Extensive dynamics of Plasmodium falciparum densities, stages and genotyping profiles.
BACKGROUND
Individuals living in areas of high malaria transmission often have different Plasmodium falciparum clones detected in the peripheral blood over time. The aim of this study was to assess the dynamics of asymptomatic P. falciparum infections in a few hours intervals.


METHODS
Capillary blood samples were collected 6-hourly during five days from asymptomatic children in a highly endemic area in Tanzania. Parasite densities and maturation stages were investigated by light microscopy. Types and number of clones were analysed by PCR based genotyping of the polymorphic merozoite surface proteins 1 and 2 genes.


RESULTS
Parasite densities and maturation stages fluctuated 48-hourly with a gradual shift into more mature forms. Various genotyping patterns were observed in repeated samples over five days with only few samples with identical profiles. Up to six alleles differed in samples collected six hours apart in the same individual.


CONCLUSIONS
This detailed assessment highlights the extensive within-host dynamics of P. falciparum populations and the limitations of single blood samples to determine parasite densities, stages and genotyping profiles in a malaria infected individual.
Färnert
Anna
A
Unit of Infectious Diseases, Department of Medicine, Karolinska Institutet, Karolinska University Hospital, Stockholm, Sweden. anna.farnert@ki.se
Lebbad
Marianne
M
Faraja
Lea
L
Rooth
Ingegerd
I
D000483:Alleles; D000818:Animals; D000953:Antigens, Protozoan / Q000235:genetics; D001769:Blood / Q000469:parasitology*; D002648:Child; D016054:DNA, Protozoan / Q000235:genetics; D019353:Endemic Diseases; D005838:Genotype; D006801:Humans; D016778:Malaria, Falciparum / Q000453:epidemiology / Q000469:parasitology*; D020066:Merozoite Surface Protein 1 / Q000235:genetics; D008853:Microscopy; D010963:Plasmodium falciparum / Q000145:classification* / Q000166:cytology / Q000235:genetics / Q000254:growth & development*; D016133:Polymerase Chain Reaction / Q000379:methods; D015800:Protozoan Proteins / Q000235:genetics; D013636:Tanzania / Q000453:epidemiology
D000953:Antigens, Protozoan; D016054:DNA, Protozoan; D020066:Merozoite Surface Protein 1; D015800:Protozoan Proteins; C065974:merozoite surface protein 2, Plasmodium