PCR-based detection of Leishmania DNA in skin samples of post kala-azar dermal leishmaniasis patients from an endemic area of Bangladesh.

Post kala-azar dermal leishmaniasis (PKDL) is a sequel of visceral leishmaniasis (VL) and PKDL patients are an important reservoir for anthroponotic transmission of VL. Therefore, diagnosis and treatment of PKDL is important for the kala-azar elimination program in South Asia, including Bangladesh. While definitive diagnosis of PKDL is still based on microscopy, despite the low sensitivity of this method of diagnosis, PCR for identification of kinetoplast DNA (kDNA) from Leishmania parasites is expected to be a rapid and sensitive diagnostic method. We attempted PCR-based diagnosis from skin biopsy specimens and compared PCR to other available detection methods in order to determine the acceptability and feasibility of the PCR diagnostic method in an endemic area of VL in Bangladesh. Both skin biopsy specimens and blood samples were collected from 110 patients suspected to have PKDL from 6 subdistrict health complexes in Mymensingh, Bangladesh. Using microscopy, we identified 32 samples (29.1%) that were positive for Leishmania. Immunochromatography tests indicated that 85 samples (77.3%) were positive for Leishmania. In contrast, a total of 104 (94.5%) samples tested positive using nested PCR, while unaffected portions of skin from PKDL patients tested negative. Sequencing analysis of the PCR products indicated that the amplified portion had more than 98% nucleotide sequence identity to the Leishmania donovani reference strain, D10. These findings indicate that the PCR method using a skin biopsy is highly sensitive and useful for confirmatory diagnosis of PKDL.