title: The prognostic value of schizontaemia in imported Plasmodium falciparum malaria.
abstract: BACKGROUND
  In Plasmodium falciparum infection, peripheral parasite counts do not always correlate well with the sequestered parasite burden. As erythrocytes parasitized with mature trophozoites and schizonts have a high tendency to adhere to the microvascular endothelium, they are often absent in peripheral blood samples. The appearance of schizonts in peripheral blood smears is thought to be a marker of high sequestered parasite burden and severe disease. In the present study, the value of schizontaemia as an early marker for severe disease in non-immune individuals with imported malaria was evaluated.
  
  
  METHODS
  All patients in the Rotterdam Malaria Cohort diagnosed with P. falciparum malaria between 1 January 1999 and 1 January 2012 were included. Thick and thin blood films were examined for the presence of schizontaemia. The occurrence of WHO defined severe malaria was the primary endpoint. The diagnostic performance of schizontaemia was compared with previously evaluated biomarkers C-reactive protein and lactate.
  
  
  RESULTS
  Schizonts were present on admission in 49 of 401 (12.2%) patients. Patients with schizontaemia were more likely to present with severe malaria, a more complicated course and had longer duration of admission in hospital. Schizontaemia had a specificity of 0.95, a sensitivity of 0.53, a negative predictive value of 0.92 and a positive predictive value of 0.67 for severe malaria. The presence of schizonts was an independent predictor for severe malaria.
  
  
  CONCLUSIONS
  Absence of schizonts was found to be a specific marker for exclusion of severe malaria. Presence of schizonts on admission was associated with a high positive predictive value for severe malaria. This may be of help to identify patients who are at risk of a more severe course than would be expected when considering peripheral parasitaemia alone.
authors.affiliation: Department of Internal Medicine, Harbour Hospital, Rotterdam, The Netherlands.
authors.forename: Marlies E
authors.initials: ME
authors.lastname: van Wolfswinkel
authors.forename: Mariana
authors.initials: M
authors.lastname: de Mendonça Melo
authors.forename: Klaske
authors.initials: K
authors.lastname: Vliegenthart-Jongbloed
authors.forename: Rob
authors.initials: R
authors.lastname: Koelewijn
authors.forename: Jaap J
authors.initials: JJ
authors.lastname: van Hellemond
authors.forename: Perry J
authors.initials: PJ
authors.lastname: van Genderen
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001769:Blood / Q000469:parasitology; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007902:Length of Stay; D016778:Malaria, Falciparum / Q000175:diagnosis / Q000469:parasitology* / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D009426:Netherlands; D018512:Parasitemia / Q000175:diagnosis* / Q000469:parasitology*; D010963:Plasmodium falciparum / Q000166:cytology / Q000302:isolation & purification*; D011237:Predictive Value of Tests; D011379:Prognosis; D052939:Schizonts; D012680:Sensitivity and Specificity; D014195:Travel; D016896:Treatment Outcome; D055815:Young Adult