title: Comparison of Giemsa microscopy with nested PCR for the diagnosis of malaria in North Gondar, north-west Ethiopia.
abstract: BACKGROUND
  Malaria remains one of the leading communicable diseases in Ethiopia. Early diagnosis combined with prompt treatment is one of the main strategies for malaria prevention and control. Despite its limitation, Giemsa microscopy is still considered to be the gold standard for malaria diagnosis. This study aimed to compare the performance of Giemsa microscopy with nested polymerase chain reaction (nPCR) for the diagnosis of malaria in north-west Ethiopia.
  
  
  METHODS
  A cross sectional study was conducted in public health facilities in North Gondar, from March 2013 to April 2013. A total number of 297 subjects with suspected malaria were enrolled in the study. Finger-prick blood samples were collected and examined for Plasmodium parasites using Giemsa microscopy and standard nPCR.
  
  
  RESULTS
  Among the study participants, 61.6% (183/297) patients tested positive for malaria by Giemsa microscopy of which, 72.1% (132/183) and 27.9% (51/183) were diagnosed as Plasmodium falciparum and Plasmodium vivax, respectively. By nPCR, 73.1% (217/297) were malaria-positive. Among microscopy-negative samples, 13.1% (39/297) samples turned malaria-positive in nPCR. In nPCR, the rate of mixed Plasmodium infections was 4.7% (14/297) and 3.03% (9/297) were positive for Plasmodium ovale. Using nPCR as reference the sensitivity, specificity, positive predictive and negative predictive values of Giemsa microscopy were 82.0%, 93.8%, 97.3% and 65.8%, respectively, with a good agreement (κ = 0.668) to nested PCR. The sensitivity and specificity of Giemsa microscopy in identifyingP. falciparium infections were 74.0% and 87.4% and 63.2% and 96.5% for P. vivax infections, respectively.
  
  
  CONCLUSIONS
  Although Giemsa microscopy remains the gold standard for malaria diagnosis in resource-limited environments, its sensitivity and specificity as compared to nPCR is limited suggesting exploration of novel rapid and simplified molecular techniques for malaria-endemic countries. A high rate of misclassification and misidentification highlights the importance of adequate training for staff involved in malaria diagnosis.
authors.forename: Abebe
authors.initials: A
authors.lastname: Alemu
authors.forename: Hans-Peter
authors.initials: HP
authors.lastname: Fuehrer
authors.affiliation: Department of Medical Parasitology, School of Biomedical and Laboratory Sciences, College of Medicine and Health Sciences, University of Gondar, Gondar, Ethiopia. ggebeyaw@yahoo.com.
authors.forename: Gebeyaw
authors.initials: G
authors.lastname: Getnet
authors.forename: Afework
authors.initials: A
authors.lastname: Kassu
authors.forename: Sisay
authors.initials: S
authors.lastname: Getie
authors.forename: Harald
authors.initials: H
authors.lastname: Noedl
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001769:Blood / Q000469:parasitology; D002648:Child; D002675:Child, Preschool; D060085:Coinfection / Q000175:diagnosis / Q000469:parasitology; D003430:Cross-Sectional Studies; D005002:Ethiopia; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008288:Malaria / Q000175:diagnosis* / Q000469:parasitology; D008297:Male; D008853:Microscopy / Q000379:methods*; D008875:Middle Aged; D010963:Plasmodium falciparum / Q000302:isolation & purification*; D041122:Plasmodium ovale / Q000302:isolation & purification*; D010966:Plasmodium vivax / Q000302:isolation & purification*; D016133:Polymerase Chain Reaction / Q000379:methods*; D012680:Sensitivity and Specificity; D013194:Staining and Labeling / Q000379:methods; D055815:Young Adult