title: Quantitative determination of Plasmodium vivax gametocytes by real-time quantitative nucleic acid sequence-based amplification in clinical samples.
abstract: Microscopic detection of Plasmodium vivax gametocytes, the sexual life stage of this malaria parasite, is insensitive because P. vivax parasitaemia is low. To detect and quantify gametocytes a more sensitive, quantitative real-time Pvs25-QT-NASBA based on Pvs25 mRNA was developed and tested in two clinical sample sets from three different continents. Pvs25-QT-NASBA is highly reproducible with low inter-assay variation and reaches sensitivity approximately 800 times higher than conventional microscopic gametocyte detection. Specificity was tested in 104 samples from P. vivax-, P. falciparum-, P. malariae-, and P. ovale-infected patients. All non-vivax samples were negative in the Pvs25-QT-NASBA; out of 74 PvS18-QT-NASBA positive samples 69% were positive in the Pvs25-QT-NASBA. In a second set of 136 P. vivax microscopically confirmed samples, gametocyte prevalence was 8%, whereas in contrast 66% were positive by Pvs25-QT-NASBA. The data suggest that the human P. vivax gametocyte reservoir is much larger when assessed by Pvs25-QT-NASBA than by microscopy.
authors.affiliation: Department of Medical Microbiology, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands. martijnbeurskens@gmail.com
authors.forename: Martijn
authors.initials: M
authors.lastname: Beurskens
authors.forename: Pètra
authors.initials: P
authors.lastname: Mens
authors.forename: Henk
authors.initials: H
authors.lastname: Schallig
authors.forename: Din
authors.initials: D
authors.lastname: Syafruddin
authors.forename: Puji Budi Setia
authors.initials: PB
authors.lastname: Asih
authors.forename: Rob
authors.initials: R
authors.lastname: Hermsen
authors.forename: Robert
authors.initials: R
authors.lastname: Sauerwein
mesh_terms: D000818:Animals; D001483:Base Sequence; D006801:Humans; D016780:Malaria, Vivax / Q000469:parasitology*; D021141:Nucleic Acid Amplification Techniques / Q000379:methods*; D010966:Plasmodium vivax / Q000166:cytology / Q000235:genetics / Q000302:isolation & purification*; D015800:Protozoan Proteins / Q000235:genetics; D012313:RNA / Q000235:genetics; D016053:RNA, Protozoan / Q000235:genetics; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
chemical_list: D015800:Protozoan Proteins; D016053:RNA, Protozoan; D012313:RNA