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PCR and direct agglutination as Leishmania infection markers among healthy Nepalese subjects living in areas endemic for Kala-Azar |
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| Authors: | Narayan Raj Bhattarai Gert Van der Auwera Basudha Khanal Simonne De Doncker Suman Rijal Murari Lal Das Surendra Uranw Bart Ostyn Nicolas Praet Niko Speybroeck Albert Picado Clive Davies Marleen Boelaert Jean-Claude Dujardin |
| Affiliation: | Unit of Molecular Parasitology, Institute of Tropical Medicine, Antwerpen, Belgium; Department of Microbiology, B. P. Koirala Institute of Health Sciences, Dharan, Nepal; Department of Internal Medicine, B. P. Koirala Institute of Health Sciences, Dharan, Nepal; Department of Public Health, Institute of Tropical Medicine, Antwerpen, Belgium; Animal Health Department, Institute of Tropical Medicine, Antwerpen, Belgium; Ecole de santépublique, UniversitéCatholique de Louvain, Clos Chapelle-aux-Champs, Bruxelles, Belgium; London School of Hygiene and Tropical Medicine, London, UK; Department of Biomedical Sciences, University of Antwerpen, Belgium |
| Abstract: | 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. |
| Keywords: | Kala-azar Nepal PCR DAT asymptomatic infections |