse pattern of local P. vivax strains and the entomological inoculation rate, both of which are also likely to affect the rate of genetic recombination and hence parasite population diversity [151].…”

A case of Plasmodium vivax malaria associated with severe autoimmune hemolytic anaemia

“…[7] However, recent evidence shows that P. vivax-induced anemia is more frequent and more severe. [8][9][10] According to various theories factors contributing to anemia in vivax malaria are same as those mentioned in Table 1 but the role of immune-mediated hemolysis has been better attributed to anemia in falciparum malaria. [11] In autoimmune hemolytic anemia, antibodies are directed against antigens on the surface of RBC.…”