Abstract
Leishmania donovani is the known causative agent of both cutaneous (CL) and visceral leishmaniasis in Sri Lanka. CL is considered to be under-reported partly due to relatively poor sensitivity and specificity of microscopic diagnosis. We compared robustness of three previously described polymerase chain reaction (PCR) based methods to detectLeishmania DNA in 38 punch biopsy samples from patients presented with suspected lesions in 2010. Both, Leishmaniagenus-specific JW11/JW12 KDNA and LITSR/L5.8S internal transcribed spacer (ITS)1 PCR assays detected 92% (35/38) of the samples whereas a KDNA assay specific forL. donovani (LdF/LdR) detected only 71% (27/38) of samples. All positive samples showed a L. donovani banding pattern upon HaeIII ITS1 PCR-restriction fragment length polymorphism analysis. PCR assay specificity was evaluated in samples containing Mycobacterium tuberculosis, Mycobacterium leprae, and human DNA, and there was no cross-amplification in JW11/JW12 and LITSR/L5.8S PCR assays. The LdF/LdR PCR assay did not amplify M. leprae or human DNA although 500 bp and 700 bp bands were observed in M. tuberculosis samples. In conclusion, it was successfully shown in this study that it is possible to diagnose Sri Lankan CL with high accuracy, to genus and species identification, using Leishmania DNA PCR assays.
Highlights
In spite of the Public Health importance of cutaneous leishmaniasis (CL) in Sri Lanka, diagnosis continues to be mostly based on clinical features and traditional diagnostic techniques, i.e., detection of amastigotes in Giemsa stained slit skin smears (SSSs), and punch biopsy and histology (Ranawaka et al 2012)
The results showed the presence of DNA in the three polymerase chain reaction (PCR) negative samples
This study for the first time systematically evaluated DNA based methods to detect Leishmania DNA in skin biopsy samples taken from Sri Lankan CL lesions
Summary
In spite of the Public Health importance of CL in Sri Lanka, diagnosis continues to be mostly based on clinical features and traditional diagnostic techniques, i.e., detection of amastigotes in Giemsa stained slit skin smears (SSSs), and punch biopsy and histology (Ranawaka et al 2012). Three different Leishmania DNA PCR assays were compared regarding sensitivity and specificity for identifying Leishmania to the species level in 38 skin biopsy samples from patients from an endemic CL focus in the north-central province of Sri Lanka where cutaneous TB and leprosy are endemic (Ranawaka et al 2010, Rathnayake et al 2010, Wijesinghe & Wijesinghe 2013, MS Sri Lanka 2014).
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