Changes in the total leukocyte and platelet counts in Papuan and non Papuan adults from northeast Papua infected with acute Plasmodium vivax or uncomplicated Plasmodium falciparum malaria

Background There are limited data on the evolution of the leukocyte and platelet counts in malaria patients. Methods In a clinical trial of chloroquine vs. chloroquine plus doxycycline vs. doxycycline alone against Plasmodium vivax (n = 64) or Plasmodium falciparum (n = 98) malaria, the total white cell (WCC) and platelet (PLT) counts were measured on Days 0, 3, 7 and 28 in 57 indigenous Papuans with life long malaria exposure and 105 non Papuan immigrants from other parts of Indonesia with limited malaria exposure. Results The mean Day 0 WCC (n = 152) was 6.492 (range 2.1–13.4) × 10 9 /L and was significantly lower in the Papuans compared to the non Papuans: 5.77 × 10 9 /L vs. 6.86 × 10 9 /L, difference = -1.09 [(95% CI -0.42 to -1.79 × 10 9 /L), P = 0.0018]. 14 (9.2%) and 9 (5.9%) patients had leukopaenia (<4.0 × 10 9 /L) and leukocytosis (>10.0 × 10 9 /L), respectively. By Day 28, the mean WCC increased significantly (P = 0.0003) from 6.37 to 7.47 × 10 9 /L (73 paired values) and was similar between the two groups. Ethnicity was the only WCC explanatory factor and only on Day 0. The mean Day 0 platelet count (n = 151) was 113.0 (range 8.0–313.0) × 10 9 /L and rose significantly to 186.308 × 10 9 /L by Day 28 (P < 0.0001). There was a corresponding fall in patient proportions with thrombocytopaenia (<150 × 10 9 /L): 119/151 (78.81%) vs. 16/73 (21.92%, P < 0.00001). Papuan and non Papuan mean platelet counts were similar at all time points. Only malaria species on Day 0 was a significant platelet count explanatory factor. The mean D0 platelet counts were significantly lower (P = 0.025) in vivax (102.022 × 10 9 /L) vs. falciparum (122.125 × 10 9 /L) patients. Conclusion Changes in leukocytes and platelets were consistent with other malaria studies. The Papuan non Papuan difference in the mean Day 0 WCC was small but might be related to the difference in malaria exposure.