Polymerase chain reaction detection of Leishmania DNA in skin biopsy samples in Sri Lanka where the causative agent of cutaneous leishmaniasis is Leishmania donovani.

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 detect Leishmania DNA in 38 punch biopsy samples from patients presented with suspected lesions in 2010. Both, Leishmania genus-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.

Polymerase chain reaction detection of LeishmaniaDNA in skin biopsy samples in Sri Lanka where the causative agent of cutaneous leishmaniasis is Leishmania donovani

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.

Cross-sectional study to assess risk factors for leishmaniasis in an endemic region in Sri Lanka.

Sri Lanka reports significantly more cutaneous leishmaniasis (CL) cases than visceral leishmaniasis (VL) cases, both of which are caused by Leishmania donovani MON-37. A cross-sectional study conducted in an area with a high prevalence of CL prevalent included 954 participants of an estimated population of 61,674 to estimate the number of CL cases, ascertain whether there is a pool of asymptomatic VL cases, and identify risk factors for transmission. A total of 31 cases of CL were identified, of whom 21 were previously diagnosed and 10 were new cases. Using rK39 rapid diagnostic test to detect antibodies against Leishmania spp., we found that only one person was seropositive but did not have clinical symptoms of CL or VL, which indicated low transmission of VL in this area. χ(2) test, independent sample t-test, and multivariate analysis of sociodemographic and spatial distribution of environmental risk factors showed that living near paddy fields is associated with increased risk for transmission of CL (P ≤ 0.01).

Leishmania donovani zymodeme MON-37 isolated from an autochthonous visceral leishmaniasis patient in Sri Lanka.

Although the strain causing cutaneous leishmaniasis (CL) in Sri Lanka was first identified in 2003, the strain causing visceral leishmaniasis (VL) has not yet been identified. We report the first isoenzyme typing of a strain causing VL in Sri Lanka at an early stage of emergence of VL in the country. The parasite was isolated from a 57-year-old civil soldier who had been in the jungle in the Vavuniya district in the Northern Province of Sri Lanka for a period of nearly 6 months immediately before the onset of symptoms. Multilocus enzyme electrophoresis (MLEE) revealed that the strain is Leishmania donovani zymodeme MON-37, the zymodeme which was previously identified from the CL patients in the country. The MLEE analysis was confirmed by sequencing the gene encoding the 6-phosphogluconate dehydrogenase isoenzyme. This is an instance of the same Leishmania zymodeme associated with both dermotropism and viscerotropism in the same geographic region. Further investigations into the genetic structure and identification of virulence factors in the parasite and immune factors in the host are required to understand the factors responsible for different tropism shown by the same zymodeme MON-37 L. donovani from Sri Lanka.