PCR and direct agglutination as Leishmania infection markers among healthy Nepalese subjects living in areas endemic for Kala-Azar.
OBJECTIVE
To compare a PCR assay and direct agglutination test (DAT) for the detection of potential markers of Leishmania infection in 231 healthy subjects living in a kala-azar endemic focus of Nepal.


METHODS
The sample was composed of 184 (80%) persons without any known history of KA and not living in the same house as known kala-azar cases (HNK), 24 (10%) Healthy Household Contacts (HHC) and 23 (10%) past kala-azar cases which had been successfully treated (HPK).


RESULTS
PCR and DAT positivity scores were, respectively: HNK, 17.6% and 5.6%; HHC, 12.5% and 20.8%; HPK, 26.1% and 95.7%. The ratio PCR-positives/DAT-positives was significantly higher in HNK (ratio = 3.1) than in HHC (ratio = 0.6, P = 0.036) and in HPK (ratio = 0.2, P = 0.012). The ratio PCR-positives/DAT-positives did not significantly differ between HHC (ratio = 0.6) and HPK (ratio = 0.2, P = 0.473). The positive agreement index between PCR and DAT in HNK was 5%; in HHC, 0%; in HPK, 43%.


CONCLUSIONS
Our study highlights the specific character of PCR and DAT for the exploration of Leishmania asymptomatic infections. PCR is probably more informative for very recent infections among HNK, while DAT provides more information among HHC and HPK, a feature likely related to the power of serology to track less recent infections.
Bhattarai
Narayan Raj
NR
Unit of Molecular Parasitology, Institute of Tropical Medicine, Antwerpen, Belgium.
Van der Auwera
Gert
G
Khanal
Basudha
B
De Doncker
Simonne
S
Rijal
Suman
S
Das
Murari Lal
ML
Uranw
Surendra
S
Ostyn
Bart
B
Praet
Nicolas
N
Speybroeck
Niko
N
Picado
Albert
A
Davies
Clive
C
Boelaert
Marleen
M
Dujardin
Jean-Claude
JC
D000372:Agglutination Tests / Q000379:methods; D000818:Animals; D000913:Antibodies, Protozoan / Q000097:blood; D000953:Antigens, Protozoan; D015415:Biomarkers / Q000097:blood; D016054:DNA, Protozoan / Q000097:blood; D006801:Humans; D007893:Leishmania donovani / Q000302:isolation & purification; D007898:Leishmaniasis, Visceral / Q000175:diagnosis* / Q000453:epidemiology*; D008403:Mass Screening / Q000379:methods; D009390:Nepal; D016133:Polymerase Chain Reaction / Q000379:methods
D000913:Antibodies, Protozoan; D000953:Antigens, Protozoan; D015415:Biomarkers; D016054:DNA, Protozoan