Journal of Tropical Pediatrics Advance Access originally published online on December 2, 2005
Journal of Tropical Pediatrics 2006 52(4):254-259; doi:10.1093/tropej/fmi110
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Factors Contributing to the Development of Anaemia in Plasmodium falciparum Malaria: What about Drug-Resistant Parasites?
a Centre for Tropical Clinical Pharmacology and Therapeutics, University of Ghana Medical School, Accra, Ghana
b Noguchi Memorial Institute for Medical Research, Legon, Ghana
c Department of Child Health, Korle Bu Teaching Hospital, Accra, Ghana
d Centre for Medical Parasitology, Department of Clinical Microbiology, Copenhagen University Hospital (Rigshospitalet), and Institute of Medical Microbiology and Immunology, University of Copenhagen, Copenhagen, Denmark
Correspondence: Neils Ben Quashie, Centre for Tropical Clinical Pharmacology and Therapeutic, University of Ghana Medical School, P.O. Box 4236, Accra, Ghana. E-mail <nquashie{at}noguchi.mimcom.net>.
A major manifestation of complicated malaria especially among children is severe anaemia, the pathogenesis of which is not well understood. Among other factors, suppression of the bone marrow's response to erythropoietin, which is rapidly reversed after successful treatment of the malaria, has been implicated in its pathogenesis. Since resolution of malaria restores erythropoiesis, we hypothesized that drug-resistant strains of Plasmodium falciparum would increase the risk of severe anaemia developing from initially uncomplicated malaria. Using both in vivo and in vitro drug-sensitivity tests we compared the prevalence of drug-resistant malaria between severe malarial anaemia (SA) and non-anaemic malaria (NAM) patients. Assessment of treatment outcome using the WHO in vivo criteria showed no significant difference in parasite resistance between the two groups. The mean parasite clearance time was also comparable. Treatment failures of about 14 per cent and 12 per cent were observed between SA and NAM patients respectively. The in vitro drug susceptibility test showed overall mean IC50 values of 0.41x10–6 mol/l and 0.32x10–6 mol/l blood for SA and NAM groups respectively. Geometric mean pre-treatment blood levels of chloroquine did not differ much between the two groups. Findings from this study could not therefore implicate drug-resistant parasites in the pathogenesis of severe malarial anaemia.