title: Diagnostic accuracy of PCR in gambiense sleeping sickness diagnosis, staging and post-treatment follow-up: a 2-year longitudinal study.
abstract: BACKGROUND
  The polymerase chain reaction (PCR) has been proposed for diagnosis, staging and post-treatment follow-up of sleeping sickness but no large-scale clinical evaluations of its diagnostic accuracy have taken place yet.
  
  
  RESULTS
  An 18S ribosomal RNA gene targeting PCR was performed on blood and cerebrospinal fluid (CSF) of 360 T. brucei gambiense sleeping sickness patients and on blood of 129 endemic controls from the Democratic Republic of Congo. Sensitivity and specificity (with 95% confidence intervals) of PCR for diagnosis, disease staging and treatment failure over 2 years follow-up post-treatment were determined. Reference standard tests were trypanosome detection for diagnosis and trypanosome detection and/or increased white blood cell concentration in CSF for staging and detection of treatment failure. PCR on blood showed a sensitivity of 88.4% (84.4-92.5%) and a specificity of 99.2% (97.7-100%) for diagnosis, while for disease staging the sensitivity and specificity of PCR on cerebrospinal fluid were 88.4% (84.8-91.9%) and 82.9% (71.2-94.6%), respectively. During follow-up after treatment, PCR on blood had low sensitivity to detect treatment failure. In cerebrospinal fluid, PCR positivity vanished slowly and was observed until the end of the 2 year follow-up in around 20% of successfully treated patients.
  
  
  CONCLUSIONS
  For T.b. gambiense sleeping sickness diagnosis and staging, PCR performed better than, or similar to, the current parasite detection techniques but it cannot be used for post-treatment follow-up. Continued PCR positivity in one out of five cured patients points to persistence of living or dead parasites or their DNA after successful treatment and may necessitate the revision of some paradigms about the pathophysiology of sleeping sickness.
authors.affiliation: Department of Parasitology, Institute of Tropical Medicine, Antwerp, Belgium.
authors.forename: Stijn
authors.initials: S
authors.lastname: Deborggraeve
authors.forename: Veerle
authors.initials: V
authors.lastname: Lejon
authors.forename: Rosine Ali
authors.initials: RA
authors.lastname: Ekangu
authors.forename: Dieudonné
authors.initials: D
authors.lastname: Mumba Ngoyi
authors.forename: Patient
authors.initials: P
authors.lastname: Pati Pyana
authors.forename: Médard
authors.initials: M
authors.lastname: Ilunga
authors.forename: Jean Pierre
authors.initials: JP
authors.lastname: Mulunda
authors.forename: Philippe
authors.initials: P
authors.lastname: Büscher
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001769:Blood / Q000469:parasitology; D002555:Cerebrospinal Fluid / Q000469:parasitology; D002648:Child; D016054:DNA, Protozoan / Q000235:genetics; D004275:DNA, Ribosomal / Q000235:genetics; D015023:Democratic Republic of the Congo; D005500:Follow-Up Studies; D006801:Humans; D008875:Middle Aged; D025202:Molecular Diagnostic Techniques / Q000379:methods*; D010274:Parasitology / Q000379:methods*; D016133:Polymerase Chain Reaction / Q000379:methods*; D012337:RNA, Ribosomal, 18S / Q000235:genetics; D012680:Sensitivity and Specificity; D014347:Trypanosoma brucei gambiense / Q000235:genetics / Q000302:isolation & purification*; D014353:Trypanosomiasis, African / Q000175:diagnosis*; D055815:Young Adult
chemical_list: D016054:DNA, Protozoan; D004275:DNA, Ribosomal; D012337:RNA, Ribosomal, 18S