Acute Malaria in Malawian Children and Adults is Characterized by Thrombocytopenia That Normalizes in Convalescence

Abstract

Background

Plasmodium falciparum malaria has been linked with significant perturbations of the peripheral cell-mediated immune system during acute phase. Some of these changes include lower than normal platelet counts. Although the exact mechanisms that drive thrombocytopenia in P. falciparum malaria are not fully known, a number of hypotheses have been proposed. We conducted two sets of studies with one aimed at determining platelet counts in Malawian children, and the other in adults during acute P. falciparum malaria and a month post treatment.

Materials and Methods

We recruited a total of 113 HIV-uninfected children with acute malaria [n=54 with uncomplicated malaria (UCM), n=30 with severe malarial anemia (SMA), n=29 presenting with cerebral malaria (CM)]. We also recruited 42 HIV-uninfected healthy controls. Out of the 113 participants with malaria, 73 (65%) [n=34 (63%) UCM, n=21 (70%) SMA and n=18 (62%) CM] were successfully followed-up one month after treatment. A 5mL peripheral blood sample was collected for platelet count using HMX Haematological Analyzer analysis both at baseline (acute malaria) and at follow-up a month later. Platelet counts were also determined in blood samples of 106 HIV-uninfected adults, 47 of whom presented with UCM and 29 with severe malaria (SM) and these counts were compared to those of 30 healthy controls. Of the malaria cases, platelet counts for 44 UCM and 21 SM were determined again during follow-up a month after treatment.

Results

In both children and adults, platelet counts were significantly lower during acute disease compared to the levels in the healthy controls with the lowest levels observed in CM (children) or SM (adults). These lower than normal levels increased close to normal levels a month post treatment.

Conclusion

P. falciparum malaria in Malawian children and adults was characterized by profound thrombocytopenia which recovered during convalescence.

Keywords:

• acute malaria
• platelet counts
• children and adults
• convalescence

Acknowledgments

The authors would like to thank the children who took part in this study and their respective parents or relatives for allowing them to participate. We also thank all adult participants for consenting to take part in the study.

Author Contributions

All authors made a significant contribution to the work reported, whether that is in the conception, study design, execution, acquisition of data, analysis and interpretation, or in all these areas; took part in drafting, revising or critically reviewing the article; gave final approval of the version to be published; have agreed on the journal to which the article has been submitted; and agree to be accountable for all aspects of the work.

Disclosure

All authors for this study declare no conflicts of interest.

Additional information

Funding

Funding for the pediatric study was obtained from the Gates Malaria Partnership, which was financially supported by the Bill and Melinda Gates Foundation [Grant Number: OPP51941] whereas the adult study was a Pre-MSc grant offered by Malawi-Liverpool Wellcome Trust Clinical Programme (MLW) which is financially supported by the Wellcome Trust, UK.