title: Detection and species identification of Leishmania DNA from filter paper lesion impressions for patients with American cutaneous leishmaniasis.
abstract: BACKGROUND
  Traditional detection of Leishmania from ulcers involves collection of invasive specimens that cause discomfort, require technical expertise, and carry risks of invasive procedures. We compared traditional diagnostic methods with a molecular noninvasive filter paper-based method for the diagnosis of cutaneous leishmaniasis.
  
  
  METHODS
  Consecutive patients presenting to the Leishmania Clinic at Hospital Nacional Cayetano Heredia were enrolled. Polymerase chain reaction (PCR) was performed on lesion scrapings, aspirates, and filter paper impressions. The reference standard was any 2 of 5 tests positive: smear, aspirate culture, invasive-specimen PCR (scrapings and aspirates), filter paper PCR, and leishmanin skin test. Outcome measures were sensitivity and specificity. Leishmania speciation was performed by PCR-restriction fragment length polymorphism (RFLP) of positive specimens.
  
  
  RESULTS
  Forty-five patients with 66 lesions were enrolled. Of 52 lesions diagnosed as cutaneous leishmaniasis, 50 were positive by PCR of invasive specimens versus 48 by PCR of filter papers (P=.930). Sensitivity and specificity of PCR on invasively obtained specimens were 94.2% (95% confidence interval [CI], 87.9%-100%) and 92.9% (95% CI, 79.4%-100%). Sensitivity and specificity of filter paper PCR were 92.3% (95% CI, 85.1%-99.5%) and 100%. Culture, smear, and leishmanin skin test all had inferior sensitivities, compared with PCR of invasive or noninvasive specimens (P<.001). Of 50 specimens positive by PCR, 19 had sufficient DNA for PCR-RFLP analysis.
  
  
  CONCLUSIONS
  Filter paper PCR constitutes a sensitive and specific alternative to traditional diagnostic assays. This novel, rapid, well-tolerated method has the potential for widespread use in the field and in pediatric populations where traditional specimen collection is most difficult to perform, and can potentially be used for rapid species identification.
authors: Tropical Disease Unit, Division of Infectious Diseases, Toronto General Hospital, Toronto, Canada. andrea.boggild@utoronto.ca
authors: Andrea K
authors: AK
authors: Boggild
authors: Braulio Mark
authors: BM
authors: Valencia
authors: Diego
authors: D
authors: Espinosa
authors: Nicolas
authors: N
authors: Veland
authors: Ana Pilar
authors: AP
authors: Ramos
authors: Jorge
authors: J
authors: Arevalo
authors: Alejandro
authors: A
authors: Llanos-Cuentas
authors: Donald E
authors: DE
authors: Low
mesh_terms: D000293:Adolescent; D000368:Aged; D002648:Child; D002675:Child, Preschool; D004247:DNA / Q000032:analysis* / Q000235:genetics; D005260:Female; D006801:Humans; D007891:Leishmania / Q000145:classification* / Q000235:genetics; D016773:Leishmaniasis, Cutaneous / Q000175:diagnosis / Q000469:parasitology*; D008297:Male; D008875:Middle Aged; D010568:Peru; D016133:Polymerase Chain Reaction / Q000379:methods*; D012680:Sensitivity and Specificity; D012867:Skin / Q000469:parasitology; D013045:Species Specificity; D013048:Specimen Handling / Q000379:methods
chemical_list: D004247:DNA