Diagnostic accuracy of a new Leishmania PCR for clinical visceral leishmaniasis in Nepal and its role in diagnosis of disease.
OBJECTIVE
To develop a new PCR for Leishmania detection and to estimate its diagnostic accuracy in a visceral leishmaniasis (VL) endemic area.


METHODS
After providing the proof-of-concept, the diagnostic accuracy was estimated on blood from 247 non-endemic control persons and on blood and bone marrow from 173 confirmed VL, 39 probable VL and 87 non-VL patients from south-eastern Nepal.


RESULTS
The PCR showed a specificity of 99.64% [95% confidence interval (CI): 98.93-100%) on non-endemic controls and a sensitivity of 92.1% (95% CI: 87.6-96.6%) on blood and 92.9% (95% CI: 89-96.8%) on bone marrow from the confirmed VL patients. Leishmania DNA was detected in blood and bone marrow of 67.6% (95% CI: 50.8-80.9%) and 71.8% (95% CI: 56.2-83.5%) of the probable VL patients, respectively, and of 38.2% (95% CI: 28-49.4%) and 29.9% (95% CI: 21.3-40.2%) of the non-VL patients, respectively. The PCR showed 97% concordance with a positive DAT status while for a negative DAT status this was only 41.3% (kappa-index 0.416, 95% CI: 0.30-0.53).


CONCLUSIONS
Our findings indicate that PCR alone rather provides a marker for infection than a marker for disease and its role in VL diagnosis in endemic regions is discussed.
Deborggraeve
Stijn
S
Department of Parasitology, Institute of Tropical Medicine, Antwerp, Belgium. sdeborggraeve@itg.be
Boelaert
Marleen
M
Rijal
Suman
S
De Doncker
Simonne
S
Dujardin
Jean-Claude
JC
Herdewijn
Piet
P
Büscher
Philippe
P
D000818:Animals; D016054:DNA, Protozoan / Q000097:blood*; D019353:Endemic Diseases / Q000517:prevention & control; D005260:Female; D020459:Genes, rRNA / Q000235:genetics* / Q000276:immunology; D006801:Humans; D007893:Leishmania donovani / Q000235:genetics / Q000276:immunology* / Q000302:isolation & purification; D007898:Leishmaniasis, Visceral / Q000175:diagnosis* / Q000453:epidemiology / Q000235:genetics; D008297:Male; D009390:Nepal / Q000453:epidemiology; D017354:Point Mutation / Q000235:genetics* / Q000276:immunology; D016133:Polymerase Chain Reaction / Q000379:methods*; D012680:Sensitivity and Specificity
D016054:DNA, Protozoan