title: Detection and clinical manifestation of placental malaria in southern Ghana.
abstract: BACKGROUND
  Plasmodium falciparum can be detected by microscopy, histidine-rich-protein-2 (HRP2) capture test or PCR but the respective clinical relevance of the thereby diagnosed infections in pregnant women is not well established.
  
  
  METHODS
  In a cross-sectional, year-round study among 839 delivering women in Agogo, Ghana, P. falciparum was screened for in both, peripheral and placental blood samples, and associations with maternal anaemia, low birth weight (LBW) and preterm delivery (PD) were analysed.
  
  
  RESULTS
  In peripheral blood, P. falciparum was observed in 19%, 34%, and 53% by microscopy, HRP2 test, and PCR, respectively. For placental samples, these figures were 35%, 41%, and 59%. Irrespective of diagnostic tool, P. falciparum infection increased the risk of anaemia. Positive peripheral blood results of microscopy and PCR were not associated with LBW or PD. In contrast, the HRP2 test performed well in identifying women at increased risk of poor pregnancy outcome, particularly in case of a negative peripheral blood film. Adjusting for age, parity, and antenatal visits, placental HRP2 was the only marker of infection associated with LBW (adjusted odds ratio (aOR), 1.5 (95%CI, 1.0-2.2)) and, at borderline statistical significance, PD (aOR, 1.4 (1.0-2.1)) in addition to anaemia (aOR, 2.3 (1.7-3.2)). Likewise, HRP2 in peripheral blood of seemingly aparasitaemic women was associated with PD (aOR, 1.7 (1.0-2.7)) and anaemia (aOR, 2.1 (1.4-3.2)).
  
  
  CONCLUSIONS
  Peripheral blood film microscopy not only underestimates placental malaria. In this highly endemic setting, it also fails to identify malaria as a cause of foetal impairment. Sub-microscopic infections detected by a HRP2 test in seemingly aparasitaemic women increase the risks of anaemia and PD. These findings indicate that the burden of malaria in pregnancy may be even larger than thought and accentuate the need for effective anti-malarial interventions in pregnancy.
authors.affiliation: Institute of Tropical Medicine and International Health, Charité--University Medicine, Berlin, Germany. frank.mockenhaupt@charite.de
authors.forename: Frank P
authors.initials: FP
authors.lastname: Mockenhaupt
authors.forename: George
authors.initials: G
authors.lastname: Bedu-Addo
authors.forename: Christiane
authors.initials: C
authors.lastname: von Gaertner
authors.forename: Renate
authors.initials: R
authors.lastname: Boyé
authors.forename: Katrin
authors.initials: K
authors.lastname: Fricke
authors.forename: Iris
authors.initials: I
authors.lastname: Hannibal
authors.forename: Filiz
authors.initials: F
authors.lastname: Karakaya
authors.forename: Marieke
authors.initials: M
authors.lastname: Schaller
authors.forename: Ulrike
authors.initials: U
authors.lastname: Ulmen
authors.forename: Patrick A
authors.initials: PA
authors.lastname: Acquah
authors.forename: Ekkehart
authors.initials: E
authors.lastname: Dietz
authors.forename: Teunis A
authors.initials: TA
authors.lastname: Eggelte
authors.forename: Ulrich
authors.initials: U
authors.lastname: Bienzle
mesh_terms: D000818:Animals; D000953:Antigens, Protozoan / Q000032:analysis; D000962:Antimalarials / Q000627:therapeutic use; D005260:Female; D005869:Ghana / Q000453:epidemiology; D006801:Humans; D016778:Malaria, Falciparum / Q000175:diagnosis* / Q000453:epidemiology / Q000469:parasitology / Q000517:prevention & control; D008859:Microscopy, Polarization / Q000379:methods*; D010922:Placenta Diseases / Q000453:epidemiology / Q000469:parasitology* / Q000517:prevention & control; D010963:Plasmodium falciparum / Q000302:isolation & purification* / Q000378:metabolism; D016133:Polymerase Chain Reaction / Q000379:methods; D011247:Pregnancy; D015597:Pregnancy Complications, Parasitic / Q000453:epidemiology / Q000469:parasitology* / Q000517:prevention & control; D015800:Protozoan Proteins / Q000032:analysis; D011739:Pyrimethamine / Q000627:therapeutic use
chemical_list: D000953:Antigens, Protozoan; D000962:Antimalarials; C514457:HRP-2 antigen, Plasmodium falciparum; D015800:Protozoan Proteins; D011739:Pyrimethamine