title: Age-dependent distribution of Plasmodium falciparum gametocytes quantified by Pfs25 real-time QT-NASBA in a cross-sectional study in Burkina Faso.
abstract: Sexual stages of Plasmodium falciparum play a key role in the transmission of malaria. Studies on gametocytes are generally based on microscopic detection, but more sensitive detection methods for P. falciparum gametocytes frequently detect sub-patent gametocytes. We used Pfs25 mRNA quantitative-nucleic acid sequence-based amplification (QT-NASBA) to quantify gametocytes in 412 samples from a cross-sectional study in Burkina Faso, covering all age groups, to determine age-related patterns in gametocyte carriage and gametocyte density. The more sensitive QT-NASBA technique gave estimates of gametocyte prevalence 3.3-fold higher than microscopy (70.1% versus 21.4%, respectively). Prevalence of gametocytes significantly decreased with age. Our data suggest that asexual parasite densities are primarily responsible for the age-related decrease of gametocyte prevalence, possibly because of developing asexual stage immunity. Gametocyte densities decrease also with age, primarily because of decreasing asexual parasite densities; only a small but significant age effect on gametocyte density may be caused by developing sexual stage-specific immunity.
authors.affiliation: Department of Medical Microbiology, University Medical Centre Nijmegen, Nijmegen, The Netherlands. andre_lin_o@yahoo.fr
authors.forename: André Lin
authors.initials: AL
authors.lastname: Ouédraogo
authors.forename: Petra
authors.initials: P
authors.lastname: Schneider
authors.forename: Marcel
authors.initials: M
authors.lastname: de Kruijf
authors.forename: Issa
authors.initials: I
authors.lastname: Nébié
authors.forename: Jan Peter
authors.initials: JP
authors.lastname: Verhave
authors.forename: Nadine
authors.initials: N
authors.lastname: Cuzin-Ouattara
authors.forename: Robert W
authors.initials: RW
authors.lastname: Sauerwein
mesh_terms: D000293:Adolescent; D000328:Adult; D017677:Age Distribution; D000818:Animals; D002050:Burkina Faso / Q000453:epidemiology; D002648:Child; D002675:Child, Preschool; D003430:Cross-Sectional Studies; D006801:Humans; D016778:Malaria, Falciparum / Q000453:epidemiology* / Q000469:parasitology*; D010963:Plasmodium falciparum / Q000254:growth & development* / Q000302:isolation & purification*; D015800:Protozoan Proteins / Q000302:isolation & purification*; D021161:Self-Sustained Sequence Replication
chemical_list: C071284:Pfs25 protein, Plasmodium falciparum; D015800:Protozoan Proteins